Merge branch 'master' into Discussion-#26-Rotation-Support

.github/workflows/ci.yml

@@ -12,12 +12,6 @@ jobs:
       - uses: actions/checkout@v6
         with:
           submodules: recursive
-      - uses: actions/cache@v5
-        with:
-          path: |
-            ~/.cache/pip
-            ~/.platformio/.cache
-          key: ${{ runner.os }}-pio
       - uses: actions/setup-python@v6
         with:
           python-version: '3.14'
@@ -34,7 +28,7 @@ jobs:
           sudo apt-get install -y clang-format-21
 
       - name: Run cppcheck
-        run: pio check --fail-on-defect medium --fail-on-defect high
+        run: pio check --fail-on-defect low --fail-on-defect medium --fail-on-defect high
 
       - name: Run clang-format
         run: PATH="/usr/lib/llvm-21/bin:$PATH" ./bin/clang-format-fix && git diff --exit-code || (echo "Please run 'bin/clang-format-fix' to fix formatting issues" && exit 1)

USER_GUIDE.md

@@ -59,11 +59,32 @@ See the [webserver docs](./docs/webserver.md) for more information on how to con
 ### 3.5 Settings
 
 The Settings screen allows you to configure the device's behavior. There are a few settings you can adjust:
-- **White Sleep Screen**: Whether to use the white screen or black (inverted) default sleep screen
+- **Sleep Screen**: Which sleep screen to display when the device sleeps, options are:
+  - "Dark" (default) - The default dark sleep screen
+  - "Light" - The same default sleep screen, on a white background
+  - "Custom" - Custom images from the SD card, see [3.6 Sleep Screen](#36-sleep-screen) below for more information
+  - "Cover" - The book cover image (Note: this is experimental and may not work as expected)
 - **Extra Paragraph Spacing**: If enabled, vertical space will be added between paragraphs in the book, if disabled,
   paragraphs will not have vertical space between them, but will have first word indentation.
 - **Short Power Button Click**: Whether to trigger the power button on a short press or a long press.
 
+### 3.6 Sleep Screen
+
+You can customize the sleep screen by placing custom images in specific locations on the SD card:
+
+- **Single Image:** Place a file named `sleep.bmp` in the root directory.
+- **Multiple Images:** Create a `sleep` directory in the root of the SD card and place any number of `.bmp` images
+  inside. If images are found in this directory, they will take priority over the `sleep.png` file, and one will be
+  randomly selected each time the device sleeps.
+
+> [!NOTE]
+> You'll need to set the **Sleep Screen** setting to **Custom** in order to use these images.
+
+> [!TIP]
+> For best results:
+> - Use uncompressed BMP files with 24-bit color depth
+> - Use a resolution of 480x800 pixels to match the device's screen resolution.
+
 ---
 
 ## 4. Reading Mode

lib/EpdFont/EpdFont.cpp

@@ -59,14 +59,28 @@ bool EpdFont::hasPrintableChars(const char* string) const {
 
 const EpdGlyph* EpdFont::getGlyph(const uint32_t cp) const {
   const EpdUnicodeInterval* intervals = data->intervals;
-  for (int i = 0; i < data->intervalCount; i++) {
+  const int count = data->intervalCount;
-    const EpdUnicodeInterval* interval = &intervals[i];
+
-    if (cp >= interval->first && cp <= interval->last) {
+  if (count == 0) return nullptr;
+
+  // Binary search for O(log n) lookup instead of O(n)
+  // Critical for Korean fonts with many unicode intervals
+  int left = 0;
+  int right = count - 1;
+
+  while (left <= right) {
+    const int mid = left + (right - left) / 2;
+    const EpdUnicodeInterval* interval = &intervals[mid];
+
+    if (cp < interval->first) {
+      right = mid - 1;
+    } else if (cp > interval->last) {
+      left = mid + 1;
+    } else {
+      // Found: cp >= interval->first && cp <= interval->last
       return &data->glyph[interval->offset + (cp - interval->first)];
     }
-    if (cp < interval->first) {
-      return nullptr;
-    }
   }
+
   return nullptr;
 }

lib/Epub/Epub.cpp

@@ -1,12 +1,11 @@
 #include "Epub.h"
 
+#include <FsHelpers.h>
 #include <HardwareSerial.h>
+#include <JpegToBmpConverter.h>
 #include <SD.h>
 #include <ZipFile.h>
 
-#include <map>
-
-#include "Epub/FsHelpers.h"
 #include "Epub/parsers/ContainerParser.h"
 #include "Epub/parsers/ContentOpfParser.h"
 #include "Epub/parsers/TocNcxParser.h"
@@ -30,31 +29,39 @@ bool Epub::findContentOpfFile(std::string* contentOpfFile) const {
   // Stream read (reusing your existing stream logic)
   if (!readItemContentsToStream(containerPath, containerParser, 512)) {
     Serial.printf("[%lu] [EBP] Could not read META-INF/container.xml\n", millis());
-    containerParser.teardown();
     return false;
   }
 
   // Extract the result
   if (containerParser.fullPath.empty()) {
     Serial.printf("[%lu] [EBP] Could not find valid rootfile in container.xml\n", millis());
-    containerParser.teardown();
     return false;
   }
 
   *contentOpfFile = std::move(containerParser.fullPath);
-
-  containerParser.teardown();
   return true;
 }
 
-bool Epub::parseContentOpf(const std::string& contentOpfFilePath) {
+bool Epub::parseContentOpf(BookMetadataCache::BookMetadata& bookMetadata) {
+  std::string contentOpfFilePath;
+  if (!findContentOpfFile(&contentOpfFilePath)) {
+    Serial.printf("[%lu] [EBP] Could not find content.opf in zip\n", millis());
+    return false;
+  }
+
+  contentBasePath = contentOpfFilePath.substr(0, contentOpfFilePath.find_last_of('/') + 1);
+
+  Serial.printf("[%lu] [EBP] Parsing content.opf: %s\n", millis(), contentOpfFilePath.c_str());
+
   size_t contentOpfSize;
   if (!getItemSize(contentOpfFilePath, &contentOpfSize)) {
     Serial.printf("[%lu] [EBP] Could not get size of content.opf\n", millis());
     return false;
   }
 
-  ContentOpfParser opfParser(getBasePath(), contentOpfSize);
+  ContentOpfParser opfParser(getCachePath(), getBasePath(), contentOpfSize, bookMetadataCache.get());
+  Serial.printf("[%lu] [MEM] Free: %d bytes, Total: %d bytes, Min Free: %d bytes\n", millis(), ESP.getFreeHeap(),
+                ESP.getHeapSize(), ESP.getMinFreeHeap());
 
   if (!opfParser.setup()) {
     Serial.printf("[%lu] [EBP] Could not setup content.opf parser\n", millis());
@@ -63,139 +70,156 @@ bool Epub::parseContentOpf(const std::string& contentOpfFilePath) {
 
   if (!readItemContentsToStream(contentOpfFilePath, opfParser, 1024)) {
     Serial.printf("[%lu] [EBP] Could not read content.opf\n", millis());
-    opfParser.teardown();
     return false;
   }
 
   // Grab data from opfParser into epub
-  title = opfParser.title;
+  bookMetadata.title = opfParser.title;
-  if (!opfParser.coverItemId.empty() && opfParser.items.count(opfParser.coverItemId) > 0) {
+  // TODO: Parse author
-    coverImageItem = opfParser.items.at(opfParser.coverItemId);
+  bookMetadata.author = "";
-  }
+  bookMetadata.coverItemHref = opfParser.coverItemHref;
 
   if (!opfParser.tocNcxPath.empty()) {
     tocNcxItem = opfParser.tocNcxPath;
   }
 
-  for (auto& spineRef : opfParser.spineRefs) {
-    if (opfParser.items.count(spineRef)) {
-      spine.emplace_back(spineRef, opfParser.items.at(spineRef));
-    }
-  }
-
   Serial.printf("[%lu] [EBP] Successfully parsed content.opf\n", millis());
-
-  opfParser.teardown();
   return true;
 }
 
-bool Epub::parseTocNcxFile() {
+bool Epub::parseTocNcxFile() const {
   // the ncx file should have been specified in the content.opf file
   if (tocNcxItem.empty()) {
     Serial.printf("[%lu] [EBP] No ncx file specified\n", millis());
     return false;
   }
 
-  size_t tocSize;
+  Serial.printf("[%lu] [EBP] Parsing toc ncx file: %s\n", millis(), tocNcxItem.c_str());
-  if (!getItemSize(tocNcxItem, &tocSize)) {
+
-    Serial.printf("[%lu] [EBP] Could not get size of toc ncx\n", millis());
+  const auto tmpNcxPath = getCachePath() + "/toc.ncx";
+  File tempNcxFile;
+  if (!FsHelpers::openFileForWrite("EBP", tmpNcxPath, tempNcxFile)) {
     return false;
   }
+  readItemContentsToStream(tocNcxItem, tempNcxFile, 1024);
+  tempNcxFile.close();
+  if (!FsHelpers::openFileForRead("EBP", tmpNcxPath, tempNcxFile)) {
+    return false;
+  }
+  const auto ncxSize = tempNcxFile.size();
 
-  TocNcxParser ncxParser(contentBasePath, tocSize);
+  TocNcxParser ncxParser(contentBasePath, ncxSize, bookMetadataCache.get());
 
   if (!ncxParser.setup()) {
     Serial.printf("[%lu] [EBP] Could not setup toc ncx parser\n", millis());
     return false;
   }
 
-  if (!readItemContentsToStream(tocNcxItem, ncxParser, 1024)) {
+  const auto ncxBuffer = static_cast<uint8_t*>(malloc(1024));
-    Serial.printf("[%lu] [EBP] Could not read toc ncx stream\n", millis());
+  if (!ncxBuffer) {
-    ncxParser.teardown();
+    Serial.printf("[%lu] [EBP] Could not allocate memory for toc ncx parser\n", millis());
     return false;
   }
 
-  this->toc = std::move(ncxParser.toc);
+  while (tempNcxFile.available()) {
+    const auto readSize = tempNcxFile.read(ncxBuffer, 1024);
+    const auto processedSize = ncxParser.write(ncxBuffer, readSize);
 
-  Serial.printf("[%lu] [EBP] Parsed %d TOC items\n", millis(), this->toc.size());
+    if (processedSize != readSize) {
+      Serial.printf("[%lu] [EBP] Could not process all toc ncx data\n", millis());
+      free(ncxBuffer);
+      tempNcxFile.close();
+      return false;
+    }
+  }
 
-  ncxParser.teardown();
+  free(ncxBuffer);
+  tempNcxFile.close();
+  SD.remove(tmpNcxPath.c_str());
+
+  Serial.printf("[%lu] [EBP] Parsed TOC items\n", millis());
   return true;
 }
 
 // load in the meta data for the epub file
 bool Epub::load() {
   Serial.printf("[%lu] [EBP] Loading ePub: %s\n", millis(), filepath.c_str());
-  ZipFile zip("/sd" + filepath);
 
-  std::string contentOpfFilePath;
+  // Initialize spine/TOC cache
-  if (!findContentOpfFile(&contentOpfFilePath)) {
+  bookMetadataCache.reset(new BookMetadataCache(cachePath));
-    Serial.printf("[%lu] [EBP] Could not find content.opf in zip\n", millis());
+
+  // Try to load existing cache first
+  if (bookMetadataCache->load()) {
+    Serial.printf("[%lu] [EBP] Loaded ePub: %s\n", millis(), filepath.c_str());
+    return true;
+  }
+
+  // Cache doesn't exist or is invalid, build it
+  Serial.printf("[%lu] [EBP] Cache not found, building spine/TOC cache\n", millis());
+  setupCacheDir();
+
+  // Begin building cache - stream entries to disk immediately
+  if (!bookMetadataCache->beginWrite()) {
+    Serial.printf("[%lu] [EBP] Could not begin writing cache\n", millis());
     return false;
   }
 
-  Serial.printf("[%lu] [EBP] Found content.opf at: %s\n", millis(), contentOpfFilePath.c_str());
+  // OPF Pass
-
+  BookMetadataCache::BookMetadata bookMetadata;
-  contentBasePath = contentOpfFilePath.substr(0, contentOpfFilePath.find_last_of('/') + 1);
+  if (!bookMetadataCache->beginContentOpfPass()) {
-
+    Serial.printf("[%lu] [EBP] Could not begin writing content.opf pass\n", millis());
-  if (!parseContentOpf(contentOpfFilePath)) {
+    return false;
+  }
+  if (!parseContentOpf(bookMetadata)) {
     Serial.printf("[%lu] [EBP] Could not parse content.opf\n", millis());
     return false;
   }
+  if (!bookMetadataCache->endContentOpfPass()) {
+    Serial.printf("[%lu] [EBP] Could not end writing content.opf pass\n", millis());
+    return false;
+  }
 
+  // TOC Pass
+  if (!bookMetadataCache->beginTocPass()) {
+    Serial.printf("[%lu] [EBP] Could not begin writing toc pass\n", millis());
+    return false;
+  }
   if (!parseTocNcxFile()) {
     Serial.printf("[%lu] [EBP] Could not parse toc\n", millis());
     return false;
   }
+  if (!bookMetadataCache->endTocPass()) {
+    Serial.printf("[%lu] [EBP] Could not end writing toc pass\n", millis());
+    return false;
+  }
+
+  // Close the cache files
+  if (!bookMetadataCache->endWrite()) {
+    Serial.printf("[%lu] [EBP] Could not end writing cache\n", millis());
+    return false;
+  }
+
+  // Build final book.bin
+  if (!bookMetadataCache->buildBookBin(filepath, bookMetadata)) {
+    Serial.printf("[%lu] [EBP] Could not update mappings and sizes\n", millis());
+    return false;
+  }
+
+  if (!bookMetadataCache->cleanupTmpFiles()) {
+    Serial.printf("[%lu] [EBP] Could not cleanup tmp files - ignoring\n", millis());
+  }
+
+  // Reload the cache from disk so it's in the correct state
+  bookMetadataCache.reset(new BookMetadataCache(cachePath));
+  if (!bookMetadataCache->load()) {
+    Serial.printf("[%lu] [EBP] Failed to reload cache after writing\n", millis());
+    return false;
+  }
 
-  initializeSpineItemSizes();
   Serial.printf("[%lu] [EBP] Loaded ePub: %s\n", millis(), filepath.c_str());
-
   return true;
 }
 
-void Epub::initializeSpineItemSizes() {
-  setupCacheDir();
-
-  size_t spineItemsCount = getSpineItemsCount();
-  size_t cumSpineItemSize = 0;
-  if (SD.exists((getCachePath() + "/spine_size.bin").c_str())) {
-    File f = SD.open((getCachePath() + "/spine_size.bin").c_str());
-    uint8_t data[4];
-    for (size_t i = 0; i < spineItemsCount; i++) {
-      f.read(data, 4);
-      cumSpineItemSize = data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
-      cumulativeSpineItemSize.emplace_back(cumSpineItemSize);
-      // Serial.printf("[%lu] [EBP] Loading item %d size %u to %u %u\n", millis(),
-      //     i, cumSpineItemSize, data[1], data[0]);
-    }
-    f.close();
-  } else {
-    File f = SD.open((getCachePath() + "/spine_size.bin").c_str(), FILE_WRITE);
-    uint8_t data[4];
-    // determine size of spine items
-    for (size_t i = 0; i < spineItemsCount; i++) {
-      std::string spineItem = getSpineItem(i);
-      size_t s = 0;
-      getItemSize(spineItem, &s);
-      cumSpineItemSize += s;
-      cumulativeSpineItemSize.emplace_back(cumSpineItemSize);
-
-      // and persist to cache
-      data[0] = cumSpineItemSize & 0xFF;
-      data[1] = (cumSpineItemSize >> 8) & 0xFF;
-      data[2] = (cumSpineItemSize >> 16) & 0xFF;
-      data[3] = (cumSpineItemSize >> 24) & 0xFF;
-      // Serial.printf("[%lu] [EBP] Persisting item %d size %u to %u %u\n", millis(),
-      //     i, cumSpineItemSize, data[1], data[0]);
-      f.write(data, 4);
-    }
-
-    f.close();
-  }
-  Serial.printf("[%lu] [EBP] Book size: %lu\n", millis(), cumSpineItemSize);
-}
-
 bool Epub::clearCache() const {
   if (!SD.exists(cachePath.c_str())) {
     Serial.printf("[%lu] [EPB] Cache does not exist, no action needed\n", millis());
@@ -229,49 +253,76 @@ const std::string& Epub::getCachePath() const { return cachePath; }
 
 const std::string& Epub::getPath() const { return filepath; }
 
-const std::string& Epub::getTitle() const { return title; }
+const std::string& Epub::getTitle() const {
-
+  static std::string blank;
-const std::string& Epub::getCoverImageItem() const { return coverImageItem; }
+  if (!bookMetadataCache || !bookMetadataCache->isLoaded()) {
-
+    return blank;
-std::string normalisePath(const std::string& path) {
-  std::vector<std::string> components;
-  std::string component;
-
-  for (const auto c : path) {
-    if (c == '/') {
-      if (!component.empty()) {
-        if (component == "..") {
-          if (!components.empty()) {
-            components.pop_back();
-          }
-        } else {
-          components.push_back(component);
-        }
-        component.clear();
-      }
-    } else {
-      component += c;
-    }
   }
 
-  if (!component.empty()) {
+  return bookMetadataCache->coreMetadata.title;
-    components.push_back(component);
-  }
-
-  std::string result;
-  for (const auto& c : components) {
-    if (!result.empty()) {
-      result += "/";
-    }
-    result += c;
-  }
-
-  return result;
 }
 
-uint8_t* Epub::readItemContentsToBytes(const std::string& itemHref, size_t* size, bool trailingNullByte) const {
+std::string Epub::getCoverBmpPath() const { return cachePath + "/cover.bmp"; }
+
+bool Epub::generateCoverBmp() const {
+  // Already generated, return true
+  if (SD.exists(getCoverBmpPath().c_str())) {
+    return true;
+  }
+
+  if (!bookMetadataCache || !bookMetadataCache->isLoaded()) {
+    Serial.printf("[%lu] [EBP] Cannot generate cover BMP, cache not loaded\n", millis());
+    return false;
+  }
+
+  const auto coverImageHref = bookMetadataCache->coreMetadata.coverItemHref;
+  if (coverImageHref.empty()) {
+    Serial.printf("[%lu] [EBP] No known cover image\n", millis());
+    return false;
+  }
+
+  if (coverImageHref.substr(coverImageHref.length() - 4) == ".jpg" ||
+      coverImageHref.substr(coverImageHref.length() - 5) == ".jpeg") {
+    Serial.printf("[%lu] [EBP] Generating BMP from JPG cover image\n", millis());
+    const auto coverJpgTempPath = getCachePath() + "/.cover.jpg";
+
+    File coverJpg;
+    if (!FsHelpers::openFileForWrite("EBP", coverJpgTempPath, coverJpg)) {
+      return false;
+    }
+    readItemContentsToStream(coverImageHref, coverJpg, 1024);
+    coverJpg.close();
+
+    if (!FsHelpers::openFileForRead("EBP", coverJpgTempPath, coverJpg)) {
+      return false;
+    }
+
+    File coverBmp;
+    if (!FsHelpers::openFileForWrite("EBP", getCoverBmpPath(), coverBmp)) {
+      coverJpg.close();
+      return false;
+    }
+    const bool success = JpegToBmpConverter::jpegFileToBmpStream(coverJpg, coverBmp);
+    coverJpg.close();
+    coverBmp.close();
+    SD.remove(coverJpgTempPath.c_str());
+
+    if (!success) {
+      Serial.printf("[%lu] [EBP] Failed to generate BMP from JPG cover image\n", millis());
+      SD.remove(getCoverBmpPath().c_str());
+    }
+    Serial.printf("[%lu] [EBP] Generated BMP from JPG cover image, success: %s\n", millis(), success ? "yes" : "no");
+    return success;
+  } else {
+    Serial.printf("[%lu] [EBP] Cover image is not a JPG, skipping\n", millis());
+  }
+
+  return false;
+}
+
+uint8_t* Epub::readItemContentsToBytes(const std::string& itemHref, size_t* size, const bool trailingNullByte) const {
   const ZipFile zip("/sd" + filepath);
-  const std::string path = normalisePath(itemHref);
+  const std::string path = FsHelpers::normalisePath(itemHref);
 
   const auto content = zip.readFileToMemory(path.c_str(), size, trailingNullByte);
   if (!content) {
@@ -284,95 +335,104 @@ uint8_t* Epub::readItemContentsToBytes(const std::string& itemHref, size_t* size
 
 bool Epub::readItemContentsToStream(const std::string& itemHref, Print& out, const size_t chunkSize) const {
   const ZipFile zip("/sd" + filepath);
-  const std::string path = normalisePath(itemHref);
+  const std::string path = FsHelpers::normalisePath(itemHref);
 
   return zip.readFileToStream(path.c_str(), out, chunkSize);
 }
 
 bool Epub::getItemSize(const std::string& itemHref, size_t* size) const {
   const ZipFile zip("/sd" + filepath);
-  const std::string path = normalisePath(itemHref);
+  return getItemSize(zip, itemHref, size);
+}
 
+bool Epub::getItemSize(const ZipFile& zip, const std::string& itemHref, size_t* size) {
+  const std::string path = FsHelpers::normalisePath(itemHref);
   return zip.getInflatedFileSize(path.c_str(), size);
 }
 
-int Epub::getSpineItemsCount() const { return spine.size(); }
+int Epub::getSpineItemsCount() const {
+  if (!bookMetadataCache || !bookMetadataCache->isLoaded()) {
+    return 0;
+  }
+  return bookMetadataCache->getSpineCount();
+}
 
-size_t Epub::getCumulativeSpineItemSize(const int spineIndex) const { return cumulativeSpineItemSize.at(spineIndex); }
+size_t Epub::getCumulativeSpineItemSize(const int spineIndex) const { return getSpineItem(spineIndex).cumulativeSize; }
 
-std::string& Epub::getSpineItem(const int spineIndex) {
+BookMetadataCache::SpineEntry Epub::getSpineItem(const int spineIndex) const {
-  if (spineIndex < 0 || spineIndex >= spine.size()) {
+  if (!bookMetadataCache || !bookMetadataCache->isLoaded()) {
+    Serial.printf("[%lu] [EBP] getSpineItem called but cache not loaded\n", millis());
+    return {};
+  }
+
+  if (spineIndex < 0 || spineIndex >= bookMetadataCache->getSpineCount()) {
     Serial.printf("[%lu] [EBP] getSpineItem index:%d is out of range\n", millis(), spineIndex);
-    return spine.at(0).second;
+    return bookMetadataCache->getSpineEntry(0);
   }
 
-  return spine.at(spineIndex).second;
+  return bookMetadataCache->getSpineEntry(spineIndex);
 }
 
-EpubTocEntry& Epub::getTocItem(const int tocTndex) {
+BookMetadataCache::TocEntry Epub::getTocItem(const int tocIndex) const {
-  if (tocTndex < 0 || tocTndex >= toc.size()) {
+  if (!bookMetadataCache || !bookMetadataCache->isLoaded()) {
-    Serial.printf("[%lu] [EBP] getTocItem index:%d is out of range\n", millis(), tocTndex);
+    Serial.printf("[%lu] [EBP] getTocItem called but cache not loaded\n", millis());
-    return toc.at(0);
+    return {};
   }
 
-  return toc.at(tocTndex);
+  if (tocIndex < 0 || tocIndex >= bookMetadataCache->getTocCount()) {
+    Serial.printf("[%lu] [EBP] getTocItem index:%d is out of range\n", millis(), tocIndex);
+    return {};
+  }
+
+  return bookMetadataCache->getTocEntry(tocIndex);
 }
 
-int Epub::getTocItemsCount() const { return toc.size(); }
+int Epub::getTocItemsCount() const {
+  if (!bookMetadataCache || !bookMetadataCache->isLoaded()) {
+    return 0;
+  }
+
+  return bookMetadataCache->getTocCount();
+}
 
 // work out the section index for a toc index
 int Epub::getSpineIndexForTocIndex(const int tocIndex) const {
-  if (tocIndex < 0 || tocIndex >= toc.size()) {
+  if (!bookMetadataCache || !bookMetadataCache->isLoaded()) {
+    Serial.printf("[%lu] [EBP] getSpineIndexForTocIndex called but cache not loaded\n", millis());
+    return 0;
+  }
+
+  if (tocIndex < 0 || tocIndex >= bookMetadataCache->getTocCount()) {
     Serial.printf("[%lu] [EBP] getSpineIndexForTocIndex: tocIndex %d out of range\n", millis(), tocIndex);
     return 0;
   }
 
-  // the toc entry should have an href that matches the spine item
+  const int spineIndex = bookMetadataCache->getTocEntry(tocIndex).spineIndex;
-  // so we can find the spine index by looking for the href
+  if (spineIndex < 0) {
-  for (int i = 0; i < spine.size(); i++) {
+    Serial.printf("[%lu] [EBP] Section not found for TOC index %d\n", millis(), tocIndex);
-    if (spine[i].second == toc[tocIndex].href) {
-      return i;
-    }
-  }
-
-  Serial.printf("[%lu] [EBP] Section not found\n", millis());
-  // not found - default to the start of the book
     return 0;
+  }
+
+  return spineIndex;
 }
 
-int Epub::getTocIndexForSpineIndex(const int spineIndex) const {
+int Epub::getTocIndexForSpineIndex(const int spineIndex) const { return getSpineItem(spineIndex).tocIndex; }
-  if (spineIndex < 0 || spineIndex >= spine.size()) {
-    Serial.printf("[%lu] [EBP] getTocIndexForSpineIndex: spineIndex %d out of range\n", millis(), spineIndex);
-    return -1;
-  }
-
-  // the toc entry should have an href that matches the spine item
-  // so we can find the toc index by looking for the href
-  for (int i = 0; i < toc.size(); i++) {
-    if (toc[i].href == spine[spineIndex].second) {
-      return i;
-    }
-  }
-
-  Serial.printf("[%lu] [EBP] TOC item not found\n", millis());
-  return -1;
-}
 
 size_t Epub::getBookSize() const {
-  if (spine.empty()) {
+  if (!bookMetadataCache || !bookMetadataCache->isLoaded() || bookMetadataCache->getSpineCount() == 0) {
     return 0;
   }
   return getCumulativeSpineItemSize(getSpineItemsCount() - 1);
 }
 
 // Calculate progress in book
-uint8_t Epub::calculateProgress(const int currentSpineIndex, const float currentSpineRead) {
+uint8_t Epub::calculateProgress(const int currentSpineIndex, const float currentSpineRead) const {
-  size_t bookSize = getBookSize();
+  const size_t bookSize = getBookSize();
   if (bookSize == 0) {
     return 0;
   }
-  size_t prevChapterSize = (currentSpineIndex >= 1) ? getCumulativeSpineItemSize(currentSpineIndex - 1) : 0;
+  const size_t prevChapterSize = (currentSpineIndex >= 1) ? getCumulativeSpineItemSize(currentSpineIndex - 1) : 0;
-  size_t curChapterSize = getCumulativeSpineItemSize(currentSpineIndex) - prevChapterSize;
+  const size_t curChapterSize = getCumulativeSpineItemSize(currentSpineIndex) - prevChapterSize;
-  size_t sectionProgSize = currentSpineRead * curChapterSize;
+  const size_t sectionProgSize = currentSpineRead * curChapterSize;
   return round(static_cast<float>(prevChapterSize + sectionProgSize) / bookSize * 100.0);
 }

lib/Epub/Epub.h

@@ -1,38 +1,30 @@
 #pragma once
-#include <Print.h>
 
+#include <memory>
 #include <string>
 #include <unordered_map>
 #include <vector>
 
-#include "Epub/EpubTocEntry.h"
+#include "Epub/BookMetadataCache.h"
 
 class ZipFile;
 
 class Epub {
-  // the title read from the EPUB meta data
-  std::string title;
-  // the cover image
-  std::string coverImageItem;
   // the ncx file
   std::string tocNcxItem;
   // where is the EPUBfile?
   std::string filepath;
-  // the spine of the EPUB file
-  std::vector<std::pair<std::string, std::string>> spine;
-  // the file size of the spine items (proxy to book progress)
-  std::vector<size_t> cumulativeSpineItemSize;
-  // the toc of the EPUB file
-  std::vector<EpubTocEntry> toc;
   // the base path for items in the EPUB file
   std::string contentBasePath;
   // Uniq cache key based on filepath
   std::string cachePath;
+  // Spine and TOC cache
+  std::unique_ptr<BookMetadataCache> bookMetadataCache;
 
   bool findContentOpfFile(std::string* contentOpfFile) const;
-  bool parseContentOpf(const std::string& contentOpfFilePath);
+  bool parseContentOpf(BookMetadataCache::BookMetadata& bookMetadata);
-  bool parseTocNcxFile();
+  bool parseTocNcxFile() const;
-  void initializeSpineItemSizes();
+  static bool getItemSize(const ZipFile& zip, const std::string& itemHref, size_t* size);
 
  public:
   explicit Epub(std::string filepath, const std::string& cacheDir) : filepath(std::move(filepath)) {
@@ -47,19 +39,20 @@ class Epub {
   const std::string& getCachePath() const;
   const std::string& getPath() const;
   const std::string& getTitle() const;
-  const std::string& getCoverImageItem() const;
+  std::string getCoverBmpPath() const;
+  bool generateCoverBmp() const;
   uint8_t* readItemContentsToBytes(const std::string& itemHref, size_t* size = nullptr,
                                    bool trailingNullByte = false) const;
   bool readItemContentsToStream(const std::string& itemHref, Print& out, size_t chunkSize) const;
   bool getItemSize(const std::string& itemHref, size_t* size) const;
-  std::string& getSpineItem(int spineIndex);
+  BookMetadataCache::SpineEntry getSpineItem(int spineIndex) const;
+  BookMetadataCache::TocEntry getTocItem(int tocIndex) const;
   int getSpineItemsCount() const;
-  size_t getCumulativeSpineItemSize(const int spineIndex) const;
-  EpubTocEntry& getTocItem(int tocIndex);
   int getTocItemsCount() const;
   int getSpineIndexForTocIndex(int tocIndex) const;
   int getTocIndexForSpineIndex(int spineIndex) const;
+  size_t getCumulativeSpineItemSize(int spineIndex) const;
 
   size_t getBookSize() const;
-  uint8_t calculateProgress(const int currentSpineIndex, const float currentSpineRead);
+  uint8_t calculateProgress(const int currentSpineIndex, const float currentSpineRead) const;
 };

lib/Epub/Epub/BookMetadataCache.cpp

@@ -0,0 +1,326 @@
+#include "BookMetadataCache.h"
+
+#include <HardwareSerial.h>
+#include <SD.h>
+#include <Serialization.h>
+#include <ZipFile.h>
+
+#include <vector>
+
+#include "FsHelpers.h"
+
+namespace {
+constexpr uint8_t BOOK_CACHE_VERSION = 1;
+constexpr char bookBinFile[] = "/book.bin";
+constexpr char tmpSpineBinFile[] = "/spine.bin.tmp";
+constexpr char tmpTocBinFile[] = "/toc.bin.tmp";
+}  // namespace
+
+/* ============= WRITING / BUILDING FUNCTIONS ================ */
+
+bool BookMetadataCache::beginWrite() {
+  buildMode = true;
+  spineCount = 0;
+  tocCount = 0;
+  Serial.printf("[%lu] [BMC] Entering write mode\n", millis());
+  return true;
+}
+
+bool BookMetadataCache::beginContentOpfPass() {
+  Serial.printf("[%lu] [BMC] Beginning content opf pass\n", millis());
+
+  // Open spine file for writing
+  return FsHelpers::openFileForWrite("BMC", cachePath + tmpSpineBinFile, spineFile);
+}
+
+bool BookMetadataCache::endContentOpfPass() {
+  spineFile.close();
+  return true;
+}
+
+bool BookMetadataCache::beginTocPass() {
+  Serial.printf("[%lu] [BMC] Beginning toc pass\n", millis());
+
+  // Open spine file for reading
+  if (!FsHelpers::openFileForRead("BMC", cachePath + tmpSpineBinFile, spineFile)) {
+    return false;
+  }
+  if (!FsHelpers::openFileForWrite("BMC", cachePath + tmpTocBinFile, tocFile)) {
+    spineFile.close();
+    return false;
+  }
+  return true;
+}
+
+bool BookMetadataCache::endTocPass() {
+  tocFile.close();
+  spineFile.close();
+  return true;
+}
+
+bool BookMetadataCache::endWrite() {
+  if (!buildMode) {
+    Serial.printf("[%lu] [BMC] endWrite called but not in build mode\n", millis());
+    return false;
+  }
+
+  buildMode = false;
+  Serial.printf("[%lu] [BMC] Wrote %d spine, %d TOC entries\n", millis(), spineCount, tocCount);
+  return true;
+}
+
+bool BookMetadataCache::buildBookBin(const std::string& epubPath, const BookMetadata& metadata) {
+  // Open all three files, writing to meta, reading from spine and toc
+  if (!FsHelpers::openFileForWrite("BMC", cachePath + bookBinFile, bookFile)) {
+    return false;
+  }
+
+  if (!FsHelpers::openFileForRead("BMC", cachePath + tmpSpineBinFile, spineFile)) {
+    bookFile.close();
+    return false;
+  }
+
+  if (!FsHelpers::openFileForRead("BMC", cachePath + tmpTocBinFile, tocFile)) {
+    bookFile.close();
+    spineFile.close();
+    return false;
+  }
+
+  constexpr size_t headerASize =
+      sizeof(BOOK_CACHE_VERSION) + /* LUT Offset */ sizeof(size_t) + sizeof(spineCount) + sizeof(tocCount);
+  const size_t metadataSize =
+      metadata.title.size() + metadata.author.size() + metadata.coverItemHref.size() + sizeof(uint32_t) * 3;
+  const size_t lutSize = sizeof(size_t) * spineCount + sizeof(size_t) * tocCount;
+  const size_t lutOffset = headerASize + metadataSize;
+
+  // Header A
+  serialization::writePod(bookFile, BOOK_CACHE_VERSION);
+  serialization::writePod(bookFile, lutOffset);
+  serialization::writePod(bookFile, spineCount);
+  serialization::writePod(bookFile, tocCount);
+  // Metadata
+  serialization::writeString(bookFile, metadata.title);
+  serialization::writeString(bookFile, metadata.author);
+  serialization::writeString(bookFile, metadata.coverItemHref);
+
+  // Loop through spine entries, writing LUT positions
+  spineFile.seek(0);
+  for (int i = 0; i < spineCount; i++) {
+    auto pos = spineFile.position();
+    auto spineEntry = readSpineEntry(spineFile);
+    serialization::writePod(bookFile, pos + lutOffset + lutSize);
+  }
+
+  // Loop through toc entries, writing LUT positions
+  tocFile.seek(0);
+  for (int i = 0; i < tocCount; i++) {
+    auto pos = tocFile.position();
+    auto tocEntry = readTocEntry(tocFile);
+    serialization::writePod(bookFile, pos + lutOffset + lutSize + spineFile.position());
+  }
+
+  // LUTs complete
+  // Loop through spines from spine file matching up TOC indexes, calculating cumulative size and writing to book.bin
+
+  const ZipFile zip("/sd" + epubPath);
+  size_t cumSize = 0;
+  spineFile.seek(0);
+  for (int i = 0; i < spineCount; i++) {
+    auto spineEntry = readSpineEntry(spineFile);
+
+    tocFile.seek(0);
+    for (int j = 0; j < tocCount; j++) {
+      auto tocEntry = readTocEntry(tocFile);
+      if (tocEntry.spineIndex == i) {
+        spineEntry.tocIndex = j;
+        break;
+      }
+    }
+
+    // Not a huge deal if we don't fine a TOC entry for the spine entry, this is expected behaviour for EPUBs
+    // Logging here is for debugging
+    if (spineEntry.tocIndex == -1) {
+      Serial.printf("[%lu] [BMC] Warning: Could not find TOC entry for spine item %d: %s\n", millis(), i,
+                    spineEntry.href.c_str());
+    }
+
+    // Calculate size for cumulative size
+    size_t itemSize = 0;
+    const std::string path = FsHelpers::normalisePath(spineEntry.href);
+    if (zip.getInflatedFileSize(path.c_str(), &itemSize)) {
+      cumSize += itemSize;
+      spineEntry.cumulativeSize = cumSize;
+    } else {
+      Serial.printf("[%lu] [BMC] Warning: Could not get size for spine item: %s\n", millis(), path.c_str());
+    }
+
+    // Write out spine data to book.bin
+    writeSpineEntry(bookFile, spineEntry);
+  }
+
+  // Loop through toc entries from toc file writing to book.bin
+  tocFile.seek(0);
+  for (int i = 0; i < tocCount; i++) {
+    auto tocEntry = readTocEntry(tocFile);
+    writeTocEntry(bookFile, tocEntry);
+  }
+
+  bookFile.close();
+  spineFile.close();
+  tocFile.close();
+
+  Serial.printf("[%lu] [BMC] Successfully built book.bin\n", millis());
+  return true;
+}
+
+bool BookMetadataCache::cleanupTmpFiles() const {
+  if (SD.exists((cachePath + tmpSpineBinFile).c_str())) {
+    SD.remove((cachePath + tmpSpineBinFile).c_str());
+  }
+  if (SD.exists((cachePath + tmpTocBinFile).c_str())) {
+    SD.remove((cachePath + tmpTocBinFile).c_str());
+  }
+  return true;
+}
+
+size_t BookMetadataCache::writeSpineEntry(File& file, const SpineEntry& entry) const {
+  const auto pos = file.position();
+  serialization::writeString(file, entry.href);
+  serialization::writePod(file, entry.cumulativeSize);
+  serialization::writePod(file, entry.tocIndex);
+  return pos;
+}
+
+size_t BookMetadataCache::writeTocEntry(File& file, const TocEntry& entry) const {
+  const auto pos = file.position();
+  serialization::writeString(file, entry.title);
+  serialization::writeString(file, entry.href);
+  serialization::writeString(file, entry.anchor);
+  serialization::writePod(file, entry.level);
+  serialization::writePod(file, entry.spineIndex);
+  return pos;
+}
+
+// Note: for the LUT to be accurate, this **MUST** be called for all spine items before `addTocEntry` is ever called
+// this is because in this function we're marking positions of the items
+void BookMetadataCache::createSpineEntry(const std::string& href) {
+  if (!buildMode || !spineFile) {
+    Serial.printf("[%lu] [BMC] createSpineEntry called but not in build mode\n", millis());
+    return;
+  }
+
+  const SpineEntry entry(href, 0, -1);
+  writeSpineEntry(spineFile, entry);
+  spineCount++;
+}
+
+void BookMetadataCache::createTocEntry(const std::string& title, const std::string& href, const std::string& anchor,
+                                       const uint8_t level) {
+  if (!buildMode || !tocFile || !spineFile) {
+    Serial.printf("[%lu] [BMC] createTocEntry called but not in build mode\n", millis());
+    return;
+  }
+
+  int spineIndex = -1;
+  // find spine index
+  spineFile.seek(0);
+  for (int i = 0; i < spineCount; i++) {
+    auto spineEntry = readSpineEntry(spineFile);
+    if (spineEntry.href == href) {
+      spineIndex = i;
+      break;
+    }
+  }
+
+  if (spineIndex == -1) {
+    Serial.printf("[%lu] [BMC] addTocEntry: Could not find spine item for TOC href %s\n", millis(), href.c_str());
+  }
+
+  const TocEntry entry(title, href, anchor, level, spineIndex);
+  writeTocEntry(tocFile, entry);
+  tocCount++;
+}
+
+/* ============= READING / LOADING FUNCTIONS ================ */
+
+bool BookMetadataCache::load() {
+  if (!FsHelpers::openFileForRead("BMC", cachePath + bookBinFile, bookFile)) {
+    return false;
+  }
+
+  uint8_t version;
+  serialization::readPod(bookFile, version);
+  if (version != BOOK_CACHE_VERSION) {
+    Serial.printf("[%lu] [BMC] Cache version mismatch: expected %d, got %d\n", millis(), BOOK_CACHE_VERSION, version);
+    bookFile.close();
+    return false;
+  }
+
+  serialization::readPod(bookFile, lutOffset);
+  serialization::readPod(bookFile, spineCount);
+  serialization::readPod(bookFile, tocCount);
+
+  serialization::readString(bookFile, coreMetadata.title);
+  serialization::readString(bookFile, coreMetadata.author);
+  serialization::readString(bookFile, coreMetadata.coverItemHref);
+
+  loaded = true;
+  Serial.printf("[%lu] [BMC] Loaded cache data: %d spine, %d TOC entries\n", millis(), spineCount, tocCount);
+  return true;
+}
+
+BookMetadataCache::SpineEntry BookMetadataCache::getSpineEntry(const int index) {
+  if (!loaded) {
+    Serial.printf("[%lu] [BMC] getSpineEntry called but cache not loaded\n", millis());
+    return {};
+  }
+
+  if (index < 0 || index >= static_cast<int>(spineCount)) {
+    Serial.printf("[%lu] [BMC] getSpineEntry index %d out of range\n", millis(), index);
+    return {};
+  }
+
+  // Seek to spine LUT item, read from LUT and get out data
+  bookFile.seek(lutOffset + sizeof(size_t) * index);
+  size_t spineEntryPos;
+  serialization::readPod(bookFile, spineEntryPos);
+  bookFile.seek(spineEntryPos);
+  return readSpineEntry(bookFile);
+}
+
+BookMetadataCache::TocEntry BookMetadataCache::getTocEntry(const int index) {
+  if (!loaded) {
+    Serial.printf("[%lu] [BMC] getTocEntry called but cache not loaded\n", millis());
+    return {};
+  }
+
+  if (index < 0 || index >= static_cast<int>(tocCount)) {
+    Serial.printf("[%lu] [BMC] getTocEntry index %d out of range\n", millis(), index);
+    return {};
+  }
+
+  // Seek to TOC LUT item, read from LUT and get out data
+  bookFile.seek(lutOffset + sizeof(size_t) * spineCount + sizeof(size_t) * index);
+  size_t tocEntryPos;
+  serialization::readPod(bookFile, tocEntryPos);
+  bookFile.seek(tocEntryPos);
+  return readTocEntry(bookFile);
+}
+
+BookMetadataCache::SpineEntry BookMetadataCache::readSpineEntry(File& file) const {
+  SpineEntry entry;
+  serialization::readString(file, entry.href);
+  serialization::readPod(file, entry.cumulativeSize);
+  serialization::readPod(file, entry.tocIndex);
+  return entry;
+}
+
+BookMetadataCache::TocEntry BookMetadataCache::readTocEntry(File& file) const {
+  TocEntry entry;
+  serialization::readString(file, entry.title);
+  serialization::readString(file, entry.href);
+  serialization::readString(file, entry.anchor);
+  serialization::readPod(file, entry.level);
+  serialization::readPod(file, entry.spineIndex);
+  return entry;
+}

lib/Epub/Epub/BookMetadataCache.h

@@ -0,0 +1,87 @@
+#pragma once
+
+#include <SD.h>
+
+#include <string>
+
+class BookMetadataCache {
+ public:
+  struct BookMetadata {
+    std::string title;
+    std::string author;
+    std::string coverItemHref;
+  };
+
+  struct SpineEntry {
+    std::string href;
+    size_t cumulativeSize;
+    int16_t tocIndex;
+
+    SpineEntry() : cumulativeSize(0), tocIndex(-1) {}
+    SpineEntry(std::string href, const size_t cumulativeSize, const int16_t tocIndex)
+        : href(std::move(href)), cumulativeSize(cumulativeSize), tocIndex(tocIndex) {}
+  };
+
+  struct TocEntry {
+    std::string title;
+    std::string href;
+    std::string anchor;
+    uint8_t level;
+    int16_t spineIndex;
+
+    TocEntry() : level(0), spineIndex(-1) {}
+    TocEntry(std::string title, std::string href, std::string anchor, const uint8_t level, const int16_t spineIndex)
+        : title(std::move(title)),
+          href(std::move(href)),
+          anchor(std::move(anchor)),
+          level(level),
+          spineIndex(spineIndex) {}
+  };
+
+ private:
+  std::string cachePath;
+  size_t lutOffset;
+  uint16_t spineCount;
+  uint16_t tocCount;
+  bool loaded;
+  bool buildMode;
+
+  File bookFile;
+  // Temp file handles during build
+  File spineFile;
+  File tocFile;
+
+  size_t writeSpineEntry(File& file, const SpineEntry& entry) const;
+  size_t writeTocEntry(File& file, const TocEntry& entry) const;
+  SpineEntry readSpineEntry(File& file) const;
+  TocEntry readTocEntry(File& file) const;
+
+ public:
+  BookMetadata coreMetadata;
+
+  explicit BookMetadataCache(std::string cachePath)
+      : cachePath(std::move(cachePath)), lutOffset(0), spineCount(0), tocCount(0), loaded(false), buildMode(false) {}
+  ~BookMetadataCache() = default;
+
+  // Building phase (stream to disk immediately)
+  bool beginWrite();
+  bool beginContentOpfPass();
+  void createSpineEntry(const std::string& href);
+  bool endContentOpfPass();
+  bool beginTocPass();
+  void createTocEntry(const std::string& title, const std::string& href, const std::string& anchor, uint8_t level);
+  bool endTocPass();
+  bool endWrite();
+  bool cleanupTmpFiles() const;
+
+  // Post-processing to update mappings and sizes
+  bool buildBookBin(const std::string& epubPath, const BookMetadata& metadata);
+
+  // Reading phase (read mode)
+  bool load();
+  SpineEntry getSpineEntry(int index);
+  TocEntry getTocEntry(int index);
+  int getSpineCount() const { return spineCount; }
+  int getTocCount() const { return tocCount; }
+  bool isLoaded() const { return loaded; }
+};

lib/Epub/Epub/EpubTocEntry.h

@@ -1,13 +0,0 @@
-#pragma once
-
-#include <string>
-
-class EpubTocEntry {
- public:
-  std::string title;
-  std::string href;
-  std::string anchor;
-  int level;
-  EpubTocEntry(std::string title, std::string href, std::string anchor, const int level)
-      : title(std::move(title)), href(std::move(href)), anchor(std::move(anchor)), level(level) {}
-};

lib/Epub/Epub/FsHelpers.cpp

@@ -2,6 +2,26 @@
 
 #include <SD.h>
 
+#include <vector>
+
+bool FsHelpers::openFileForRead(const char* moduleName, const std::string& path, File& file) {
+  file = SD.open(path.c_str(), FILE_READ);
+  if (!file) {
+    Serial.printf("[%lu] [%s] Failed to open file for reading: %s\n", millis(), moduleName, path.c_str());
+    return false;
+  }
+  return true;
+}
+
+bool FsHelpers::openFileForWrite(const char* moduleName, const std::string& path, File& file) {
+  file = SD.open(path.c_str(), FILE_WRITE, true);
+  if (!file) {
+    Serial.printf("[%lu] [%s] Failed to open file for writing: %s\n", millis(), moduleName, path.c_str());
+    return false;
+  }
+  return true;
+}
+
 bool FsHelpers::removeDir(const char* path) {
   // 1. Open the directory
   File dir = SD.open(path);
@@ -34,3 +54,39 @@ bool FsHelpers::removeDir(const char* path) {
 
   return SD.rmdir(path);
 }
+
+std::string FsHelpers::normalisePath(const std::string& path) {
+  std::vector<std::string> components;
+  std::string component;
+
+  for (const auto c : path) {
+    if (c == '/') {
+      if (!component.empty()) {
+        if (component == "..") {
+          if (!components.empty()) {
+            components.pop_back();
+          }
+        } else {
+          components.push_back(component);
+        }
+        component.clear();
+      }
+    } else {
+      component += c;
+    }
+  }
+
+  if (!component.empty()) {
+    components.push_back(component);
+  }
+
+  std::string result;
+  for (const auto& c : components) {
+    if (!result.empty()) {
+      result += "/";
+    }
+    result += c;
+  }
+
+  return result;
+}

lib/Epub/Epub/FsHelpers.h

@@ -1,6 +1,12 @@
 #pragma once
+#include <FS.h>
+
+#include <string>
 
 class FsHelpers {
  public:
+  static bool openFileForRead(const char* moduleName, const std::string& path, File& file);
+  static bool openFileForWrite(const char* moduleName, const std::string& path, File& file);
   static bool removeDir(const char* path);
+  static std::string normalisePath(const std::string& path);
 };

lib/Epub/Epub/Page.cpp

@@ -9,21 +9,21 @@ constexpr uint8_t PAGE_FILE_VERSION = 3;
 
 void PageLine::render(GfxRenderer& renderer, const int fontId) { block->render(renderer, fontId, xPos, yPos); }
 
-void PageLine::serialize(std::ostream& os) {
+void PageLine::serialize(File& file) {
-  serialization::writePod(os, xPos);
+  serialization::writePod(file, xPos);
-  serialization::writePod(os, yPos);
+  serialization::writePod(file, yPos);
 
   // serialize TextBlock pointed to by PageLine
-  block->serialize(os);
+  block->serialize(file);
 }
 
-std::unique_ptr<PageLine> PageLine::deserialize(std::istream& is) {
+std::unique_ptr<PageLine> PageLine::deserialize(File& file) {
   int16_t xPos;
   int16_t yPos;
-  serialization::readPod(is, xPos);
+  serialization::readPod(file, xPos);
-  serialization::readPod(is, yPos);
+  serialization::readPod(file, yPos);
 
-  auto tb = TextBlock::deserialize(is);
+  auto tb = TextBlock::deserialize(file);
   return std::unique_ptr<PageLine>(new PageLine(std::move(tb), xPos, yPos));
 }
 
@@ -33,22 +33,22 @@ void Page::render(GfxRenderer& renderer, const int fontId) const {
   }
 }
 
-void Page::serialize(std::ostream& os) const {
+void Page::serialize(File& file) const {
-  serialization::writePod(os, PAGE_FILE_VERSION);
+  serialization::writePod(file, PAGE_FILE_VERSION);
 
   const uint32_t count = elements.size();
-  serialization::writePod(os, count);
+  serialization::writePod(file, count);
 
   for (const auto& el : elements) {
     // Only PageLine exists currently
-    serialization::writePod(os, static_cast<uint8_t>(TAG_PageLine));
+    serialization::writePod(file, static_cast<uint8_t>(TAG_PageLine));
-    el->serialize(os);
+    el->serialize(file);
   }
 }
 
-std::unique_ptr<Page> Page::deserialize(std::istream& is) {
+std::unique_ptr<Page> Page::deserialize(File& file) {
   uint8_t version;
-  serialization::readPod(is, version);
+  serialization::readPod(file, version);
   if (version != PAGE_FILE_VERSION) {
     Serial.printf("[%lu] [PGE] Deserialization failed: Unknown version %u\n", millis(), version);
     return nullptr;
@@ -57,14 +57,14 @@ std::unique_ptr<Page> Page::deserialize(std::istream& is) {
   auto page = std::unique_ptr<Page>(new Page());
 
   uint32_t count;
-  serialization::readPod(is, count);
+  serialization::readPod(file, count);
 
   for (uint32_t i = 0; i < count; i++) {
     uint8_t tag;
-    serialization::readPod(is, tag);
+    serialization::readPod(file, tag);
 
     if (tag == TAG_PageLine) {
-      auto pl = PageLine::deserialize(is);
+      auto pl = PageLine::deserialize(file);
       page->elements.push_back(std::move(pl));
     } else {
       Serial.printf("[%lu] [PGE] Deserialization failed: Unknown tag %u\n", millis(), tag);

lib/Epub/Epub/Page.h

@@ -1,4 +1,6 @@
 #pragma once
+#include <FS.h>
+
 #include <utility>
 #include <vector>
 
@@ -16,7 +18,7 @@ class PageElement {
   explicit PageElement(const int16_t xPos, const int16_t yPos) : xPos(xPos), yPos(yPos) {}
   virtual ~PageElement() = default;
   virtual void render(GfxRenderer& renderer, int fontId) = 0;
-  virtual void serialize(std::ostream& os) = 0;
+  virtual void serialize(File& file) = 0;
 };
 
 // a line from a block element
@@ -27,8 +29,8 @@ class PageLine final : public PageElement {
   PageLine(std::shared_ptr<TextBlock> block, const int16_t xPos, const int16_t yPos)
       : PageElement(xPos, yPos), block(std::move(block)) {}
   void render(GfxRenderer& renderer, int fontId) override;
-  void serialize(std::ostream& os) override;
+  void serialize(File& file) override;
-  static std::unique_ptr<PageLine> deserialize(std::istream& is);
+  static std::unique_ptr<PageLine> deserialize(File& file);
 };
 
 class Page {
@@ -36,6 +38,6 @@ class Page {
   // the list of block index and line numbers on this page
   std::vector<std::shared_ptr<PageElement>> elements;
   void render(GfxRenderer& renderer, int fontId) const;
-  void serialize(std::ostream& os) const;
+  void serialize(File& file) const;
-  static std::unique_ptr<Page> deserialize(std::istream& is);
+  static std::unique_ptr<Page> deserialize(File& file);
 };

lib/Epub/Epub/ParsedText.cpp

@@ -19,14 +19,25 @@ void ParsedText::addWord(std::string word, const EpdFontStyle fontStyle) {
 
 // Consumes data to minimize memory usage
 void ParsedText::layoutAndExtractLines(const GfxRenderer& renderer, const int fontId, const int horizontalMargin,
-                                       const std::function<void(std::shared_ptr<TextBlock>)>& processLine) {
+                                       const std::function<void(std::shared_ptr<TextBlock>)>& processLine,
+                                       const bool includeLastLine) {
   if (words.empty()) {
     return;
   }
 
-  const size_t totalWordCount = words.size();
   const int pageWidth = renderer.getScreenWidth() - horizontalMargin;
   const int spaceWidth = renderer.getSpaceWidth(fontId);
+  const auto wordWidths = calculateWordWidths(renderer, fontId);
+  const auto lineBreakIndices = computeLineBreaks(pageWidth, spaceWidth, wordWidths);
+  const size_t lineCount = includeLastLine ? lineBreakIndices.size() : lineBreakIndices.size() - 1;
+
+  for (size_t i = 0; i < lineCount; ++i) {
+    extractLine(i, pageWidth, spaceWidth, wordWidths, lineBreakIndices, processLine);
+  }
+}
+
+std::vector<uint16_t> ParsedText::calculateWordWidths(const GfxRenderer& renderer, const int fontId) {
+  const size_t totalWordCount = words.size();
 
   std::vector<uint16_t> wordWidths;
   wordWidths.reserve(totalWordCount);
@@ -47,6 +58,13 @@ void ParsedText::layoutAndExtractLines(const GfxRenderer& renderer, const int fo
     std::advance(wordStylesIt, 1);
   }
 
+  return wordWidths;
+}
+
+std::vector<size_t> ParsedText::computeLineBreaks(const int pageWidth, const int spaceWidth,
+                                                  const std::vector<uint16_t>& wordWidths) const {
+  const size_t totalWordCount = words.size();
+
   // DP table to store the minimum badness (cost) of lines starting at index i
   std::vector<int> dp(totalWordCount);
   // 'ans[i]' stores the index 'j' of the *last word* in the optimal line starting at 'i'
@@ -88,50 +106,58 @@ void ParsedText::layoutAndExtractLines(const GfxRenderer& renderer, const int fo
         ans[i] = j;  // j is the index of the last word in this optimal line
       }
     }
+
+    // Handle oversized word: if no valid configuration found, force single-word line
+    // This prevents cascade failure where one oversized word breaks all preceding words
+    if (dp[i] == MAX_COST) {
+      ans[i] = i;  // Just this word on its own line
+      // Inherit cost from next word to allow subsequent words to find valid configurations
+      if (i + 1 < static_cast<int>(totalWordCount)) {
+        dp[i] = dp[i + 1];
+      } else {
+        dp[i] = 0;
+      }
+    }
   }
 
   // Stores the index of the word that starts the next line (last_word_index + 1)
   std::vector<size_t> lineBreakIndices;
   size_t currentWordIndex = 0;
-  constexpr size_t MAX_LINES = 1000;
 
   while (currentWordIndex < totalWordCount) {
-    if (lineBreakIndices.size() >= MAX_LINES) {
+    size_t nextBreakIndex = ans[currentWordIndex] + 1;
-      break;
+
+    // Safety check: prevent infinite loop if nextBreakIndex doesn't advance
+    if (nextBreakIndex <= currentWordIndex) {
+      // Force advance by at least one word to avoid infinite loop
+      nextBreakIndex = currentWordIndex + 1;
     }
 
-    size_t nextBreakIndex = ans[currentWordIndex] + 1;
     lineBreakIndices.push_back(nextBreakIndex);
-
     currentWordIndex = nextBreakIndex;
   }
 
-  // Initialize iterators for consumption
+  return lineBreakIndices;
-  auto wordStartIt = words.begin();
+}
-  auto wordStyleStartIt = wordStyles.begin();
-  size_t wordWidthIndex = 0;
 
-  size_t lastBreakAt = 0;
+void ParsedText::extractLine(const size_t breakIndex, const int pageWidth, const int spaceWidth,
-  for (const size_t lineBreak : lineBreakIndices) {
+                             const std::vector<uint16_t>& wordWidths, const std::vector<size_t>& lineBreakIndices,
+                             const std::function<void(std::shared_ptr<TextBlock>)>& processLine) {
+  const size_t lineBreak = lineBreakIndices[breakIndex];
+  const size_t lastBreakAt = breakIndex > 0 ? lineBreakIndices[breakIndex - 1] : 0;
   const size_t lineWordCount = lineBreak - lastBreakAt;
 
-    // Calculate end iterators for the range to splice
-    auto wordEndIt = wordStartIt;
-    auto wordStyleEndIt = wordStyleStartIt;
-    std::advance(wordEndIt, lineWordCount);
-    std::advance(wordStyleEndIt, lineWordCount);
-
   // Calculate total word width for this line
   int lineWordWidthSum = 0;
-    for (size_t i = 0; i < lineWordCount; ++i) {
+  for (size_t i = lastBreakAt; i < lineBreak; i++) {
-      lineWordWidthSum += wordWidths[wordWidthIndex + i];
+    lineWordWidthSum += wordWidths[i];
   }
 
   // Calculate spacing
-    int spareSpace = pageWidth - lineWordWidthSum;
+  const int spareSpace = pageWidth - lineWordWidthSum;
 
   int spacing = spaceWidth;
-    const bool isLastLine = lineBreak == totalWordCount;
+  const bool isLastLine = breakIndex == lineBreakIndices.size() - 1;
 
   if (style == TextBlock::JUSTIFIED && !isLastLine && lineWordCount >= 2) {
     spacing = spareSpace / (lineWordCount - 1);
@@ -147,25 +173,23 @@ void ParsedText::layoutAndExtractLines(const GfxRenderer& renderer, const int fo
 
   // Pre-calculate X positions for words
   std::list<uint16_t> lineXPos;
-    for (size_t i = 0; i < lineWordCount; ++i) {
+  for (size_t i = lastBreakAt; i < lineBreak; i++) {
-      const uint16_t currentWordWidth = wordWidths[wordWidthIndex + i];
+    const uint16_t currentWordWidth = wordWidths[i];
     lineXPos.push_back(xpos);
     xpos += currentWordWidth + spacing;
   }
 
+  // Iterators always start at the beginning as we are moving content with splice below
+  auto wordEndIt = words.begin();
+  auto wordStyleEndIt = wordStyles.begin();
+  std::advance(wordEndIt, lineWordCount);
+  std::advance(wordStyleEndIt, lineWordCount);
+
   // *** CRITICAL STEP: CONSUME DATA USING SPLICE ***
   std::list<std::string> lineWords;
-    lineWords.splice(lineWords.begin(), words, wordStartIt, wordEndIt);
+  lineWords.splice(lineWords.begin(), words, words.begin(), wordEndIt);
   std::list<EpdFontStyle> lineWordStyles;
-    lineWordStyles.splice(lineWordStyles.begin(), wordStyles, wordStyleStartIt, wordStyleEndIt);
+  lineWordStyles.splice(lineWordStyles.begin(), wordStyles, wordStyles.begin(), wordStyleEndIt);
 
-    processLine(
+  processLine(std::make_shared<TextBlock>(std::move(lineWords), std::move(lineXPos), std::move(lineWordStyles), style));
-        std::make_shared<TextBlock>(std::move(lineWords), std::move(lineXPos), std::move(lineWordStyles), style));
-
-    // Update pointers/indices for the next line
-    wordStartIt = wordEndIt;
-    wordStyleStartIt = wordStyleEndIt;
-    wordWidthIndex += lineWordCount;
-    lastBreakAt = lineBreak;
-  }
 }

lib/Epub/Epub/ParsedText.h

@@ -2,11 +2,11 @@
 
 #include <EpdFontFamily.h>
 
-#include <cstdint>
 #include <functional>
 #include <list>
 #include <memory>
 #include <string>
+#include <vector>
 
 #include "blocks/TextBlock.h"
 
@@ -18,6 +18,12 @@ class ParsedText {
   TextBlock::BLOCK_STYLE style;
   bool extraParagraphSpacing;
 
+  std::vector<size_t> computeLineBreaks(int pageWidth, int spaceWidth, const std::vector<uint16_t>& wordWidths) const;
+  void extractLine(size_t breakIndex, int pageWidth, int spaceWidth, const std::vector<uint16_t>& wordWidths,
+                   const std::vector<size_t>& lineBreakIndices,
+                   const std::function<void(std::shared_ptr<TextBlock>)>& processLine);
+  std::vector<uint16_t> calculateWordWidths(const GfxRenderer& renderer, int fontId);
+
  public:
   explicit ParsedText(const TextBlock::BLOCK_STYLE style, const bool extraParagraphSpacing)
       : style(style), extraParagraphSpacing(extraParagraphSpacing) {}
@@ -26,7 +32,9 @@ class ParsedText {
   void addWord(std::string word, EpdFontStyle fontStyle);
   void setStyle(const TextBlock::BLOCK_STYLE style) { this->style = style; }
   TextBlock::BLOCK_STYLE getStyle() const { return style; }
+  size_t size() const { return words.size(); }
   bool isEmpty() const { return words.empty(); }
   void layoutAndExtractLines(const GfxRenderer& renderer, int fontId, int horizontalMargin,
-                             const std::function<void(std::shared_ptr<TextBlock>)>& processLine);
+                             const std::function<void(std::shared_ptr<TextBlock>)>& processLine,
+                             bool includeLastLine = true);
 };

lib/Epub/Epub/Section.cpp

@@ -1,11 +1,9 @@
 #include "Section.h"
 
+#include <FsHelpers.h>
 #include <SD.h>
 #include <Serialization.h>
 
-#include <fstream>
-
-#include "FsHelpers.h"
 #include "Page.h"
 #include "parsers/ChapterHtmlSlimParser.h"
 
@@ -16,7 +14,10 @@ constexpr uint8_t SECTION_FILE_VERSION = 6;
 void Section::onPageComplete(std::unique_ptr<Page> page) {
   const auto filePath = cachePath + "/page_" + std::to_string(pageCount) + ".bin";
 
-  std::ofstream outputFile("/sd" + filePath);
+  File outputFile;
+  if (!FsHelpers::openFileForWrite("SCT", filePath, outputFile)) {
+    return;
+  }
   page->serialize(outputFile);
   outputFile.close();
 
@@ -29,7 +30,10 @@ void Section::writeCacheMetadata(const int fontId, const float lineCompression,
                                  const int marginRight, const int marginBottom, const int marginLeft,
                                  const bool extraParagraphSpacing, const int screenWidth,
                                  const int screenHeight) const {
-  std::ofstream outputFile(("/sd" + cachePath + "/section.bin").c_str());
+  File outputFile;
+  if (!FsHelpers::openFileForWrite("SCT", cachePath + "/section.bin", outputFile)) {
+    return;
+  }
   serialization::writePod(outputFile, SECTION_FILE_VERSION);
   serialization::writePod(outputFile, fontId);
   serialization::writePod(outputFile, lineCompression);
@@ -47,17 +51,12 @@ void Section::writeCacheMetadata(const int fontId, const float lineCompression,
 bool Section::loadCacheMetadata(const int fontId, const float lineCompression, const int marginTop,
                                 const int marginRight, const int marginBottom, const int marginLeft,
                                 const bool extraParagraphSpacing, const int screenWidth, const int screenHeight) {
-  if (!SD.exists(cachePath.c_str())) {
-    return false;
-  }
-
   const auto sectionFilePath = cachePath + "/section.bin";
-  if (!SD.exists(sectionFilePath.c_str())) {
+  File inputFile;
+  if (!FsHelpers::openFileForRead("SCT", sectionFilePath, inputFile)) {
     return false;
   }
 
-  std::ifstream inputFile(("/sd" + sectionFilePath).c_str());
-
   // Match parameters
   {
     uint8_t version;
@@ -123,29 +122,57 @@ bool Section::clearCache() const {
 
 bool Section::persistPageDataToSD(const int fontId, const float lineCompression, const int marginTop,
                                   const int marginRight, const int marginBottom, const int marginLeft,
-                                  const bool extraParagraphSpacing, const int screenWidth, const int screenHeight) {
+                                  const bool extraParagraphSpacing, const int screenWidth, const int screenHeight,
-  const auto localPath = epub->getSpineItem(spineIndex);
+                                  const std::function<void()>& progressSetupFn,
-
+                                  const std::function<void(int)>& progressFn) {
-  // TODO: Should we get rid of this file all together?
+  constexpr size_t MIN_SIZE_FOR_PROGRESS = 50 * 1024;  // 50KB
-  //       It currently saves us a bit of memory by allowing for all the inflation bits to be released
+  const auto localPath = epub->getSpineItem(spineIndex).href;
-  //       before loading the XML parser
   const auto tmpHtmlPath = epub->getCachePath() + "/.tmp_" + std::to_string(spineIndex) + ".html";
-  File f = SD.open(tmpHtmlPath.c_str(), FILE_WRITE, true);
+
-  bool success = epub->readItemContentsToStream(localPath, f, 1024);
+  // Retry logic for SD card timing issues
-  f.close();
+  bool success = false;
+  size_t fileSize = 0;
+  for (int attempt = 0; attempt < 3 && !success; attempt++) {
+    if (attempt > 0) {
+      Serial.printf("[%lu] [SCT] Retrying stream (attempt %d)...\n", millis(), attempt + 1);
+      delay(50);  // Brief delay before retry
+    }
+
+    // Remove any incomplete file from previous attempt before retrying
+    if (SD.exists(tmpHtmlPath.c_str())) {
+      SD.remove(tmpHtmlPath.c_str());
+    }
+
+    File tmpHtml;
+    if (!FsHelpers::openFileForWrite("SCT", tmpHtmlPath, tmpHtml)) {
+      continue;
+    }
+    success = epub->readItemContentsToStream(localPath, tmpHtml, 1024);
+    fileSize = tmpHtml.size();
+    tmpHtml.close();
+
+    // If streaming failed, remove the incomplete file immediately
+    if (!success && SD.exists(tmpHtmlPath.c_str())) {
+      SD.remove(tmpHtmlPath.c_str());
+      Serial.printf("[%lu] [SCT] Removed incomplete temp file after failed attempt\n", millis());
+    }
+  }
 
   if (!success) {
-    Serial.printf("[%lu] [SCT] Failed to stream item contents to temp file\n", millis());
+    Serial.printf("[%lu] [SCT] Failed to stream item contents to temp file after retries\n", millis());
     return false;
   }
 
-  Serial.printf("[%lu] [SCT] Streamed temp HTML to %s\n", millis(), tmpHtmlPath.c_str());
+  Serial.printf("[%lu] [SCT] Streamed temp HTML to %s (%d bytes)\n", millis(), tmpHtmlPath.c_str(), fileSize);
 
-  const auto sdTmpHtmlPath = "/sd" + tmpHtmlPath;
+  // Only show progress bar for larger chapters where rendering overhead is worth it
+  if (progressSetupFn && fileSize >= MIN_SIZE_FOR_PROGRESS) {
+    progressSetupFn();
+  }
 
-  ChapterHtmlSlimParser visitor(sdTmpHtmlPath.c_str(), renderer, fontId, lineCompression, marginTop, marginRight,
+  ChapterHtmlSlimParser visitor(
-                                marginBottom, marginLeft, extraParagraphSpacing,
+      tmpHtmlPath, renderer, fontId, lineCompression, marginTop, marginRight, marginBottom, marginLeft,
-                                [this](std::unique_ptr<Page> page) { this->onPageComplete(std::move(page)); });
+      extraParagraphSpacing, [this](std::unique_ptr<Page> page) { this->onPageComplete(std::move(page)); }, progressFn);
   success = visitor.parseAndBuildPages();
 
   SD.remove(tmpHtmlPath.c_str());
@@ -161,13 +188,12 @@ bool Section::persistPageDataToSD(const int fontId, const float lineCompression,
 }
 
 std::unique_ptr<Page> Section::loadPageFromSD() const {
-  const auto filePath = "/sd" + cachePath + "/page_" + std::to_string(currentPage) + ".bin";
+  const auto filePath = cachePath + "/page_" + std::to_string(currentPage) + ".bin";
-  if (!SD.exists(filePath.c_str() + 3)) {
+
-    Serial.printf("[%lu] [SCT] Page file does not exist: %s\n", millis(), filePath.c_str());
+  File inputFile;
+  if (!FsHelpers::openFileForRead("SCT", filePath, inputFile)) {
     return nullptr;
   }
-
-  std::ifstream inputFile(filePath);
   auto page = Page::deserialize(inputFile);
   inputFile.close();
   return page;

lib/Epub/Epub/Section.h

@@ -1,4 +1,5 @@
 #pragma once
+#include <functional>
 #include <memory>
 
 #include "Epub.h"
@@ -21,15 +22,18 @@ class Section {
   int currentPage = 0;
 
   explicit Section(const std::shared_ptr<Epub>& epub, const int spineIndex, GfxRenderer& renderer)
-      : epub(epub), spineIndex(spineIndex), renderer(renderer) {
+      : epub(epub),
-    cachePath = epub->getCachePath() + "/" + std::to_string(spineIndex);
+        spineIndex(spineIndex),
-  }
+        renderer(renderer),
+        cachePath(epub->getCachePath() + "/" + std::to_string(spineIndex)) {}
   ~Section() = default;
   bool loadCacheMetadata(int fontId, float lineCompression, int marginTop, int marginRight, int marginBottom,
                          int marginLeft, bool extraParagraphSpacing, int screenWidth, int screenHeight);
   void setupCacheDir() const;
   bool clearCache() const;
   bool persistPageDataToSD(int fontId, float lineCompression, int marginTop, int marginRight, int marginBottom,
-                           int marginLeft, bool extraParagraphSpacing, int screenWidth, int screenHeight);
+                           int marginLeft, bool extraParagraphSpacing, int screenWidth, int screenHeight,
+                           const std::function<void()>& progressSetupFn = nullptr,
+                           const std::function<void(int)>& progressFn = nullptr);
   std::unique_ptr<Page> loadPageFromSD() const;
 };

lib/Epub/Epub/blocks/TextBlock.cpp

@@ -4,11 +4,18 @@
 #include <Serialization.h>
 
 void TextBlock::render(const GfxRenderer& renderer, const int fontId, const int x, const int y) const {
+  // Validate iterator bounds before rendering
+  if (words.size() != wordXpos.size() || words.size() != wordStyles.size()) {
+    Serial.printf("[%lu] [TXB] Render skipped: size mismatch (words=%u, xpos=%u, styles=%u)\n", millis(),
+                  (uint32_t)words.size(), (uint32_t)wordXpos.size(), (uint32_t)wordStyles.size());
+    return;
+  }
+
   auto wordIt = words.begin();
   auto wordStylesIt = wordStyles.begin();
   auto wordXposIt = wordXpos.begin();
 
-  for (int i = 0; i < words.size(); i++) {
+  for (size_t i = 0; i < words.size(); i++) {
     renderer.drawText(fontId, *wordXposIt + x, y, wordIt->c_str(), true, *wordStylesIt);
 
     std::advance(wordIt, 1);
@@ -17,27 +24,27 @@ void TextBlock::render(const GfxRenderer& renderer, const int fontId, const int
   }
 }
 
-void TextBlock::serialize(std::ostream& os) const {
+void TextBlock::serialize(File& file) const {
   // words
   const uint32_t wc = words.size();
-  serialization::writePod(os, wc);
+  serialization::writePod(file, wc);
-  for (const auto& w : words) serialization::writeString(os, w);
+  for (const auto& w : words) serialization::writeString(file, w);
 
   // wordXpos
   const uint32_t xc = wordXpos.size();
-  serialization::writePod(os, xc);
+  serialization::writePod(file, xc);
-  for (auto x : wordXpos) serialization::writePod(os, x);
+  for (auto x : wordXpos) serialization::writePod(file, x);
 
   // wordStyles
   const uint32_t sc = wordStyles.size();
-  serialization::writePod(os, sc);
+  serialization::writePod(file, sc);
-  for (auto s : wordStyles) serialization::writePod(os, s);
+  for (auto s : wordStyles) serialization::writePod(file, s);
 
   // style
-  serialization::writePod(os, style);
+  serialization::writePod(file, style);
 }
 
-std::unique_ptr<TextBlock> TextBlock::deserialize(std::istream& is) {
+std::unique_ptr<TextBlock> TextBlock::deserialize(File& file) {
   uint32_t wc, xc, sc;
   std::list<std::string> words;
   std::list<uint16_t> wordXpos;
@@ -45,22 +52,36 @@ std::unique_ptr<TextBlock> TextBlock::deserialize(std::istream& is) {
   BLOCK_STYLE style;
 
   // words
-  serialization::readPod(is, wc);
+  serialization::readPod(file, wc);
+
+  // Sanity check: prevent allocation of unreasonably large lists (max 10000 words per block)
+  if (wc > 10000) {
+    Serial.printf("[%lu] [TXB] Deserialization failed: word count %u exceeds maximum\n", millis(), wc);
+    return nullptr;
+  }
+
   words.resize(wc);
-  for (auto& w : words) serialization::readString(is, w);
+  for (auto& w : words) serialization::readString(file, w);
 
   // wordXpos
-  serialization::readPod(is, xc);
+  serialization::readPod(file, xc);
   wordXpos.resize(xc);
-  for (auto& x : wordXpos) serialization::readPod(is, x);
+  for (auto& x : wordXpos) serialization::readPod(file, x);
 
   // wordStyles
-  serialization::readPod(is, sc);
+  serialization::readPod(file, sc);
   wordStyles.resize(sc);
-  for (auto& s : wordStyles) serialization::readPod(is, s);
+  for (auto& s : wordStyles) serialization::readPod(file, s);
+
+  // Validate data consistency: all three lists must have the same size
+  if (wc != xc || wc != sc) {
+    Serial.printf("[%lu] [TXB] Deserialization failed: size mismatch (words=%u, xpos=%u, styles=%u)\n", millis(), wc,
+                  xc, sc);
+    return nullptr;
+  }
 
   // style
-  serialization::readPod(is, style);
+  serialization::readPod(file, style);
 
   return std::unique_ptr<TextBlock>(new TextBlock(std::move(words), std::move(wordXpos), std::move(wordStyles), style));
 }

lib/Epub/Epub/blocks/TextBlock.h

@@ -1,5 +1,6 @@
 #pragma once
 #include <EpdFontFamily.h>
+#include <FS.h>
 
 #include <list>
 #include <memory>
@@ -35,6 +36,6 @@ class TextBlock final : public Block {
   // given a renderer works out where to break the words into lines
   void render(const GfxRenderer& renderer, int fontId, int x, int y) const;
   BlockType getType() override { return TEXT_BLOCK; }
-  void serialize(std::ostream& os) const;
+  void serialize(File& file) const;
-  static std::unique_ptr<TextBlock> deserialize(std::istream& is);
+  static std::unique_ptr<TextBlock> deserialize(File& file);
 };

lib/Epub/Epub/parsers/ChapterHtmlSlimParser.cpp

@@ -1,5 +1,6 @@
 #include "ChapterHtmlSlimParser.h"
 
+#include <FsHelpers.h>
 #include <GfxRenderer.h>
 #include <HardwareSerial.h>
 #include <expat.h>
@@ -10,13 +11,16 @@
 const char* HEADER_TAGS[] = {"h1", "h2", "h3", "h4", "h5", "h6"};
 constexpr int NUM_HEADER_TAGS = sizeof(HEADER_TAGS) / sizeof(HEADER_TAGS[0]);
 
-const char* BLOCK_TAGS[] = {"p", "li", "div", "br"};
+// Minimum file size (in bytes) to show progress bar - smaller chapters don't benefit from it
+constexpr size_t MIN_SIZE_FOR_PROGRESS = 50 * 1024;  // 50KB
+
+const char* BLOCK_TAGS[] = {"p", "li", "div", "br", "blockquote"};
 constexpr int NUM_BLOCK_TAGS = sizeof(BLOCK_TAGS) / sizeof(BLOCK_TAGS[0]);
 
-const char* BOLD_TAGS[] = {"b"};
+const char* BOLD_TAGS[] = {"b", "strong"};
 constexpr int NUM_BOLD_TAGS = sizeof(BOLD_TAGS) / sizeof(BOLD_TAGS[0]);
 
-const char* ITALIC_TAGS[] = {"i"};
+const char* ITALIC_TAGS[] = {"i", "em"};
 constexpr int NUM_ITALIC_TAGS = sizeof(ITALIC_TAGS) / sizeof(ITALIC_TAGS[0]);
 
 const char* IMAGE_TAGS[] = {"img"};
@@ -143,6 +147,17 @@ void XMLCALL ChapterHtmlSlimParser::characterData(void* userData, const XML_Char
 
     self->partWordBuffer[self->partWordBufferIndex++] = s[i];
   }
+
+  // If we have > 750 words buffered up, perform the layout and consume out all but the last line
+  // There should be enough here to build out 1-2 full pages and doing this will free up a lot of
+  // memory.
+  // Spotted when reading Intermezzo, there are some really long text blocks in there.
+  if (self->currentTextBlock->size() > 750) {
+    Serial.printf("[%lu] [EHP] Text block too long, splitting into multiple pages\n", millis());
+    self->currentTextBlock->layoutAndExtractLines(
+        self->renderer, self->fontId, self->marginLeft + self->marginRight,
+        [self](const std::shared_ptr<TextBlock>& textBlock) { self->addLineToPage(textBlock); }, false);
+  }
 }
 
 void XMLCALL ChapterHtmlSlimParser::endElement(void* userData, const XML_Char* name) {
@@ -203,48 +218,75 @@ bool ChapterHtmlSlimParser::parseAndBuildPages() {
     return false;
   }
 
-  XML_SetUserData(parser, this);
+  File file;
-  XML_SetElementHandler(parser, startElement, endElement);
+  if (!FsHelpers::openFileForRead("EHP", filepath, file)) {
-  XML_SetCharacterDataHandler(parser, characterData);
-
-  FILE* file = fopen(filepath, "r");
-  if (!file) {
-    Serial.printf("[%lu] [EHP] Couldn't open file %s\n", millis(), filepath);
     XML_ParserFree(parser);
     return false;
   }
 
+  // Get file size for progress calculation
+  const size_t totalSize = file.size();
+  size_t bytesRead = 0;
+  int lastProgress = -1;
+
+  XML_SetUserData(parser, this);
+  XML_SetElementHandler(parser, startElement, endElement);
+  XML_SetCharacterDataHandler(parser, characterData);
+
   do {
     void* const buf = XML_GetBuffer(parser, 1024);
     if (!buf) {
       Serial.printf("[%lu] [EHP] Couldn't allocate memory for buffer\n", millis());
+      XML_StopParser(parser, XML_FALSE);                // Stop any pending processing
+      XML_SetElementHandler(parser, nullptr, nullptr);  // Clear callbacks
+      XML_SetCharacterDataHandler(parser, nullptr);
       XML_ParserFree(parser);
-      fclose(file);
+      file.close();
       return false;
     }
 
-    const size_t len = fread(buf, 1, 1024, file);
+    const size_t len = file.read(static_cast<uint8_t*>(buf), 1024);
 
-    if (ferror(file)) {
+    if (len == 0) {
       Serial.printf("[%lu] [EHP] File read error\n", millis());
+      XML_StopParser(parser, XML_FALSE);                // Stop any pending processing
+      XML_SetElementHandler(parser, nullptr, nullptr);  // Clear callbacks
+      XML_SetCharacterDataHandler(parser, nullptr);
       XML_ParserFree(parser);
-      fclose(file);
+      file.close();
       return false;
     }
 
-    done = feof(file);
+    // Update progress (call every 10% change to avoid too frequent updates)
+    // Only show progress for larger chapters where rendering overhead is worth it
+    bytesRead += len;
+    if (progressFn && totalSize >= MIN_SIZE_FOR_PROGRESS) {
+      const int progress = static_cast<int>((bytesRead * 100) / totalSize);
+      if (lastProgress / 10 != progress / 10) {
+        lastProgress = progress;
+        progressFn(progress);
+      }
+    }
+
+    done = file.available() == 0;
 
     if (XML_ParseBuffer(parser, static_cast<int>(len), done) == XML_STATUS_ERROR) {
       Serial.printf("[%lu] [EHP] Parse error at line %lu:\n%s\n", millis(), XML_GetCurrentLineNumber(parser),
                     XML_ErrorString(XML_GetErrorCode(parser)));
+      XML_StopParser(parser, XML_FALSE);                // Stop any pending processing
+      XML_SetElementHandler(parser, nullptr, nullptr);  // Clear callbacks
+      XML_SetCharacterDataHandler(parser, nullptr);
       XML_ParserFree(parser);
-      fclose(file);
+      file.close();
       return false;
     }
   } while (!done);
 
+  XML_StopParser(parser, XML_FALSE);                // Stop any pending processing
+  XML_SetElementHandler(parser, nullptr, nullptr);  // Clear callbacks
+  XML_SetCharacterDataHandler(parser, nullptr);
   XML_ParserFree(parser);
-  fclose(file);
+  file.close();
 
   // Process last page if there is still text
   if (currentTextBlock) {

lib/Epub/Epub/parsers/ChapterHtmlSlimParser.h

@@ -15,9 +15,10 @@ class GfxRenderer;
 #define MAX_WORD_SIZE 200
 
 class ChapterHtmlSlimParser {
-  const char* filepath;
+  const std::string& filepath;
   GfxRenderer& renderer;
   std::function<void(std::unique_ptr<Page>)> completePageFn;
+  std::function<void(int)> progressFn;  // Progress callback (0-100)
   int depth = 0;
   int skipUntilDepth = INT_MAX;
   int boldUntilDepth = INT_MAX;
@@ -45,10 +46,11 @@ class ChapterHtmlSlimParser {
   static void XMLCALL endElement(void* userData, const XML_Char* name);
 
  public:
-  explicit ChapterHtmlSlimParser(const char* filepath, GfxRenderer& renderer, const int fontId,
+  explicit ChapterHtmlSlimParser(const std::string& filepath, GfxRenderer& renderer, const int fontId,
                                  const float lineCompression, const int marginTop, const int marginRight,
                                  const int marginBottom, const int marginLeft, const bool extraParagraphSpacing,
-                                 const std::function<void(std::unique_ptr<Page>)>& completePageFn)
+                                 const std::function<void(std::unique_ptr<Page>)>& completePageFn,
+                                 const std::function<void(int)>& progressFn = nullptr)
       : filepath(filepath),
         renderer(renderer),
         fontId(fontId),
@@ -58,7 +60,8 @@ class ChapterHtmlSlimParser {
         marginBottom(marginBottom),
         marginLeft(marginLeft),
         extraParagraphSpacing(extraParagraphSpacing),
-        completePageFn(completePageFn) {}
+        completePageFn(completePageFn),
+        progressFn(progressFn) {}
   ~ChapterHtmlSlimParser() = default;
   bool parseAndBuildPages();
   void addLineToPage(std::shared_ptr<TextBlock> line);

lib/Epub/Epub/parsers/ContainerParser.cpp

@@ -14,12 +14,13 @@ bool ContainerParser::setup() {
   return true;
 }
 
-bool ContainerParser::teardown() {
+ContainerParser::~ContainerParser() {
   if (parser) {
+    XML_StopParser(parser, XML_FALSE);                // Stop any pending processing
+    XML_SetElementHandler(parser, nullptr, nullptr);  // Clear callbacks
     XML_ParserFree(parser);
     parser = nullptr;
   }
-  return true;
 }
 
 size_t ContainerParser::write(const uint8_t data) { return write(&data, 1); }

lib/Epub/Epub/parsers/ContainerParser.h

@@ -23,9 +23,9 @@ class ContainerParser final : public Print {
   std::string fullPath;
 
   explicit ContainerParser(const size_t xmlSize) : remainingSize(xmlSize) {}
+  ~ContainerParser() override;
 
   bool setup();
-  bool teardown();
 
   size_t write(uint8_t) override;
   size_t write(const uint8_t* buffer, size_t size) override;

lib/Epub/Epub/parsers/ContentOpfParser.cpp

@@ -1,11 +1,16 @@
 #include "ContentOpfParser.h"
 
+#include <FsHelpers.h>
 #include <HardwareSerial.h>
+#include <Serialization.h>
 #include <ZipFile.h>
 
+#include "../BookMetadataCache.h"
+
 namespace {
-constexpr const char MEDIA_TYPE_NCX[] = "application/x-dtbncx+xml";
+constexpr char MEDIA_TYPE_NCX[] = "application/x-dtbncx+xml";
-}
+constexpr char itemCacheFile[] = "/.items.bin";
+}  // namespace
 
 bool ContentOpfParser::setup() {
   parser = XML_ParserCreate(nullptr);
@@ -20,12 +25,20 @@ bool ContentOpfParser::setup() {
   return true;
 }
 
-bool ContentOpfParser::teardown() {
+ContentOpfParser::~ContentOpfParser() {
   if (parser) {
+    XML_StopParser(parser, XML_FALSE);                // Stop any pending processing
+    XML_SetElementHandler(parser, nullptr, nullptr);  // Clear callbacks
+    XML_SetCharacterDataHandler(parser, nullptr);
     XML_ParserFree(parser);
     parser = nullptr;
   }
-  return true;
+  if (tempItemStore) {
+    tempItemStore.close();
+  }
+  if (SD.exists((cachePath + itemCacheFile).c_str())) {
+    SD.remove((cachePath + itemCacheFile).c_str());
+  }
 }
 
 size_t ContentOpfParser::write(const uint8_t data) { return write(&data, 1); }
@@ -41,6 +54,9 @@ size_t ContentOpfParser::write(const uint8_t* buffer, const size_t size) {
 
     if (!buf) {
       Serial.printf("[%lu] [COF] Couldn't allocate memory for buffer\n", millis());
+      XML_StopParser(parser, XML_FALSE);                // Stop any pending processing
+      XML_SetElementHandler(parser, nullptr, nullptr);  // Clear callbacks
+      XML_SetCharacterDataHandler(parser, nullptr);
       XML_ParserFree(parser);
       parser = nullptr;
       return 0;
@@ -52,6 +68,9 @@ size_t ContentOpfParser::write(const uint8_t* buffer, const size_t size) {
     if (XML_ParseBuffer(parser, static_cast<int>(toRead), remainingSize == toRead) == XML_STATUS_ERROR) {
       Serial.printf("[%lu] [COF] Parse error at line %lu: %s\n", millis(), XML_GetCurrentLineNumber(parser),
                     XML_ErrorString(XML_GetErrorCode(parser)));
+      XML_StopParser(parser, XML_FALSE);                // Stop any pending processing
+      XML_SetElementHandler(parser, nullptr, nullptr);  // Clear callbacks
+      XML_SetCharacterDataHandler(parser, nullptr);
       XML_ParserFree(parser);
       parser = nullptr;
       return 0;
@@ -86,11 +105,21 @@ void XMLCALL ContentOpfParser::startElement(void* userData, const XML_Char* name
 
   if (self->state == IN_PACKAGE && (strcmp(name, "manifest") == 0 || strcmp(name, "opf:manifest") == 0)) {
     self->state = IN_MANIFEST;
+    if (!FsHelpers::openFileForWrite("COF", self->cachePath + itemCacheFile, self->tempItemStore)) {
+      Serial.printf(
+          "[%lu] [COF] Couldn't open temp items file for writing. This is probably going to be a fatal error.\n",
+          millis());
+    }
     return;
   }
 
   if (self->state == IN_PACKAGE && (strcmp(name, "spine") == 0 || strcmp(name, "opf:spine") == 0)) {
     self->state = IN_SPINE;
+    if (!FsHelpers::openFileForRead("COF", self->cachePath + itemCacheFile, self->tempItemStore)) {
+      Serial.printf(
+          "[%lu] [COF] Couldn't open temp items file for reading. This is probably going to be a fatal error.\n",
+          millis());
+    }
     return;
   }
 
@@ -127,7 +156,13 @@ void XMLCALL ContentOpfParser::startElement(void* userData, const XML_Char* name
       }
     }
 
-    self->items[itemId] = href;
+    // Write items down to SD card
+    serialization::writeString(self->tempItemStore, itemId);
+    serialization::writeString(self->tempItemStore, href);
+
+    if (itemId == self->coverItemId) {
+      self->coverItemHref = href;
+    }
 
     if (mediaType == MEDIA_TYPE_NCX) {
       if (self->tocNcxPath.empty()) {
@@ -140,15 +175,30 @@ void XMLCALL ContentOpfParser::startElement(void* userData, const XML_Char* name
     return;
   }
 
+  // NOTE: This relies on spine appearing after item manifest (which is pretty safe as it's part of the EPUB spec)
+  // Only run the spine parsing if there's a cache to add it to
+  if (self->cache) {
     if (self->state == IN_SPINE && (strcmp(name, "itemref") == 0 || strcmp(name, "opf:itemref") == 0)) {
       for (int i = 0; atts[i]; i += 2) {
         if (strcmp(atts[i], "idref") == 0) {
-        self->spineRefs.emplace_back(atts[i + 1]);
+          const std::string idref = atts[i + 1];
+          // Resolve the idref to href using items map
+          self->tempItemStore.seek(0);
+          std::string itemId;
+          std::string href;
+          while (self->tempItemStore.available()) {
+            serialization::readString(self->tempItemStore, itemId);
+            serialization::readString(self->tempItemStore, href);
+            if (itemId == idref) {
+              self->cache->createSpineEntry(href);
               break;
             }
           }
+        }
+      }
       return;
     }
+  }
 }
 
 void XMLCALL ContentOpfParser::characterData(void* userData, const XML_Char* s, const int len) {
@@ -166,11 +216,13 @@ void XMLCALL ContentOpfParser::endElement(void* userData, const XML_Char* name)
 
   if (self->state == IN_SPINE && (strcmp(name, "spine") == 0 || strcmp(name, "opf:spine") == 0)) {
     self->state = IN_PACKAGE;
+    self->tempItemStore.close();
     return;
   }
 
   if (self->state == IN_MANIFEST && (strcmp(name, "manifest") == 0 || strcmp(name, "opf:manifest") == 0)) {
     self->state = IN_PACKAGE;
+    self->tempItemStore.close();
     return;
   }
 

lib/Epub/Epub/parsers/ContentOpfParser.h

@@ -1,11 +1,11 @@
 #pragma once
 #include <Print.h>
 
-#include <map>
-
 #include "Epub.h"
 #include "expat.h"
 
+class BookMetadataCache;
+
 class ContentOpfParser final : public Print {
   enum ParserState {
     START,
@@ -16,10 +16,14 @@ class ContentOpfParser final : public Print {
     IN_SPINE,
   };
 
+  const std::string& cachePath;
   const std::string& baseContentPath;
   size_t remainingSize;
   XML_Parser parser = nullptr;
   ParserState state = START;
+  BookMetadataCache* cache;
+  File tempItemStore;
+  std::string coverItemId;
 
   static void startElement(void* userData, const XML_Char* name, const XML_Char** atts);
   static void characterData(void* userData, const XML_Char* s, int len);
@@ -28,15 +32,14 @@ class ContentOpfParser final : public Print {
  public:
   std::string title;
   std::string tocNcxPath;
-  std::string coverItemId;
+  std::string coverItemHref;
-  std::map<std::string, std::string> items;
-  std::vector<std::string> spineRefs;
 
-  explicit ContentOpfParser(const std::string& baseContentPath, const size_t xmlSize)
+  explicit ContentOpfParser(const std::string& cachePath, const std::string& baseContentPath, const size_t xmlSize,
-      : baseContentPath(baseContentPath), remainingSize(xmlSize) {}
+                            BookMetadataCache* cache)
+      : cachePath(cachePath), baseContentPath(baseContentPath), remainingSize(xmlSize), cache(cache) {}
+  ~ContentOpfParser() override;
 
   bool setup();
-  bool teardown();
 
   size_t write(uint8_t) override;
   size_t write(const uint8_t* buffer, size_t size) override;

lib/Epub/Epub/parsers/TocNcxParser.cpp

@@ -2,6 +2,8 @@
 
 #include <HardwareSerial.h>
 
+#include "../BookMetadataCache.h"
+
 bool TocNcxParser::setup() {
   parser = XML_ParserCreate(nullptr);
   if (!parser) {
@@ -15,12 +17,14 @@ bool TocNcxParser::setup() {
   return true;
 }
 
-bool TocNcxParser::teardown() {
+TocNcxParser::~TocNcxParser() {
   if (parser) {
+    XML_StopParser(parser, XML_FALSE);                // Stop any pending processing
+    XML_SetElementHandler(parser, nullptr, nullptr);  // Clear callbacks
+    XML_SetCharacterDataHandler(parser, nullptr);
     XML_ParserFree(parser);
     parser = nullptr;
   }
-  return true;
 }
 
 size_t TocNcxParser::write(const uint8_t data) { return write(&data, 1); }
@@ -35,6 +39,11 @@ size_t TocNcxParser::write(const uint8_t* buffer, const size_t size) {
     void* const buf = XML_GetBuffer(parser, 1024);
     if (!buf) {
       Serial.printf("[%lu] [TOC] Couldn't allocate memory for buffer\n", millis());
+      XML_StopParser(parser, XML_FALSE);                // Stop any pending processing
+      XML_SetElementHandler(parser, nullptr, nullptr);  // Clear callbacks
+      XML_SetCharacterDataHandler(parser, nullptr);
+      XML_ParserFree(parser);
+      parser = nullptr;
       return 0;
     }
 
@@ -44,6 +53,11 @@ size_t TocNcxParser::write(const uint8_t* buffer, const size_t size) {
     if (XML_ParseBuffer(parser, static_cast<int>(toRead), remainingSize == toRead) == XML_STATUS_ERROR) {
       Serial.printf("[%lu] [TOC] Parse error at line %lu: %s\n", millis(), XML_GetCurrentLineNumber(parser),
                     XML_ErrorString(XML_GetErrorCode(parser)));
+      XML_StopParser(parser, XML_FALSE);                // Stop any pending processing
+      XML_SetElementHandler(parser, nullptr, nullptr);  // Clear callbacks
+      XML_SetCharacterDataHandler(parser, nullptr);
+      XML_ParserFree(parser);
+      parser = nullptr;
       return 0;
     }
 
@@ -154,8 +168,9 @@ void XMLCALL TocNcxParser::endElement(void* userData, const XML_Char* name) {
         href = href.substr(0, pos);
       }
 
-      // Push to vector
+      if (self->cache) {
-      self->toc.emplace_back(self->currentLabel, href, anchor, self->currentDepth);
+        self->cache->createTocEntry(self->currentLabel, href, anchor, self->currentDepth);
+      }
 
       // Clear them so we don't re-add them if there are weird XML structures
       self->currentLabel.clear();

lib/Epub/Epub/parsers/TocNcxParser.h

@@ -1,11 +1,10 @@
 #pragma once
 #include <Print.h>
+#include <expat.h>
 
 #include <string>
-#include <vector>
 
-#include "Epub/EpubTocEntry.h"
+class BookMetadataCache;
-#include "expat.h"
 
 class TocNcxParser final : public Print {
   enum ParserState { START, IN_NCX, IN_NAV_MAP, IN_NAV_POINT, IN_NAV_LABEL, IN_NAV_LABEL_TEXT, IN_CONTENT };
@@ -14,23 +13,22 @@ class TocNcxParser final : public Print {
   size_t remainingSize;
   XML_Parser parser = nullptr;
   ParserState state = START;
+  BookMetadataCache* cache;
 
   std::string currentLabel;
   std::string currentSrc;
-  size_t currentDepth = 0;
+  uint8_t currentDepth = 0;
 
   static void startElement(void* userData, const XML_Char* name, const XML_Char** atts);
   static void characterData(void* userData, const XML_Char* s, int len);
   static void endElement(void* userData, const XML_Char* name);
 
  public:
-  std::vector<EpubTocEntry> toc;
+  explicit TocNcxParser(const std::string& baseContentPath, const size_t xmlSize, BookMetadataCache* cache)
-
+      : baseContentPath(baseContentPath), remainingSize(xmlSize), cache(cache) {}
-  explicit TocNcxParser(const std::string& baseContentPath, const size_t xmlSize)
+  ~TocNcxParser() override;
-      : baseContentPath(baseContentPath), remainingSize(xmlSize) {}
 
   bool setup();
-  bool teardown();
 
   size_t write(uint8_t) override;
   size_t write(const uint8_t* buffer, size_t size) override;

lib/FsHelpers/FsHelpers.cpp

@@ -0,0 +1,112 @@
+#include "FsHelpers.h"
+
+#include <SD.h>
+
+#include <vector>
+
+bool FsHelpers::openFileForRead(const char* moduleName, const char* path, File& file) {
+  if (!SD.exists(path)) {
+    return false;
+  }
+
+  file = SD.open(path, FILE_READ);
+  if (!file) {
+    Serial.printf("[%lu] [%s] Failed to open file for reading: %s\n", millis(), moduleName, path);
+    return false;
+  }
+  return true;
+}
+
+bool FsHelpers::openFileForRead(const char* moduleName, const std::string& path, File& file) {
+  return openFileForRead(moduleName, path.c_str(), file);
+}
+
+bool FsHelpers::openFileForRead(const char* moduleName, const String& path, File& file) {
+  return openFileForRead(moduleName, path.c_str(), file);
+}
+
+bool FsHelpers::openFileForWrite(const char* moduleName, const char* path, File& file) {
+  file = SD.open(path, FILE_WRITE, true);
+  if (!file) {
+    Serial.printf("[%lu] [%s] Failed to open file for writing: %s\n", millis(), moduleName, path);
+    return false;
+  }
+  return true;
+}
+
+bool FsHelpers::openFileForWrite(const char* moduleName, const std::string& path, File& file) {
+  return openFileForWrite(moduleName, path.c_str(), file);
+}
+
+bool FsHelpers::openFileForWrite(const char* moduleName, const String& path, File& file) {
+  return openFileForWrite(moduleName, path.c_str(), file);
+}
+
+bool FsHelpers::removeDir(const char* path) {
+  // 1. Open the directory
+  File dir = SD.open(path);
+  if (!dir) {
+    return false;
+  }
+  if (!dir.isDirectory()) {
+    return false;
+  }
+
+  File file = dir.openNextFile();
+  while (file) {
+    String filePath = path;
+    if (!filePath.endsWith("/")) {
+      filePath += "/";
+    }
+    filePath += file.name();
+
+    if (file.isDirectory()) {
+      if (!removeDir(filePath.c_str())) {
+        return false;
+      }
+    } else {
+      if (!SD.remove(filePath.c_str())) {
+        return false;
+      }
+    }
+    file = dir.openNextFile();
+  }
+
+  return SD.rmdir(path);
+}
+
+std::string FsHelpers::normalisePath(const std::string& path) {
+  std::vector<std::string> components;
+  std::string component;
+
+  for (const auto c : path) {
+    if (c == '/') {
+      if (!component.empty()) {
+        if (component == "..") {
+          if (!components.empty()) {
+            components.pop_back();
+          }
+        } else {
+          components.push_back(component);
+        }
+        component.clear();
+      }
+    } else {
+      component += c;
+    }
+  }
+
+  if (!component.empty()) {
+    components.push_back(component);
+  }
+
+  std::string result;
+  for (const auto& c : components) {
+    if (!result.empty()) {
+      result += "/";
+    }
+    result += c;
+  }
+
+  return result;
+}

lib/FsHelpers/FsHelpers.h

@@ -0,0 +1,14 @@
+#pragma once
+#include <FS.h>
+
+class FsHelpers {
+ public:
+  static bool openFileForRead(const char* moduleName, const char* path, File& file);
+  static bool openFileForRead(const char* moduleName, const std::string& path, File& file);
+  static bool openFileForRead(const char* moduleName, const String& path, File& file);
+  static bool openFileForWrite(const char* moduleName, const char* path, File& file);
+  static bool openFileForWrite(const char* moduleName, const std::string& path, File& file);
+  static bool openFileForWrite(const char* moduleName, const String& path, File& file);
+  static bool removeDir(const char* path);
+  static std::string normalisePath(const std::string& path);
+};

lib/GfxRenderer/Bitmap.cpp

@@ -3,6 +3,126 @@
 #include <cstdlib>
 #include <cstring>
 
+// ============================================================================
+// IMAGE PROCESSING OPTIONS - Toggle these to test different configurations
+// ============================================================================
+// Note: For cover images, dithering is done in JpegToBmpConverter.cpp
+// This file handles BMP reading - use simple quantization to avoid double-dithering
+constexpr bool USE_FLOYD_STEINBERG = false;  // Disabled - dithering done at JPEG conversion
+constexpr bool USE_NOISE_DITHERING = false;  // Hash-based noise dithering
+// Brightness adjustments:
+constexpr bool USE_BRIGHTNESS = false;    // true: apply brightness/gamma adjustments
+constexpr int BRIGHTNESS_BOOST = 20;      // Brightness offset (0-50), only if USE_BRIGHTNESS=true
+constexpr bool GAMMA_CORRECTION = false;  // Gamma curve, only if USE_BRIGHTNESS=true
+// ============================================================================
+
+// Integer approximation of gamma correction (brightens midtones)
+static inline int applyGamma(int gray) {
+  if (!GAMMA_CORRECTION) return gray;
+  const int product = gray * 255;
+  int x = gray;
+  if (x > 0) {
+    x = (x + product / x) >> 1;
+    x = (x + product / x) >> 1;
+  }
+  return x > 255 ? 255 : x;
+}
+
+// Simple quantization without dithering - just divide into 4 levels
+static inline uint8_t quantizeSimple(int gray) {
+  if (USE_BRIGHTNESS) {
+    gray += BRIGHTNESS_BOOST;
+    if (gray > 255) gray = 255;
+    gray = applyGamma(gray);
+  }
+  return static_cast<uint8_t>(gray >> 6);
+}
+
+// Hash-based noise dithering - survives downsampling without moiré artifacts
+static inline uint8_t quantizeNoise(int gray, int x, int y) {
+  if (USE_BRIGHTNESS) {
+    gray += BRIGHTNESS_BOOST;
+    if (gray > 255) gray = 255;
+    gray = applyGamma(gray);
+  }
+
+  uint32_t hash = static_cast<uint32_t>(x) * 374761393u + static_cast<uint32_t>(y) * 668265263u;
+  hash = (hash ^ (hash >> 13)) * 1274126177u;
+  const int threshold = static_cast<int>(hash >> 24);
+
+  const int scaled = gray * 3;
+  if (scaled < 255) {
+    return (scaled + threshold >= 255) ? 1 : 0;
+  } else if (scaled < 510) {
+    return ((scaled - 255) + threshold >= 255) ? 2 : 1;
+  } else {
+    return ((scaled - 510) + threshold >= 255) ? 3 : 2;
+  }
+}
+
+// Main quantization function
+static inline uint8_t quantize(int gray, int x, int y) {
+  if (USE_NOISE_DITHERING) {
+    return quantizeNoise(gray, x, y);
+  } else {
+    return quantizeSimple(gray);
+  }
+}
+
+// Floyd-Steinberg quantization with error diffusion and serpentine scanning
+// Returns 2-bit value (0-3) and updates error buffers
+static inline uint8_t quantizeFloydSteinberg(int gray, int x, int width, int16_t* errorCurRow, int16_t* errorNextRow,
+                                             bool reverseDir) {
+  // Add accumulated error to this pixel
+  int adjusted = gray + errorCurRow[x + 1];
+
+  // Clamp to valid range
+  if (adjusted < 0) adjusted = 0;
+  if (adjusted > 255) adjusted = 255;
+
+  // Quantize to 4 levels (0, 85, 170, 255)
+  uint8_t quantized;
+  int quantizedValue;
+  if (adjusted < 43) {
+    quantized = 0;
+    quantizedValue = 0;
+  } else if (adjusted < 128) {
+    quantized = 1;
+    quantizedValue = 85;
+  } else if (adjusted < 213) {
+    quantized = 2;
+    quantizedValue = 170;
+  } else {
+    quantized = 3;
+    quantizedValue = 255;
+  }
+
+  // Calculate error
+  int error = adjusted - quantizedValue;
+
+  // Distribute error to neighbors (serpentine: direction-aware)
+  if (!reverseDir) {
+    // Left to right
+    errorCurRow[x + 2] += (error * 7) >> 4;   // Right: 7/16
+    errorNextRow[x] += (error * 3) >> 4;      // Bottom-left: 3/16
+    errorNextRow[x + 1] += (error * 5) >> 4;  // Bottom: 5/16
+    errorNextRow[x + 2] += (error) >> 4;      // Bottom-right: 1/16
+  } else {
+    // Right to left (mirrored)
+    errorCurRow[x] += (error * 7) >> 4;       // Left: 7/16
+    errorNextRow[x + 2] += (error * 3) >> 4;  // Bottom-right: 3/16
+    errorNextRow[x + 1] += (error * 5) >> 4;  // Bottom: 5/16
+    errorNextRow[x] += (error) >> 4;          // Bottom-left: 1/16
+  }
+
+  return quantized;
+}
+
+Bitmap::~Bitmap() {
+  delete[] errorCurRow;
+  delete[] errorNextRow;
+}
+
 uint16_t Bitmap::readLE16(File& f) {
   const int c0 = f.read();
   const int c1 = f.read();
@@ -46,6 +166,8 @@ const char* Bitmap::errorToString(BmpReaderError err) {
       return "UnsupportedCompression (expected BI_RGB or BI_BITFIELDS for 32bpp)";
     case BmpReaderError::BadDimensions:
       return "BadDimensions";
+    case BmpReaderError::ImageTooLarge:
+      return "ImageTooLarge (max 2048x3072)";
     case BmpReaderError::PaletteTooLarge:
       return "PaletteTooLarge";
 
@@ -99,6 +221,13 @@ BmpReaderError Bitmap::parseHeaders() {
 
   if (width <= 0 || height <= 0) return BmpReaderError::BadDimensions;
 
+  // Safety limits to prevent memory issues on ESP32
+  constexpr int MAX_IMAGE_WIDTH = 2048;
+  constexpr int MAX_IMAGE_HEIGHT = 3072;
+  if (width > MAX_IMAGE_WIDTH || height > MAX_IMAGE_HEIGHT) {
+    return BmpReaderError::ImageTooLarge;
+  }
+
   // Pre-calculate Row Bytes to avoid doing this every row
   rowBytes = (width * bpp + 31) / 32 * 4;
 
@@ -115,21 +244,56 @@ BmpReaderError Bitmap::parseHeaders() {
     return BmpReaderError::SeekPixelDataFailed;
   }
 
+  // Allocate Floyd-Steinberg error buffers if enabled
+  if (USE_FLOYD_STEINBERG) {
+    delete[] errorCurRow;
+    delete[] errorNextRow;
+    errorCurRow = new int16_t[width + 2]();  // +2 for boundary handling
+    errorNextRow = new int16_t[width + 2]();
+    lastRowY = -1;
+  }
+
   return BmpReaderError::Ok;
 }
 
 // packed 2bpp output, 0 = black, 1 = dark gray, 2 = light gray, 3 = white
-BmpReaderError Bitmap::readRow(uint8_t* data, uint8_t* rowBuffer) const {
+BmpReaderError Bitmap::readRow(uint8_t* data, uint8_t* rowBuffer, int rowY) const {
   // Note: rowBuffer should be pre-allocated by the caller to size 'rowBytes'
   if (file.read(rowBuffer, rowBytes) != rowBytes) return BmpReaderError::ShortReadRow;
 
+  // Handle Floyd-Steinberg error buffer progression
+  const bool useFS = USE_FLOYD_STEINBERG && errorCurRow && errorNextRow;
+  if (useFS) {
+    // Check if we need to advance to next row (or reset if jumping)
+    if (rowY != lastRowY + 1 && rowY != 0) {
+      // Non-sequential row access - reset error buffers
+      memset(errorCurRow, 0, (width + 2) * sizeof(int16_t));
+      memset(errorNextRow, 0, (width + 2) * sizeof(int16_t));
+    } else if (rowY > 0) {
+      // Sequential access - swap buffers
+      int16_t* temp = errorCurRow;
+      errorCurRow = errorNextRow;
+      errorNextRow = temp;
+      memset(errorNextRow, 0, (width + 2) * sizeof(int16_t));
+    }
+    lastRowY = rowY;
+  }
+
   uint8_t* outPtr = data;
   uint8_t currentOutByte = 0;
   int bitShift = 6;
+  int currentX = 0;
 
   // Helper lambda to pack 2bpp color into the output stream
-  auto packPixel = [&](uint8_t lum) {
+  auto packPixel = [&](const uint8_t lum) {
-    uint8_t color = (lum >> 6);  // Simple 2-bit reduction: 0-255 -> 0-3
+    uint8_t color;
+    if (useFS) {
+      // Floyd-Steinberg error diffusion
+      color = quantizeFloydSteinberg(lum, currentX, width, errorCurRow, errorNextRow, false);
+    } else {
+      // Simple quantization or noise dithering
+      color = quantize(lum, currentX, rowY);
+    }
     currentOutByte |= (color << bitShift);
     if (bitShift == 0) {
       *outPtr++ = currentOutByte;
@@ -138,40 +302,52 @@ BmpReaderError Bitmap::readRow(uint8_t* data, uint8_t* rowBuffer) const {
     } else {
       bitShift -= 2;
     }
+    currentX++;
   };
 
+  uint8_t lum;
+
   switch (bpp) {
-    case 8: {
+    case 32: {
+      const uint8_t* p = rowBuffer;
       for (int x = 0; x < width; x++) {
-        packPixel(paletteLum[rowBuffer[x]]);
+        lum = (77u * p[2] + 150u * p[1] + 29u * p[0]) >> 8;
+        packPixel(lum);
+        p += 4;
       }
       break;
     }
     case 24: {
       const uint8_t* p = rowBuffer;
       for (int x = 0; x < width; x++) {
-        uint8_t lum = (77u * p[2] + 150u * p[1] + 29u * p[0]) >> 8;
+        lum = (77u * p[2] + 150u * p[1] + 29u * p[0]) >> 8;
         packPixel(lum);
         p += 3;
       }
       break;
     }
+    case 8: {
+      for (int x = 0; x < width; x++) {
+        packPixel(paletteLum[rowBuffer[x]]);
+      }
+      break;
+    }
+    case 2: {
+      for (int x = 0; x < width; x++) {
+        lum = paletteLum[(rowBuffer[x >> 2] >> (6 - ((x & 3) * 2))) & 0x03];
+        packPixel(lum);
+      }
+      break;
+    }
     case 1: {
       for (int x = 0; x < width; x++) {
-        uint8_t lum = (rowBuffer[x >> 3] & (0x80 >> (x & 7))) ? 0xFF : 0x00;
+        lum = (rowBuffer[x >> 3] & (0x80 >> (x & 7))) ? 0xFF : 0x00;
         packPixel(lum);
       }
       break;
     }
-    case 32: {
+    default:
-      const uint8_t* p = rowBuffer;
+      return BmpReaderError::UnsupportedBpp;
-      for (int x = 0; x < width; x++) {
-        uint8_t lum = (77u * p[2] + 150u * p[1] + 29u * p[0]) >> 8;
-        packPixel(lum);
-        p += 4;
-      }
-      break;
-    }
   }
 
   // Flush remaining bits if width is not a multiple of 4
@@ -185,5 +361,12 @@ BmpReaderError Bitmap::rewindToData() const {
     return BmpReaderError::SeekPixelDataFailed;
   }
 
+  // Reset Floyd-Steinberg error buffers when rewinding
+  if (USE_FLOYD_STEINBERG && errorCurRow && errorNextRow) {
+    memset(errorCurRow, 0, (width + 2) * sizeof(int16_t));
+    memset(errorNextRow, 0, (width + 2) * sizeof(int16_t));
+    lastRowY = -1;
+  }
+
   return BmpReaderError::Ok;
 }

lib/GfxRenderer/Bitmap.h

@@ -15,6 +15,7 @@ enum class BmpReaderError : uint8_t {
   UnsupportedCompression,
 
   BadDimensions,
+  ImageTooLarge,
   PaletteTooLarge,
 
   SeekPixelDataFailed,
@@ -28,8 +29,9 @@ class Bitmap {
   static const char* errorToString(BmpReaderError err);
 
   explicit Bitmap(File& file) : file(file) {}
+  ~Bitmap();
   BmpReaderError parseHeaders();
-  BmpReaderError readRow(uint8_t* data, uint8_t* rowBuffer) const;
+  BmpReaderError readRow(uint8_t* data, uint8_t* rowBuffer, int rowY) const;
   BmpReaderError rewindToData() const;
   int getWidth() const { return width; }
   int getHeight() const { return height; }
@@ -49,4 +51,9 @@ class Bitmap {
   uint16_t bpp = 0;
   int rowBytes = 0;
   uint8_t paletteLum[256] = {};
+
+  // Floyd-Steinberg dithering state (mutable for const methods)
+  mutable int16_t* errorCurRow = nullptr;
+  mutable int16_t* errorNextRow = nullptr;
+  mutable int lastRowY = -1;  // Track row progression for error propagation
 };

lib/GfxRenderer/GfxRenderer.cpp

@@ -164,10 +164,19 @@ void GfxRenderer::drawBitmap(const Bitmap& bitmap, const int x, const int y, con
     isScaled = true;
   }
 
-  const uint8_t outputRowSize = (bitmap.getWidth() + 3) / 4;
+  // Calculate output row size (2 bits per pixel, packed into bytes)
+  // IMPORTANT: Use int, not uint8_t, to avoid overflow for images > 1020 pixels wide
+  const int outputRowSize = (bitmap.getWidth() + 3) / 4;
   auto* outputRow = static_cast<uint8_t*>(malloc(outputRowSize));
   auto* rowBytes = static_cast<uint8_t*>(malloc(bitmap.getRowBytes()));
 
+  if (!outputRow || !rowBytes) {
+    Serial.printf("[%lu] [GFX] !! Failed to allocate BMP row buffers\n", millis());
+    free(outputRow);
+    free(rowBytes);
+    return;
+  }
+
   for (int bmpY = 0; bmpY < bitmap.getHeight(); bmpY++) {
     // The BMP's (0, 0) is the bottom-left corner (if the height is positive, top-left if negative).
     // Screen's (0, 0) is the top-left corner.
@@ -179,7 +188,7 @@ void GfxRenderer::drawBitmap(const Bitmap& bitmap, const int x, const int y, con
       break;
     }
 
-    if (bitmap.readRow(outputRow, rowBytes) != BmpReaderError::Ok) {
+    if (bitmap.readRow(outputRow, rowBytes, bmpY) != BmpReaderError::Ok) {
       Serial.printf("[%lu] [GFX] Failed to read row %d from bitmap\n", millis(), bmpY);
       free(outputRow);
       free(rowBytes);
@@ -215,6 +224,10 @@ void GfxRenderer::clearScreen(const uint8_t color) const { einkDisplay.clearScre
 
 void GfxRenderer::invertScreen() const {
   uint8_t* buffer = einkDisplay.getFrameBuffer();
+  if (!buffer) {
+    Serial.printf("[%lu] [GFX] !! No framebuffer in invertScreen\n", millis());
+    return;
+  }
   for (int i = 0; i < EInkDisplay::BUFFER_SIZE; i++) {
     buffer[i] = ~buffer[i];
   }
@@ -293,6 +306,28 @@ int GfxRenderer::getLineHeight(const int fontId) const {
   return fontMap.at(fontId).getData(REGULAR)->advanceY;
 }
 
+void GfxRenderer::drawButtonHints(const int fontId, const char* btn1, const char* btn2, const char* btn3,
+                                  const char* btn4) const {
+  const int pageHeight = getScreenHeight();
+  constexpr int buttonWidth = 106;
+  constexpr int buttonHeight = 40;
+  constexpr int buttonY = 40;     // Distance from bottom
+  constexpr int textYOffset = 5;  // Distance from top of button to text baseline
+  constexpr int buttonPositions[] = {25, 130, 245, 350};
+  const char* labels[] = {btn1, btn2, btn3, btn4};
+
+  for (int i = 0; i < 4; i++) {
+    // Only draw if the label is non-empty
+    if (labels[i] != nullptr && labels[i][0] != '\0') {
+      const int x = buttonPositions[i];
+      drawRect(x, pageHeight - buttonY, buttonWidth, buttonHeight);
+      const int textWidth = getTextWidth(fontId, labels[i]);
+      const int textX = x + (buttonWidth - 1 - textWidth) / 2;
+      drawText(fontId, textX, pageHeight - buttonY + textYOffset, labels[i]);
+    }
+  }
+}
+
 uint8_t* GfxRenderer::getFrameBuffer() const { return einkDisplay.getFrameBuffer(); }
 
 size_t GfxRenderer::getBufferSize() { return EInkDisplay::BUFFER_SIZE; }
@@ -321,6 +356,10 @@ void GfxRenderer::freeBwBufferChunks() {
  */
 void GfxRenderer::storeBwBuffer() {
   const uint8_t* frameBuffer = einkDisplay.getFrameBuffer();
+  if (!frameBuffer) {
+    Serial.printf("[%lu] [GFX] !! No framebuffer in storeBwBuffer\n", millis());
+    return;
+  }
 
   // Allocate and copy each chunk
   for (size_t i = 0; i < BW_BUFFER_NUM_CHUNKS; i++) {
@@ -371,6 +410,12 @@ void GfxRenderer::restoreBwBuffer() {
   }
 
   uint8_t* frameBuffer = einkDisplay.getFrameBuffer();
+  if (!frameBuffer) {
+    Serial.printf("[%lu] [GFX] !! No framebuffer in restoreBwBuffer\n", millis());
+    freeBwBufferChunks();
+    return;
+  }
+
   for (size_t i = 0; i < BW_BUFFER_NUM_CHUNKS; i++) {
     // Check if chunk is missing
     if (!bwBufferChunks[i]) {

lib/GfxRenderer/GfxRenderer.h

@@ -71,6 +71,9 @@ class GfxRenderer {
   int getSpaceWidth(int fontId) const;
   int getLineHeight(int fontId) const;
 
+  // UI Components
+  void drawButtonHints(int fontId, const char* btn1, const char* btn2, const char* btn3, const char* btn4) const;
+
   // Grayscale functions
   void setRenderMode(const RenderMode mode) { this->renderMode = mode; }
   void copyGrayscaleLsbBuffers() const;

lib/JpegToBmpConverter/JpegToBmpConverter.cpp

@@ -0,0 +1,736 @@
+#include "JpegToBmpConverter.h"
+
+#include <picojpeg.h>
+
+#include <cstdio>
+#include <cstring>
+
+// Context structure for picojpeg callback
+struct JpegReadContext {
+  File& file;
+  uint8_t buffer[512];
+  size_t bufferPos;
+  size_t bufferFilled;
+};
+
+// ============================================================================
+// IMAGE PROCESSING OPTIONS - Toggle these to test different configurations
+// ============================================================================
+constexpr bool USE_8BIT_OUTPUT = false;  // true: 8-bit grayscale (no quantization), false: 2-bit (4 levels)
+// Dithering method selection (only one should be true, or all false for simple quantization):
+constexpr bool USE_ATKINSON = true;          // Atkinson dithering (cleaner than F-S, less error diffusion)
+constexpr bool USE_FLOYD_STEINBERG = false;  // Floyd-Steinberg error diffusion (can cause "worm" artifacts)
+constexpr bool USE_NOISE_DITHERING = false;  // Hash-based noise dithering (good for downsampling)
+// Brightness/Contrast adjustments:
+constexpr bool USE_BRIGHTNESS = true;     // true: apply brightness/gamma adjustments
+constexpr int BRIGHTNESS_BOOST = 10;      // Brightness offset (0-50)
+constexpr bool GAMMA_CORRECTION = true;   // Gamma curve (brightens midtones)
+constexpr float CONTRAST_FACTOR = 1.15f;  // Contrast multiplier (1.0 = no change, >1 = more contrast)
+// Pre-resize to target display size (CRITICAL: avoids dithering artifacts from post-downsampling)
+constexpr bool USE_PRESCALE = true;     // true: scale image to target size before dithering
+constexpr int TARGET_MAX_WIDTH = 480;   // Max width for cover images (portrait display width)
+constexpr int TARGET_MAX_HEIGHT = 800;  // Max height for cover images (portrait display height)
+// ============================================================================
+
+// Integer approximation of gamma correction (brightens midtones)
+// Uses a simple curve: out = 255 * sqrt(in/255) ≈ sqrt(in * 255)
+static inline int applyGamma(int gray) {
+  if (!GAMMA_CORRECTION) return gray;
+  // Fast integer square root approximation for gamma ~0.5 (brightening)
+  // This brightens dark/mid tones while preserving highlights
+  const int product = gray * 255;
+  // Newton-Raphson integer sqrt (2 iterations for good accuracy)
+  int x = gray;
+  if (x > 0) {
+    x = (x + product / x) >> 1;
+    x = (x + product / x) >> 1;
+  }
+  return x > 255 ? 255 : x;
+}
+
+// Apply contrast adjustment around midpoint (128)
+// factor > 1.0 increases contrast, < 1.0 decreases
+static inline int applyContrast(int gray) {
+  // Integer-based contrast: (gray - 128) * factor + 128
+  // Using fixed-point: factor 1.15 ≈ 115/100
+  constexpr int factorNum = static_cast<int>(CONTRAST_FACTOR * 100);
+  int adjusted = ((gray - 128) * factorNum) / 100 + 128;
+  if (adjusted < 0) adjusted = 0;
+  if (adjusted > 255) adjusted = 255;
+  return adjusted;
+}
+
+// Combined brightness/contrast/gamma adjustment
+static inline int adjustPixel(int gray) {
+  if (!USE_BRIGHTNESS) return gray;
+
+  // Order: contrast first, then brightness, then gamma
+  gray = applyContrast(gray);
+  gray += BRIGHTNESS_BOOST;
+  if (gray > 255) gray = 255;
+  if (gray < 0) gray = 0;
+  gray = applyGamma(gray);
+
+  return gray;
+}
+
+// Simple quantization without dithering - just divide into 4 levels
+static inline uint8_t quantizeSimple(int gray) {
+  gray = adjustPixel(gray);
+  // Simple 2-bit quantization: 0-63=0, 64-127=1, 128-191=2, 192-255=3
+  return static_cast<uint8_t>(gray >> 6);
+}
+
+// Hash-based noise dithering - survives downsampling without moiré artifacts
+// Uses integer hash to generate pseudo-random threshold per pixel
+static inline uint8_t quantizeNoise(int gray, int x, int y) {
+  gray = adjustPixel(gray);
+
+  // Generate noise threshold using integer hash (no regular pattern to alias)
+  uint32_t hash = static_cast<uint32_t>(x) * 374761393u + static_cast<uint32_t>(y) * 668265263u;
+  hash = (hash ^ (hash >> 13)) * 1274126177u;
+  const int threshold = static_cast<int>(hash >> 24);  // 0-255
+
+  // Map gray (0-255) to 4 levels with dithering
+  const int scaled = gray * 3;
+
+  if (scaled < 255) {
+    return (scaled + threshold >= 255) ? 1 : 0;
+  } else if (scaled < 510) {
+    return ((scaled - 255) + threshold >= 255) ? 2 : 1;
+  } else {
+    return ((scaled - 510) + threshold >= 255) ? 3 : 2;
+  }
+}
+
+// Main quantization function - selects between methods based on config
+static inline uint8_t quantize(int gray, int x, int y) {
+  if (USE_NOISE_DITHERING) {
+    return quantizeNoise(gray, x, y);
+  } else {
+    return quantizeSimple(gray);
+  }
+}
+
+// Atkinson dithering - distributes only 6/8 (75%) of error for cleaner results
+// Error distribution pattern:
+//     X  1/8 1/8
+// 1/8 1/8 1/8
+//     1/8
+// Less error buildup = fewer artifacts than Floyd-Steinberg
+class AtkinsonDitherer {
+ public:
+  AtkinsonDitherer(int width) : width(width) {
+    errorRow0 = new int16_t[width + 4]();  // Current row
+    errorRow1 = new int16_t[width + 4]();  // Next row
+    errorRow2 = new int16_t[width + 4]();  // Row after next
+  }
+
+  ~AtkinsonDitherer() {
+    delete[] errorRow0;
+    delete[] errorRow1;
+    delete[] errorRow2;
+  }
+
+  uint8_t processPixel(int gray, int x) {
+    // Apply brightness/contrast/gamma adjustments
+    gray = adjustPixel(gray);
+
+    // Add accumulated error
+    int adjusted = gray + errorRow0[x + 2];
+    if (adjusted < 0) adjusted = 0;
+    if (adjusted > 255) adjusted = 255;
+
+    // Quantize to 4 levels
+    uint8_t quantized;
+    int quantizedValue;
+    if (adjusted < 43) {
+      quantized = 0;
+      quantizedValue = 0;
+    } else if (adjusted < 128) {
+      quantized = 1;
+      quantizedValue = 85;
+    } else if (adjusted < 213) {
+      quantized = 2;
+      quantizedValue = 170;
+    } else {
+      quantized = 3;
+      quantizedValue = 255;
+    }
+
+    // Calculate error (only distribute 6/8 = 75%)
+    int error = (adjusted - quantizedValue) >> 3;  // error/8
+
+    // Distribute 1/8 to each of 6 neighbors
+    errorRow0[x + 3] += error;  // Right
+    errorRow0[x + 4] += error;  // Right+1
+    errorRow1[x + 1] += error;  // Bottom-left
+    errorRow1[x + 2] += error;  // Bottom
+    errorRow1[x + 3] += error;  // Bottom-right
+    errorRow2[x + 2] += error;  // Two rows down
+
+    return quantized;
+  }
+
+  void nextRow() {
+    int16_t* temp = errorRow0;
+    errorRow0 = errorRow1;
+    errorRow1 = errorRow2;
+    errorRow2 = temp;
+    memset(errorRow2, 0, (width + 4) * sizeof(int16_t));
+  }
+
+  void reset() {
+    memset(errorRow0, 0, (width + 4) * sizeof(int16_t));
+    memset(errorRow1, 0, (width + 4) * sizeof(int16_t));
+    memset(errorRow2, 0, (width + 4) * sizeof(int16_t));
+  }
+
+ private:
+  int width;
+  int16_t* errorRow0;
+  int16_t* errorRow1;
+  int16_t* errorRow2;
+};
+
+// Floyd-Steinberg error diffusion dithering with serpentine scanning
+// Serpentine scanning alternates direction each row to reduce "worm" artifacts
+// Error distribution pattern (left-to-right):
+//       X   7/16
+// 3/16 5/16 1/16
+// Error distribution pattern (right-to-left, mirrored):
+// 1/16 5/16 3/16
+//      7/16  X
+class FloydSteinbergDitherer {
+ public:
+  FloydSteinbergDitherer(int width) : width(width), rowCount(0) {
+    errorCurRow = new int16_t[width + 2]();  // +2 for boundary handling
+    errorNextRow = new int16_t[width + 2]();
+  }
+
+  ~FloydSteinbergDitherer() {
+    delete[] errorCurRow;
+    delete[] errorNextRow;
+  }
+
+  // Process a single pixel and return quantized 2-bit value
+  // x is the logical x position (0 to width-1), direction handled internally
+  uint8_t processPixel(int gray, int x, bool reverseDirection) {
+    // Add accumulated error to this pixel
+    int adjusted = gray + errorCurRow[x + 1];
+
+    // Clamp to valid range
+    if (adjusted < 0) adjusted = 0;
+    if (adjusted > 255) adjusted = 255;
+
+    // Quantize to 4 levels (0, 85, 170, 255)
+    uint8_t quantized;
+    int quantizedValue;
+    if (adjusted < 43) {
+      quantized = 0;
+      quantizedValue = 0;
+    } else if (adjusted < 128) {
+      quantized = 1;
+      quantizedValue = 85;
+    } else if (adjusted < 213) {
+      quantized = 2;
+      quantizedValue = 170;
+    } else {
+      quantized = 3;
+      quantizedValue = 255;
+    }
+
+    // Calculate error
+    int error = adjusted - quantizedValue;
+
+    // Distribute error to neighbors (serpentine: direction-aware)
+    if (!reverseDirection) {
+      // Left to right: standard distribution
+      // Right: 7/16
+      errorCurRow[x + 2] += (error * 7) >> 4;
+      // Bottom-left: 3/16
+      errorNextRow[x] += (error * 3) >> 4;
+      // Bottom: 5/16
+      errorNextRow[x + 1] += (error * 5) >> 4;
+      // Bottom-right: 1/16
+      errorNextRow[x + 2] += (error) >> 4;
+    } else {
+      // Right to left: mirrored distribution
+      // Left: 7/16
+      errorCurRow[x] += (error * 7) >> 4;
+      // Bottom-right: 3/16
+      errorNextRow[x + 2] += (error * 3) >> 4;
+      // Bottom: 5/16
+      errorNextRow[x + 1] += (error * 5) >> 4;
+      // Bottom-left: 1/16
+      errorNextRow[x] += (error) >> 4;
+    }
+
+    return quantized;
+  }
+
+  // Call at the end of each row to swap buffers
+  void nextRow() {
+    // Swap buffers
+    int16_t* temp = errorCurRow;
+    errorCurRow = errorNextRow;
+    errorNextRow = temp;
+    // Clear the next row buffer
+    memset(errorNextRow, 0, (width + 2) * sizeof(int16_t));
+    rowCount++;
+  }
+
+  // Check if current row should be processed in reverse
+  bool isReverseRow() const { return (rowCount & 1) != 0; }
+
+  // Reset for a new image or MCU block
+  void reset() {
+    memset(errorCurRow, 0, (width + 2) * sizeof(int16_t));
+    memset(errorNextRow, 0, (width + 2) * sizeof(int16_t));
+    rowCount = 0;
+  }
+
+ private:
+  int width;
+  int rowCount;
+  int16_t* errorCurRow;
+  int16_t* errorNextRow;
+};
+
+inline void write16(Print& out, const uint16_t value) {
+  out.write(value & 0xFF);
+  out.write((value >> 8) & 0xFF);
+}
+
+inline void write32(Print& out, const uint32_t value) {
+  out.write(value & 0xFF);
+  out.write((value >> 8) & 0xFF);
+  out.write((value >> 16) & 0xFF);
+  out.write((value >> 24) & 0xFF);
+}
+
+inline void write32Signed(Print& out, const int32_t value) {
+  out.write(value & 0xFF);
+  out.write((value >> 8) & 0xFF);
+  out.write((value >> 16) & 0xFF);
+  out.write((value >> 24) & 0xFF);
+}
+
+// Helper function: Write BMP header with 8-bit grayscale (256 levels)
+void writeBmpHeader8bit(Print& bmpOut, const int width, const int height) {
+  // Calculate row padding (each row must be multiple of 4 bytes)
+  const int bytesPerRow = (width + 3) / 4 * 4;  // 8 bits per pixel, padded
+  const int imageSize = bytesPerRow * height;
+  const uint32_t paletteSize = 256 * 4;  // 256 colors * 4 bytes (BGRA)
+  const uint32_t fileSize = 14 + 40 + paletteSize + imageSize;
+
+  // BMP File Header (14 bytes)
+  bmpOut.write('B');
+  bmpOut.write('M');
+  write32(bmpOut, fileSize);
+  write32(bmpOut, 0);                      // Reserved
+  write32(bmpOut, 14 + 40 + paletteSize);  // Offset to pixel data
+
+  // DIB Header (BITMAPINFOHEADER - 40 bytes)
+  write32(bmpOut, 40);
+  write32Signed(bmpOut, width);
+  write32Signed(bmpOut, -height);  // Negative height = top-down bitmap
+  write16(bmpOut, 1);              // Color planes
+  write16(bmpOut, 8);              // Bits per pixel (8 bits)
+  write32(bmpOut, 0);              // BI_RGB (no compression)
+  write32(bmpOut, imageSize);
+  write32(bmpOut, 2835);  // xPixelsPerMeter (72 DPI)
+  write32(bmpOut, 2835);  // yPixelsPerMeter (72 DPI)
+  write32(bmpOut, 256);   // colorsUsed
+  write32(bmpOut, 256);   // colorsImportant
+
+  // Color Palette (256 grayscale entries x 4 bytes = 1024 bytes)
+  for (int i = 0; i < 256; i++) {
+    bmpOut.write(static_cast<uint8_t>(i));  // Blue
+    bmpOut.write(static_cast<uint8_t>(i));  // Green
+    bmpOut.write(static_cast<uint8_t>(i));  // Red
+    bmpOut.write(static_cast<uint8_t>(0));  // Reserved
+  }
+}
+
+// Helper function: Write BMP header with 2-bit color depth
+void JpegToBmpConverter::writeBmpHeader(Print& bmpOut, const int width, const int height) {
+  // Calculate row padding (each row must be multiple of 4 bytes)
+  const int bytesPerRow = (width * 2 + 31) / 32 * 4;  // 2 bits per pixel, round up
+  const int imageSize = bytesPerRow * height;
+  const uint32_t fileSize = 70 + imageSize;  // 14 (file header) + 40 (DIB header) + 16 (palette) + image
+
+  // BMP File Header (14 bytes)
+  bmpOut.write('B');
+  bmpOut.write('M');
+  write32(bmpOut, fileSize);  // File size
+  write32(bmpOut, 0);         // Reserved
+  write32(bmpOut, 70);        // Offset to pixel data
+
+  // DIB Header (BITMAPINFOHEADER - 40 bytes)
+  write32(bmpOut, 40);
+  write32Signed(bmpOut, width);
+  write32Signed(bmpOut, -height);  // Negative height = top-down bitmap
+  write16(bmpOut, 1);              // Color planes
+  write16(bmpOut, 2);              // Bits per pixel (2 bits)
+  write32(bmpOut, 0);              // BI_RGB (no compression)
+  write32(bmpOut, imageSize);
+  write32(bmpOut, 2835);  // xPixelsPerMeter (72 DPI)
+  write32(bmpOut, 2835);  // yPixelsPerMeter (72 DPI)
+  write32(bmpOut, 4);     // colorsUsed
+  write32(bmpOut, 4);     // colorsImportant
+
+  // Color Palette (4 colors x 4 bytes = 16 bytes)
+  // Format: Blue, Green, Red, Reserved (BGRA)
+  uint8_t palette[16] = {
+      0x00, 0x00, 0x00, 0x00,  // Color 0: Black
+      0x55, 0x55, 0x55, 0x00,  // Color 1: Dark gray (85)
+      0xAA, 0xAA, 0xAA, 0x00,  // Color 2: Light gray (170)
+      0xFF, 0xFF, 0xFF, 0x00   // Color 3: White
+  };
+  for (const uint8_t i : palette) {
+    bmpOut.write(i);
+  }
+}
+
+// Callback function for picojpeg to read JPEG data
+unsigned char JpegToBmpConverter::jpegReadCallback(unsigned char* pBuf, const unsigned char buf_size,
+                                                   unsigned char* pBytes_actually_read, void* pCallback_data) {
+  auto* context = static_cast<JpegReadContext*>(pCallback_data);
+
+  if (!context || !context->file) {
+    return PJPG_STREAM_READ_ERROR;
+  }
+
+  // Check if we need to refill our context buffer
+  if (context->bufferPos >= context->bufferFilled) {
+    context->bufferFilled = context->file.read(context->buffer, sizeof(context->buffer));
+    context->bufferPos = 0;
+
+    if (context->bufferFilled == 0) {
+      // EOF or error
+      *pBytes_actually_read = 0;
+      return 0;  // Success (EOF is normal)
+    }
+  }
+
+  // Copy available bytes to picojpeg's buffer
+  const size_t available = context->bufferFilled - context->bufferPos;
+  const size_t toRead = available < buf_size ? available : buf_size;
+
+  memcpy(pBuf, context->buffer + context->bufferPos, toRead);
+  context->bufferPos += toRead;
+  *pBytes_actually_read = static_cast<unsigned char>(toRead);
+
+  return 0;  // Success
+}
+
+// Core function: Convert JPEG file to 2-bit BMP
+bool JpegToBmpConverter::jpegFileToBmpStream(File& jpegFile, Print& bmpOut) {
+  Serial.printf("[%lu] [JPG] Converting JPEG to BMP\n", millis());
+
+  // Setup context for picojpeg callback
+  JpegReadContext context = {.file = jpegFile, .bufferPos = 0, .bufferFilled = 0};
+
+  // Initialize picojpeg decoder
+  pjpeg_image_info_t imageInfo;
+  const unsigned char status = pjpeg_decode_init(&imageInfo, jpegReadCallback, &context, 0);
+  if (status != 0) {
+    Serial.printf("[%lu] [JPG] JPEG decode init failed with error code: %d\n", millis(), status);
+    return false;
+  }
+
+  Serial.printf("[%lu] [JPG] JPEG dimensions: %dx%d, components: %d, MCUs: %dx%d\n", millis(), imageInfo.m_width,
+                imageInfo.m_height, imageInfo.m_comps, imageInfo.m_MCUSPerRow, imageInfo.m_MCUSPerCol);
+
+  // Safety limits to prevent memory issues on ESP32
+  constexpr int MAX_IMAGE_WIDTH = 2048;
+  constexpr int MAX_IMAGE_HEIGHT = 3072;
+  constexpr int MAX_MCU_ROW_BYTES = 65536;
+
+  if (imageInfo.m_width > MAX_IMAGE_WIDTH || imageInfo.m_height > MAX_IMAGE_HEIGHT) {
+    Serial.printf("[%lu] [JPG] Image too large (%dx%d), max supported: %dx%d\n", millis(), imageInfo.m_width,
+                  imageInfo.m_height, MAX_IMAGE_WIDTH, MAX_IMAGE_HEIGHT);
+    return false;
+  }
+
+  // Calculate output dimensions (pre-scale to fit display exactly)
+  int outWidth = imageInfo.m_width;
+  int outHeight = imageInfo.m_height;
+  // Use fixed-point scaling (16.16) for sub-pixel accuracy
+  uint32_t scaleX_fp = 65536;  // 1.0 in 16.16 fixed point
+  uint32_t scaleY_fp = 65536;
+  bool needsScaling = false;
+
+  if (USE_PRESCALE && (imageInfo.m_width > TARGET_MAX_WIDTH || imageInfo.m_height > TARGET_MAX_HEIGHT)) {
+    // Calculate scale to fit within target dimensions while maintaining aspect ratio
+    const float scaleToFitWidth = static_cast<float>(TARGET_MAX_WIDTH) / imageInfo.m_width;
+    const float scaleToFitHeight = static_cast<float>(TARGET_MAX_HEIGHT) / imageInfo.m_height;
+    const float scale = (scaleToFitWidth < scaleToFitHeight) ? scaleToFitWidth : scaleToFitHeight;
+
+    outWidth = static_cast<int>(imageInfo.m_width * scale);
+    outHeight = static_cast<int>(imageInfo.m_height * scale);
+
+    // Ensure at least 1 pixel
+    if (outWidth < 1) outWidth = 1;
+    if (outHeight < 1) outHeight = 1;
+
+    // Calculate fixed-point scale factors (source pixels per output pixel)
+    // scaleX_fp = (srcWidth << 16) / outWidth
+    scaleX_fp = (static_cast<uint32_t>(imageInfo.m_width) << 16) / outWidth;
+    scaleY_fp = (static_cast<uint32_t>(imageInfo.m_height) << 16) / outHeight;
+    needsScaling = true;
+
+    Serial.printf("[%lu] [JPG] Pre-scaling %dx%d -> %dx%d (fit to %dx%d)\n", millis(), imageInfo.m_width,
+                  imageInfo.m_height, outWidth, outHeight, TARGET_MAX_WIDTH, TARGET_MAX_HEIGHT);
+  }
+
+  // Write BMP header with output dimensions
+  int bytesPerRow;
+  if (USE_8BIT_OUTPUT) {
+    writeBmpHeader8bit(bmpOut, outWidth, outHeight);
+    bytesPerRow = (outWidth + 3) / 4 * 4;
+  } else {
+    writeBmpHeader(bmpOut, outWidth, outHeight);
+    bytesPerRow = (outWidth * 2 + 31) / 32 * 4;
+  }
+
+  // Allocate row buffer
+  auto* rowBuffer = static_cast<uint8_t*>(malloc(bytesPerRow));
+  if (!rowBuffer) {
+    Serial.printf("[%lu] [JPG] Failed to allocate row buffer\n", millis());
+    return false;
+  }
+
+  // Allocate a buffer for one MCU row worth of grayscale pixels
+  // This is the minimal memory needed for streaming conversion
+  const int mcuPixelHeight = imageInfo.m_MCUHeight;
+  const int mcuRowPixels = imageInfo.m_width * mcuPixelHeight;
+
+  // Validate MCU row buffer size before allocation
+  if (mcuRowPixels > MAX_MCU_ROW_BYTES) {
+    Serial.printf("[%lu] [JPG] MCU row buffer too large (%d bytes), max: %d\n", millis(), mcuRowPixels,
+                  MAX_MCU_ROW_BYTES);
+    free(rowBuffer);
+    return false;
+  }
+
+  auto* mcuRowBuffer = static_cast<uint8_t*>(malloc(mcuRowPixels));
+  if (!mcuRowBuffer) {
+    Serial.printf("[%lu] [JPG] Failed to allocate MCU row buffer (%d bytes)\n", millis(), mcuRowPixels);
+    free(rowBuffer);
+    return false;
+  }
+
+  // Create ditherer if enabled (only for 2-bit output)
+  // Use OUTPUT dimensions for dithering (after prescaling)
+  AtkinsonDitherer* atkinsonDitherer = nullptr;
+  FloydSteinbergDitherer* fsDitherer = nullptr;
+  if (!USE_8BIT_OUTPUT) {
+    if (USE_ATKINSON) {
+      atkinsonDitherer = new AtkinsonDitherer(outWidth);
+    } else if (USE_FLOYD_STEINBERG) {
+      fsDitherer = new FloydSteinbergDitherer(outWidth);
+    }
+  }
+
+  // For scaling: accumulate source rows into scaled output rows
+  // We need to track which source Y maps to which output Y
+  // Using fixed-point: srcY_fp = outY * scaleY_fp (gives source Y in 16.16 format)
+  uint32_t* rowAccum = nullptr;    // Accumulator for each output X (32-bit for larger sums)
+  uint16_t* rowCount = nullptr;    // Count of source pixels accumulated per output X
+  int currentOutY = 0;             // Current output row being accumulated
+  uint32_t nextOutY_srcStart = 0;  // Source Y where next output row starts (16.16 fixed point)
+
+  if (needsScaling) {
+    rowAccum = new uint32_t[outWidth]();
+    rowCount = new uint16_t[outWidth]();
+    nextOutY_srcStart = scaleY_fp;  // First boundary is at scaleY_fp (source Y for outY=1)
+  }
+
+  // Process MCUs row-by-row and write to BMP as we go (top-down)
+  const int mcuPixelWidth = imageInfo.m_MCUWidth;
+
+  for (int mcuY = 0; mcuY < imageInfo.m_MCUSPerCol; mcuY++) {
+    // Clear the MCU row buffer
+    memset(mcuRowBuffer, 0, mcuRowPixels);
+
+    // Decode one row of MCUs
+    for (int mcuX = 0; mcuX < imageInfo.m_MCUSPerRow; mcuX++) {
+      const unsigned char mcuStatus = pjpeg_decode_mcu();
+      if (mcuStatus != 0) {
+        if (mcuStatus == PJPG_NO_MORE_BLOCKS) {
+          Serial.printf("[%lu] [JPG] Unexpected end of blocks at MCU (%d, %d)\n", millis(), mcuX, mcuY);
+        } else {
+          Serial.printf("[%lu] [JPG] JPEG decode MCU failed at (%d, %d) with error code: %d\n", millis(), mcuX, mcuY,
+                        mcuStatus);
+        }
+        free(mcuRowBuffer);
+        free(rowBuffer);
+        return false;
+      }
+
+      // picojpeg stores MCU data in 8x8 blocks
+      // Block layout: H2V2(16x16)=0,64,128,192 H2V1(16x8)=0,64 H1V2(8x16)=0,128
+      for (int blockY = 0; blockY < mcuPixelHeight; blockY++) {
+        for (int blockX = 0; blockX < mcuPixelWidth; blockX++) {
+          const int pixelX = mcuX * mcuPixelWidth + blockX;
+          if (pixelX >= imageInfo.m_width) continue;
+
+          // Calculate proper block offset for picojpeg buffer
+          const int blockCol = blockX / 8;
+          const int blockRow = blockY / 8;
+          const int localX = blockX % 8;
+          const int localY = blockY % 8;
+          const int blocksPerRow = mcuPixelWidth / 8;
+          const int blockIndex = blockRow * blocksPerRow + blockCol;
+          const int pixelOffset = blockIndex * 64 + localY * 8 + localX;
+
+          uint8_t gray;
+          if (imageInfo.m_comps == 1) {
+            gray = imageInfo.m_pMCUBufR[pixelOffset];
+          } else {
+            const uint8_t r = imageInfo.m_pMCUBufR[pixelOffset];
+            const uint8_t g = imageInfo.m_pMCUBufG[pixelOffset];
+            const uint8_t b = imageInfo.m_pMCUBufB[pixelOffset];
+            gray = (r * 25 + g * 50 + b * 25) / 100;
+          }
+
+          mcuRowBuffer[blockY * imageInfo.m_width + pixelX] = gray;
+        }
+      }
+    }
+
+    // Process source rows from this MCU row
+    const int startRow = mcuY * mcuPixelHeight;
+    const int endRow = (mcuY + 1) * mcuPixelHeight;
+
+    for (int y = startRow; y < endRow && y < imageInfo.m_height; y++) {
+      const int bufferY = y - startRow;
+
+      if (!needsScaling) {
+        // No scaling - direct output (1:1 mapping)
+        memset(rowBuffer, 0, bytesPerRow);
+
+        if (USE_8BIT_OUTPUT) {
+          for (int x = 0; x < outWidth; x++) {
+            const uint8_t gray = mcuRowBuffer[bufferY * imageInfo.m_width + x];
+            rowBuffer[x] = adjustPixel(gray);
+          }
+        } else {
+          for (int x = 0; x < outWidth; x++) {
+            const uint8_t gray = mcuRowBuffer[bufferY * imageInfo.m_width + x];
+            uint8_t twoBit;
+            if (atkinsonDitherer) {
+              twoBit = atkinsonDitherer->processPixel(gray, x);
+            } else if (fsDitherer) {
+              twoBit = fsDitherer->processPixel(gray, x, fsDitherer->isReverseRow());
+            } else {
+              twoBit = quantize(gray, x, y);
+            }
+            const int byteIndex = (x * 2) / 8;
+            const int bitOffset = 6 - ((x * 2) % 8);
+            rowBuffer[byteIndex] |= (twoBit << bitOffset);
+          }
+          if (atkinsonDitherer)
+            atkinsonDitherer->nextRow();
+          else if (fsDitherer)
+            fsDitherer->nextRow();
+        }
+        bmpOut.write(rowBuffer, bytesPerRow);
+      } else {
+        // Fixed-point area averaging for exact fit scaling
+        // For each output pixel X, accumulate source pixels that map to it
+        // srcX range for outX: [outX * scaleX_fp >> 16, (outX+1) * scaleX_fp >> 16)
+        const uint8_t* srcRow = mcuRowBuffer + bufferY * imageInfo.m_width;
+
+        for (int outX = 0; outX < outWidth; outX++) {
+          // Calculate source X range for this output pixel
+          const int srcXStart = (static_cast<uint32_t>(outX) * scaleX_fp) >> 16;
+          const int srcXEnd = (static_cast<uint32_t>(outX + 1) * scaleX_fp) >> 16;
+
+          // Accumulate all source pixels in this range
+          int sum = 0;
+          int count = 0;
+          for (int srcX = srcXStart; srcX < srcXEnd && srcX < imageInfo.m_width; srcX++) {
+            sum += srcRow[srcX];
+            count++;
+          }
+
+          // Handle edge case: if no pixels in range, use nearest
+          if (count == 0 && srcXStart < imageInfo.m_width) {
+            sum = srcRow[srcXStart];
+            count = 1;
+          }
+
+          rowAccum[outX] += sum;
+          rowCount[outX] += count;
+        }
+
+        // Check if we've crossed into the next output row
+        // Current source Y in fixed point: y << 16
+        const uint32_t srcY_fp = static_cast<uint32_t>(y + 1) << 16;
+
+        // Output row when source Y crosses the boundary
+        if (srcY_fp >= nextOutY_srcStart && currentOutY < outHeight) {
+          memset(rowBuffer, 0, bytesPerRow);
+
+          if (USE_8BIT_OUTPUT) {
+            for (int x = 0; x < outWidth; x++) {
+              const uint8_t gray = (rowCount[x] > 0) ? (rowAccum[x] / rowCount[x]) : 0;
+              rowBuffer[x] = adjustPixel(gray);
+            }
+          } else {
+            for (int x = 0; x < outWidth; x++) {
+              const uint8_t gray = (rowCount[x] > 0) ? (rowAccum[x] / rowCount[x]) : 0;
+              uint8_t twoBit;
+              if (atkinsonDitherer) {
+                twoBit = atkinsonDitherer->processPixel(gray, x);
+              } else if (fsDitherer) {
+                twoBit = fsDitherer->processPixel(gray, x, fsDitherer->isReverseRow());
+              } else {
+                twoBit = quantize(gray, x, currentOutY);
+              }
+              const int byteIndex = (x * 2) / 8;
+              const int bitOffset = 6 - ((x * 2) % 8);
+              rowBuffer[byteIndex] |= (twoBit << bitOffset);
+            }
+            if (atkinsonDitherer)
+              atkinsonDitherer->nextRow();
+            else if (fsDitherer)
+              fsDitherer->nextRow();
+          }
+
+          bmpOut.write(rowBuffer, bytesPerRow);
+          currentOutY++;
+
+          // Reset accumulators for next output row
+          memset(rowAccum, 0, outWidth * sizeof(uint32_t));
+          memset(rowCount, 0, outWidth * sizeof(uint16_t));
+
+          // Update boundary for next output row
+          nextOutY_srcStart = static_cast<uint32_t>(currentOutY + 1) * scaleY_fp;
+        }
+      }
+    }
+  }
+
+  // Clean up
+  if (rowAccum) {
+    delete[] rowAccum;
+  }
+  if (rowCount) {
+    delete[] rowCount;
+  }
+  if (atkinsonDitherer) {
+    delete atkinsonDitherer;
+  }
+  if (fsDitherer) {
+    delete fsDitherer;
+  }
+  free(mcuRowBuffer);
+  free(rowBuffer);
+
+  Serial.printf("[%lu] [JPG] Successfully converted JPEG to BMP\n", millis());
+  return true;
+}

lib/JpegToBmpConverter/JpegToBmpConverter.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include <FS.h>
+
+class ZipFile;
+
+class JpegToBmpConverter {
+  static void writeBmpHeader(Print& bmpOut, int width, int height);
+  // [COMMENTED OUT] static uint8_t grayscaleTo2Bit(uint8_t grayscale, int x, int y);
+  static unsigned char jpegReadCallback(unsigned char* pBuf, unsigned char buf_size,
+                                        unsigned char* pBytes_actually_read, void* pCallback_data);
+
+ public:
+  static bool jpegFileToBmpStream(File& jpegFile, Print& bmpOut);
+};

lib/Serialization/Serialization.h

@@ -1,4 +1,6 @@
 #pragma once
+#include <FS.h>
+
 #include <iostream>
 
 namespace serialization {
@@ -7,21 +9,44 @@ static void writePod(std::ostream& os, const T& value) {
   os.write(reinterpret_cast<const char*>(&value), sizeof(T));
 }
 
+template <typename T>
+static void writePod(File& file, const T& value) {
+  file.write(reinterpret_cast<const uint8_t*>(&value), sizeof(T));
+}
+
 template <typename T>
 static void readPod(std::istream& is, T& value) {
   is.read(reinterpret_cast<char*>(&value), sizeof(T));
 }
 
+template <typename T>
+static void readPod(File& file, T& value) {
+  file.read(reinterpret_cast<uint8_t*>(&value), sizeof(T));
+}
+
 static void writeString(std::ostream& os, const std::string& s) {
   const uint32_t len = s.size();
   writePod(os, len);
   os.write(s.data(), len);
 }
 
+static void writeString(File& file, const std::string& s) {
+  const uint32_t len = s.size();
+  writePod(file, len);
+  file.write(reinterpret_cast<const uint8_t*>(s.data()), len);
+}
+
 static void readString(std::istream& is, std::string& s) {
   uint32_t len;
   readPod(is, len);
   s.resize(len);
   is.read(&s[0], len);
 }
+
+static void readString(File& file, std::string& s) {
+  uint32_t len;
+  readPod(file, len);
+  s.resize(len);
+  file.read(reinterpret_cast<uint8_t*>(&s[0]), len);
+}
 }  // namespace serialization

lib/ZipFile/ZipFile.cpp

@@ -27,31 +27,28 @@ bool inflateOneShot(const uint8_t* inputBuf, const size_t deflatedSize, uint8_t*
   return true;
 }
 
-bool ZipFile::loadFileStat(const char* filename, mz_zip_archive_file_stat* fileStat) const {
+ZipFile::ZipFile(std::string filePath) : filePath(std::move(filePath)) {
-  mz_zip_archive zipArchive = {};
+  const bool status = mz_zip_reader_init_file(&zipArchive, this->filePath.c_str(), 0);
-  const bool status = mz_zip_reader_init_file(&zipArchive, filePath.c_str(), 0);
 
   if (!status) {
-    Serial.printf("[%lu] [ZIP] mz_zip_reader_init_file() failed! Error: %s\n", millis(),
+    Serial.printf("[%lu] [ZIP] mz_zip_reader_init_file() failed for %s! Error: %s\n", millis(), this->filePath.c_str(),
                   mz_zip_get_error_string(zipArchive.m_last_error));
-    return false;
   }
+}
 
+bool ZipFile::loadFileStat(const char* filename, mz_zip_archive_file_stat* fileStat) const {
   // find the file
   mz_uint32 fileIndex = 0;
   if (!mz_zip_reader_locate_file_v2(&zipArchive, filename, nullptr, 0, &fileIndex)) {
     Serial.printf("[%lu] [ZIP] Could not find file %s\n", millis(), filename);
-    mz_zip_reader_end(&zipArchive);
     return false;
   }
 
   if (!mz_zip_reader_file_stat(&zipArchive, fileIndex, fileStat)) {
     Serial.printf("[%lu] [ZIP] mz_zip_reader_file_stat() failed! Error: %s\n", millis(),
                   mz_zip_get_error_string(zipArchive.m_last_error));
-    mz_zip_reader_end(&zipArchive);
     return false;
   }
-  mz_zip_reader_end(&zipArchive);
   return true;
 }
 
@@ -118,6 +115,11 @@ uint8_t* ZipFile::readFileToMemory(const char* filename, size_t* size, const boo
   const auto inflatedDataSize = static_cast<size_t>(fileStat.m_uncomp_size);
   const auto dataSize = trailingNullByte ? inflatedDataSize + 1 : inflatedDataSize;
   const auto data = static_cast<uint8_t*>(malloc(dataSize));
+  if (data == nullptr) {
+    Serial.printf("[%lu] [ZIP] Failed to allocate memory for output buffer (%zu bytes)\n", millis(), dataSize);
+    fclose(file);
+    return nullptr;
+  }
 
   if (fileStat.m_method == MZ_NO_COMPRESSION) {
     // no deflation, just read content

lib/ZipFile/ZipFile.h

@@ -1,19 +1,19 @@
 #pragma once
 #include <Print.h>
 
-#include <functional>
 #include <string>
 
 #include "miniz.h"
 
 class ZipFile {
   std::string filePath;
+  mutable mz_zip_archive zipArchive = {};
   bool loadFileStat(const char* filename, mz_zip_archive_file_stat* fileStat) const;
   long getDataOffset(const mz_zip_archive_file_stat& fileStat) const;
 
  public:
-  explicit ZipFile(std::string filePath) : filePath(std::move(filePath)) {}
+  explicit ZipFile(std::string filePath);
-  ~ZipFile() = default;
+  ~ZipFile() { mz_zip_reader_end(&zipArchive); }
   bool getInflatedFileSize(const char* filename, size_t* size) const;
   uint8_t* readFileToMemory(const char* filename, size_t* size = nullptr, bool trailingNullByte = false) const;
   bool readFileToStream(const char* filename, Print& out, size_t chunkSize) const;

lib/picojpeg/picojpeg.h

@@ -0,0 +1,124 @@
+//------------------------------------------------------------------------------
+// picojpeg - Public domain, Rich Geldreich <richgel99@gmail.com>
+//------------------------------------------------------------------------------
+#ifndef PICOJPEG_H
+#define PICOJPEG_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Error codes
+enum {
+  PJPG_NO_MORE_BLOCKS = 1,
+  PJPG_BAD_DHT_COUNTS,
+  PJPG_BAD_DHT_INDEX,
+  PJPG_BAD_DHT_MARKER,
+  PJPG_BAD_DQT_MARKER,
+  PJPG_BAD_DQT_TABLE,
+  PJPG_BAD_PRECISION,
+  PJPG_BAD_HEIGHT,
+  PJPG_BAD_WIDTH,
+  PJPG_TOO_MANY_COMPONENTS,
+  PJPG_BAD_SOF_LENGTH,
+  PJPG_BAD_VARIABLE_MARKER,
+  PJPG_BAD_DRI_LENGTH,
+  PJPG_BAD_SOS_LENGTH,
+  PJPG_BAD_SOS_COMP_ID,
+  PJPG_W_EXTRA_BYTES_BEFORE_MARKER,
+  PJPG_NO_ARITHMITIC_SUPPORT,
+  PJPG_UNEXPECTED_MARKER,
+  PJPG_NOT_JPEG,
+  PJPG_UNSUPPORTED_MARKER,
+  PJPG_BAD_DQT_LENGTH,
+  PJPG_TOO_MANY_BLOCKS,
+  PJPG_UNDEFINED_QUANT_TABLE,
+  PJPG_UNDEFINED_HUFF_TABLE,
+  PJPG_NOT_SINGLE_SCAN,
+  PJPG_UNSUPPORTED_COLORSPACE,
+  PJPG_UNSUPPORTED_SAMP_FACTORS,
+  PJPG_DECODE_ERROR,
+  PJPG_BAD_RESTART_MARKER,
+  PJPG_ASSERTION_ERROR,
+  PJPG_BAD_SOS_SPECTRAL,
+  PJPG_BAD_SOS_SUCCESSIVE,
+  PJPG_STREAM_READ_ERROR,
+  PJPG_NOTENOUGHMEM,
+  PJPG_UNSUPPORTED_COMP_IDENT,
+  PJPG_UNSUPPORTED_QUANT_TABLE,
+  PJPG_UNSUPPORTED_MODE,  // picojpeg doesn't support progressive JPEG's
+};
+
+// Scan types
+typedef enum { PJPG_GRAYSCALE, PJPG_YH1V1, PJPG_YH2V1, PJPG_YH1V2, PJPG_YH2V2 } pjpeg_scan_type_t;
+
+typedef struct {
+  // Image resolution
+  int m_width;
+  int m_height;
+
+  // Number of components (1 or 3)
+  int m_comps;
+
+  // Total number of minimum coded units (MCU's) per row/col.
+  int m_MCUSPerRow;
+  int m_MCUSPerCol;
+
+  // Scan type
+  pjpeg_scan_type_t m_scanType;
+
+  // MCU width/height in pixels (each is either 8 or 16 depending on the scan type)
+  int m_MCUWidth;
+  int m_MCUHeight;
+
+  // m_pMCUBufR, m_pMCUBufG, and m_pMCUBufB are pointers to internal MCU Y or RGB pixel component buffers.
+  // Each time pjpegDecodeMCU() is called successfully these buffers will be filled with 8x8 pixel blocks of Y or RGB
+  // pixels. Each MCU consists of (m_MCUWidth/8)*(m_MCUHeight/8) Y/RGB blocks: 1 for greyscale/no subsampling, 2 for
+  // H1V2/H2V1, or 4 blocks for H2V2 sampling factors. Each block is a contiguous array of 64 (8x8) bytes of a single
+  // component: either Y for grayscale images, or R, G or B components for color images.
+  //
+  // The 8x8 pixel blocks are organized in these byte arrays like this:
+  //
+  // PJPG_GRAYSCALE: Each MCU is decoded to a single block of 8x8 grayscale pixels.
+  // Only the values in m_pMCUBufR are valid. Each 8 bytes is a row of pixels (raster order: left to right, top to
+  // bottom) from the 8x8 block.
+  //
+  // PJPG_H1V1: Each MCU contains is decoded to a single block of 8x8 RGB pixels.
+  //
+  // PJPG_YH2V1: Each MCU is decoded to 2 blocks, or 16x8 pixels.
+  // The 2 RGB blocks are at byte offsets: 0, 64
+  //
+  // PJPG_YH1V2: Each MCU is decoded to 2 blocks, or 8x16 pixels.
+  // The 2 RGB blocks are at byte offsets: 0,
+  //                                       128
+  //
+  // PJPG_YH2V2: Each MCU is decoded to 4 blocks, or 16x16 pixels.
+  // The 2x2 block array is organized at byte offsets:   0,  64,
+  //                                                   128, 192
+  //
+  // It is up to the caller to copy or blit these pixels from these buffers into the destination bitmap.
+  unsigned char* m_pMCUBufR;
+  unsigned char* m_pMCUBufG;
+  unsigned char* m_pMCUBufB;
+} pjpeg_image_info_t;
+
+typedef unsigned char (*pjpeg_need_bytes_callback_t)(unsigned char* pBuf, unsigned char buf_size,
+                                                     unsigned char* pBytes_actually_read, void* pCallback_data);
+
+// Initializes the decompressor. Returns 0 on success, or one of the above error codes on failure.
+// pNeed_bytes_callback will be called to fill the decompressor's internal input buffer.
+// If reduce is 1, only the first pixel of each block will be decoded. This mode is much faster because it skips the AC
+// dequantization, IDCT and chroma upsampling of every image pixel. Not thread safe.
+unsigned char pjpeg_decode_init(pjpeg_image_info_t* pInfo, pjpeg_need_bytes_callback_t pNeed_bytes_callback,
+                                void* pCallback_data, unsigned char reduce);
+
+// Decompresses the file's next MCU. Returns 0 on success, PJPG_NO_MORE_BLOCKS if no more blocks are available, or an
+// error code. Must be called a total of m_MCUSPerRow*m_MCUSPerCol times to completely decompress the image. Not thread
+// safe.
+unsigned char pjpeg_decode_mcu(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  // PICOJPEG_H

platformio.ini

@@ -1,16 +1,16 @@
 [platformio]
-crosspoint_version = 0.7.0
+crosspoint_version = 0.9.0
 default_envs = default
 
 [base]
-platform = espressif32
+platform = espressif32 @ 6.12.0
 board = esp32-c3-devkitm-1
 framework = arduino
 monitor_speed = 115200
 upload_speed = 921600
 check_tool = cppcheck
+check_flags = --enable=all --suppress=missingIncludeSystem --suppress=unusedFunction --suppress=unmatchedSuppression --suppress=*:*/.pio/* --inline-suppr
 check_skip_packages = yes
-check_severity = medium, high
 
 board_upload.flash_size = 16MB
 board_upload.maximum_size = 16777216
@@ -39,6 +39,8 @@ lib_deps =
   BatteryMonitor=symlink://open-x4-sdk/libs/hardware/BatteryMonitor
   InputManager=symlink://open-x4-sdk/libs/hardware/InputManager
   EInkDisplay=symlink://open-x4-sdk/libs/display/EInkDisplay
+  ArduinoJson @ 7.4.2
+  QRCode @ 0.0.1
 
 [env:default]
 extends = base

src/CrossPointSettings.cpp

@@ -1,32 +1,35 @@
 #include "CrossPointSettings.h"
 
+#include <FsHelpers.h>
 #include <HardwareSerial.h>
 #include <SD.h>
 #include <Serialization.h>
 
-#include <cstdint>
-#include <fstream>
-
 // Initialize the static instance
 CrossPointSettings CrossPointSettings::instance;
 
 namespace {
 constexpr uint8_t SETTINGS_FILE_VERSION = 1;
 // Increment this when adding new persisted settings fields
-constexpr uint8_t SETTINGS_COUNT = 5;
+constexpr uint8_t SETTINGS_COUNT = 6;
-constexpr char SETTINGS_FILE[] = "/sd/.crosspoint/settings.bin";
+constexpr char SETTINGS_FILE[] = "/.crosspoint/settings.bin";
 }  // namespace
 
 bool CrossPointSettings::saveToFile() const {
   // Make sure the directory exists
   SD.mkdir("/.crosspoint");
 
-  std::ofstream outputFile(SETTINGS_FILE);
+  File outputFile;
+  if (!FsHelpers::openFileForWrite("CPS", SETTINGS_FILE, outputFile)) {
+    return false;
+  }
+
   serialization::writePod(outputFile, SETTINGS_FILE_VERSION);
   serialization::writePod(outputFile, SETTINGS_COUNT);
-  serialization::writePod(outputFile, whiteSleepScreen);
+  serialization::writePod(outputFile, sleepScreen);
   serialization::writePod(outputFile, extraParagraphSpacing);
   serialization::writePod(outputFile, shortPwrBtn);
+  serialization::writePod(outputFile, statusBar);
   serialization::writePod(outputFile, landscapeReading);
   serialization::writePod(outputFile, landscapeFlipped);
   outputFile.close();
@@ -36,13 +39,11 @@ bool CrossPointSettings::saveToFile() const {
 }
 
 bool CrossPointSettings::loadFromFile() {
-  if (!SD.exists(SETTINGS_FILE + 3)) {  // +3 to skip "/sd" prefix
+  File inputFile;
-    Serial.printf("[%lu] [CPS] Settings file does not exist, using defaults\n", millis());
+  if (!FsHelpers::openFileForRead("CPS", SETTINGS_FILE, inputFile)) {
     return false;
   }
 
-  std::ifstream inputFile(SETTINGS_FILE);
-
   uint8_t version;
   serialization::readPod(inputFile, version);
   if (version != SETTINGS_FILE_VERSION) {
@@ -57,12 +58,14 @@ bool CrossPointSettings::loadFromFile() {
   // load settings that exist (support older files with fewer fields)
   uint8_t settingsRead = 0;
   do {
-    serialization::readPod(inputFile, whiteSleepScreen);
+    serialization::readPod(inputFile, sleepScreen);
     if (++settingsRead >= fileSettingsCount) break;
     serialization::readPod(inputFile, extraParagraphSpacing);
     if (++settingsRead >= fileSettingsCount) break;
     serialization::readPod(inputFile, shortPwrBtn);
     if (++settingsRead >= fileSettingsCount) break;
+    serialization::readPod(inputFile, statusBar);
+    if (++settingsRead >= fileSettingsCount) break;
     serialization::readPod(inputFile, landscapeReading);
     if (++settingsRead >= fileSettingsCount) break;
     serialization::readPod(inputFile, landscapeFlipped);

src/CrossPointSettings.h

@@ -15,8 +15,16 @@ class CrossPointSettings {
   CrossPointSettings(const CrossPointSettings&) = delete;
   CrossPointSettings& operator=(const CrossPointSettings&) = delete;
 
+  // Should match with SettingsActivity text
+  enum SLEEP_SCREEN_MODE { DARK = 0, LIGHT = 1, CUSTOM = 2, COVER = 3 };
+
+  // Status bar display type enum
+  enum STATUS_BAR_MODE { NONE = 0, NO_PROGRESS = 1, FULL = 2 };
+
   // Sleep screen settings
-  uint8_t whiteSleepScreen = 0;
+  uint8_t sleepScreen = DARK;
+  // Status bar settings
+  uint8_t statusBar = FULL;
   // Text rendering settings
   uint8_t extraParagraphSpacing = 1;
   // Duration of the power button press

src/CrossPointState.cpp

@@ -1,20 +1,22 @@
 #include "CrossPointState.h"
 
+#include <FsHelpers.h>
 #include <HardwareSerial.h>
-#include <SD.h>
 #include <Serialization.h>
 
-#include <fstream>
-
 namespace {
 constexpr uint8_t STATE_FILE_VERSION = 1;
-constexpr char STATE_FILE[] = "/sd/.crosspoint/state.bin";
+constexpr char STATE_FILE[] = "/.crosspoint/state.bin";
 }  // namespace
 
 CrossPointState CrossPointState::instance;
 
 bool CrossPointState::saveToFile() const {
-  std::ofstream outputFile(STATE_FILE);
+  File outputFile;
+  if (!FsHelpers::openFileForWrite("CPS", STATE_FILE, outputFile)) {
+    return false;
+  }
+
   serialization::writePod(outputFile, STATE_FILE_VERSION);
   serialization::writeString(outputFile, openEpubPath);
   outputFile.close();
@@ -22,7 +24,10 @@ bool CrossPointState::saveToFile() const {
 }
 
 bool CrossPointState::loadFromFile() {
-  std::ifstream inputFile(STATE_FILE);
+  File inputFile;
+  if (!FsHelpers::openFileForRead("CPS", STATE_FILE, inputFile)) {
+    return false;
+  }
 
   uint8_t version;
   serialization::readPod(inputFile, version);

src/WifiCredentialStore.cpp

@@ -1,11 +1,10 @@
 #include "WifiCredentialStore.h"
 
+#include <FsHelpers.h>
 #include <HardwareSerial.h>
 #include <SD.h>
 #include <Serialization.h>
 
-#include <fstream>
-
 // Initialize the static instance
 WifiCredentialStore WifiCredentialStore::instance;
 
@@ -14,7 +13,7 @@ namespace {
 constexpr uint8_t WIFI_FILE_VERSION = 1;
 
 // WiFi credentials file path
-constexpr char WIFI_FILE[] = "/sd/.crosspoint/wifi.bin";
+constexpr char WIFI_FILE[] = "/.crosspoint/wifi.bin";
 
 // Obfuscation key - "CrossPoint" in ASCII
 // This is NOT cryptographic security, just prevents casual file reading
@@ -33,9 +32,8 @@ bool WifiCredentialStore::saveToFile() const {
   // Make sure the directory exists
   SD.mkdir("/.crosspoint");
 
-  std::ofstream file(WIFI_FILE, std::ios::binary);
+  File file;
-  if (!file) {
+  if (!FsHelpers::openFileForWrite("WCS", WIFI_FILE, file)) {
-    Serial.printf("[%lu] [WCS] Failed to open wifi.bin for writing\n", millis());
     return false;
   }
 
@@ -62,14 +60,8 @@ bool WifiCredentialStore::saveToFile() const {
 }
 
 bool WifiCredentialStore::loadFromFile() {
-  if (!SD.exists(WIFI_FILE + 3)) {  // +3 to skip "/sd" prefix
+  File file;
-    Serial.printf("[%lu] [WCS] WiFi credentials file does not exist\n", millis());
+  if (!FsHelpers::openFileForRead("WCS", WIFI_FILE, file)) {
-    return false;
-  }
-
-  std::ifstream file(WIFI_FILE, std::ios::binary);
-  if (!file) {
-    Serial.printf("[%lu] [WCS] Failed to open wifi.bin for reading\n", millis());
     return false;
   }
 
@@ -111,13 +103,13 @@ bool WifiCredentialStore::loadFromFile() {
 
 bool WifiCredentialStore::addCredential(const std::string& ssid, const std::string& password) {
   // Check if this SSID already exists and update it
-  for (auto& cred : credentials) {
+  const auto cred = find_if(credentials.begin(), credentials.end(),
-    if (cred.ssid == ssid) {
+                            [&ssid](const WifiCredential& cred) { return cred.ssid == ssid; });
-      cred.password = password;
+  if (cred != credentials.end()) {
+    cred->password = password;
     Serial.printf("[%lu] [WCS] Updated credentials for: %s\n", millis(), ssid.c_str());
     return saveToFile();
   }
-  }
 
   // Check if we've reached the limit
   if (credentials.size() >= MAX_NETWORKS) {
@@ -132,22 +124,24 @@ bool WifiCredentialStore::addCredential(const std::string& ssid, const std::stri
 }
 
 bool WifiCredentialStore::removeCredential(const std::string& ssid) {
-  for (auto it = credentials.begin(); it != credentials.end(); ++it) {
+  const auto cred = find_if(credentials.begin(), credentials.end(),
-    if (it->ssid == ssid) {
+                            [&ssid](const WifiCredential& cred) { return cred.ssid == ssid; });
-      credentials.erase(it);
+  if (cred != credentials.end()) {
+    credentials.erase(cred);
     Serial.printf("[%lu] [WCS] Removed credentials for: %s\n", millis(), ssid.c_str());
     return saveToFile();
   }
-  }
   return false;  // Not found
 }
 
 const WifiCredential* WifiCredentialStore::findCredential(const std::string& ssid) const {
-  for (const auto& cred : credentials) {
+  const auto cred = find_if(credentials.begin(), credentials.end(),
-    if (cred.ssid == ssid) {
+                            [&ssid](const WifiCredential& cred) { return cred.ssid == ssid; });
-      return &cred;
+
-    }
+  if (cred != credentials.end()) {
+    return &*cred;
   }
+
   return nullptr;
 }
 

src/activities/Activity.h

@@ -1,19 +1,25 @@
 #pragma once
-#include <InputManager.h>
 
+#include <HardwareSerial.h>
+
+#include <string>
+#include <utility>
+
+class InputManager;
 class GfxRenderer;
 
 class Activity {
  protected:
+  std::string name;
   GfxRenderer& renderer;
   InputManager& inputManager;
 
  public:
-  explicit Activity(GfxRenderer& renderer, InputManager& inputManager)
+  explicit Activity(std::string name, GfxRenderer& renderer, InputManager& inputManager)
-      : renderer(renderer), inputManager(inputManager) {}
+      : name(std::move(name)), renderer(renderer), inputManager(inputManager) {}
   virtual ~Activity() = default;
-  virtual void onEnter() {}
+  virtual void onEnter() { Serial.printf("[%lu] [ACT] Entering activity: %s\n", millis(), name.c_str()); }
-  virtual void onExit() {}
+  virtual void onExit() { Serial.printf("[%lu] [ACT] Exiting activity: %s\n", millis(), name.c_str()); }
   virtual void loop() {}
   virtual bool skipLoopDelay() { return false; }
 };

src/activities/ActivityWithSubactivity.cpp

@@ -18,4 +18,7 @@ void ActivityWithSubactivity::loop() {
   }
 }
 
-void ActivityWithSubactivity::onExit() { exitActivity(); }
+void ActivityWithSubactivity::onExit() {
+  Activity::onExit();
+  exitActivity();
+}

src/activities/ActivityWithSubactivity.h

@@ -10,8 +10,8 @@ class ActivityWithSubactivity : public Activity {
   void enterNewActivity(Activity* activity);
 
  public:
-  explicit ActivityWithSubactivity(GfxRenderer& renderer, InputManager& inputManager)
+  explicit ActivityWithSubactivity(std::string name, GfxRenderer& renderer, InputManager& inputManager)
-      : Activity(renderer, inputManager) {}
+      : Activity(std::move(name), renderer, inputManager) {}
   void loop() override;
   void onExit() override;
 };

src/activities/boot_sleep/BootActivity.cpp

@@ -6,6 +6,8 @@
 #include "images/CrossLarge.h"
 
 void BootActivity::onEnter() {
+  Activity::onEnter();
+
   const auto pageWidth = GfxRenderer::getScreenWidth();
   const auto pageHeight = GfxRenderer::getScreenHeight();
 

src/activities/boot_sleep/BootActivity.h

@@ -3,6 +3,6 @@
 
 class BootActivity final : public Activity {
  public:
-  explicit BootActivity(GfxRenderer& renderer, InputManager& inputManager) : Activity(renderer, inputManager) {}
+  explicit BootActivity(GfxRenderer& renderer, InputManager& inputManager) : Activity("Boot", renderer, inputManager) {}
   void onEnter() override;
 };

src/activities/boot_sleep/SleepActivity.cpp

@@ -1,16 +1,47 @@
 #include "SleepActivity.h"
 
+#include <Epub.h>
+#include <FsHelpers.h>
 #include <GfxRenderer.h>
+#include <SD.h>
 
 #include <vector>
 
 #include "CrossPointSettings.h"
-#include "SD.h"
+#include "CrossPointState.h"
 #include "config.h"
 #include "images/CrossLarge.h"
 
 void SleepActivity::onEnter() {
+  Activity::onEnter();
   renderPopup("Entering Sleep...");
+
+  if (SETTINGS.sleepScreen == CrossPointSettings::SLEEP_SCREEN_MODE::CUSTOM) {
+    return renderCustomSleepScreen();
+  }
+
+  if (SETTINGS.sleepScreen == CrossPointSettings::SLEEP_SCREEN_MODE::COVER) {
+    return renderCoverSleepScreen();
+  }
+
+  renderDefaultSleepScreen();
+}
+
+void SleepActivity::renderPopup(const char* message) const {
+  const int textWidth = renderer.getTextWidth(READER_FONT_ID, message);
+  constexpr int margin = 20;
+  const int x = (renderer.getScreenWidth() - textWidth - margin * 2) / 2;
+  constexpr int y = 117;
+  const int w = textWidth + margin * 2;
+  const int h = renderer.getLineHeight(READER_FONT_ID) + margin * 2;
+  // renderer.clearScreen();
+  renderer.fillRect(x + 5, y + 5, w - 10, h - 10, false);
+  renderer.drawText(READER_FONT_ID, x + margin, y + margin, message);
+  renderer.drawRect(x + 5, y + 5, w - 10, h - 10);
+  renderer.displayBuffer();
+}
+
+void SleepActivity::renderCustomSleepScreen() const {
   // Check if we have a /sleep directory
   auto dir = SD.open("/sleep");
   if (dir && dir.isDirectory()) {
@@ -28,31 +59,31 @@ void SleepActivity::onEnter() {
       }
 
       if (filename.substr(filename.length() - 4) != ".bmp") {
-        Serial.printf("[%lu] [Slp] Skipping non-.bmp file name: %s\n", millis(), file.name());
+        Serial.printf("[%lu] [SLP] Skipping non-.bmp file name: %s\n", millis(), file.name());
         file.close();
         continue;
       }
       Bitmap bitmap(file);
       if (bitmap.parseHeaders() != BmpReaderError::Ok) {
-        Serial.printf("[%lu] [Slp] Skipping invalid BMP file: %s\n", millis(), file.name());
+        Serial.printf("[%lu] [SLP] Skipping invalid BMP file: %s\n", millis(), file.name());
         file.close();
         continue;
       }
       files.emplace_back(filename);
       file.close();
     }
-    int numFiles = files.size();
+    const auto numFiles = files.size();
     if (numFiles > 0) {
       // Generate a random number between 1 and numFiles
-      int randomFileIndex = random(numFiles);
+      const auto randomFileIndex = random(numFiles);
-      auto filename = "/sleep/" + files[randomFileIndex];
+      const auto filename = "/sleep/" + files[randomFileIndex];
-      auto file = SD.open(filename.c_str());
+      File file;
-      if (file) {
+      if (FsHelpers::openFileForRead("SLP", filename, file)) {
-        Serial.printf("[%lu] [Slp] Randomly loading: /sleep/%s\n", millis(), files[randomFileIndex].c_str());
+        Serial.printf("[%lu] [SLP] Randomly loading: /sleep/%s\n", millis(), files[randomFileIndex].c_str());
         delay(100);
         Bitmap bitmap(file);
         if (bitmap.parseHeaders() == BmpReaderError::Ok) {
-          renderCustomSleepScreen(bitmap);
+          renderBitmapSleepScreen(bitmap);
           dir.close();
           return;
         }
@@ -63,12 +94,12 @@ void SleepActivity::onEnter() {
 
   // Look for sleep.bmp on the root of the sd card to determine if we should
   // render a custom sleep screen instead of the default.
-  auto file = SD.open("/sleep.bmp");
+  File file;
-  if (file) {
+  if (FsHelpers::openFileForRead("SLP", "/sleep.bmp", file)) {
     Bitmap bitmap(file);
     if (bitmap.parseHeaders() == BmpReaderError::Ok) {
-      Serial.printf("[%lu] [Slp] Loading: /sleep.bmp\n", millis());
+      Serial.printf("[%lu] [SLP] Loading: /sleep.bmp\n", millis());
-      renderCustomSleepScreen(bitmap);
+      renderBitmapSleepScreen(bitmap);
       return;
     }
   }
@@ -76,41 +107,27 @@ void SleepActivity::onEnter() {
   renderDefaultSleepScreen();
 }
 
-void SleepActivity::renderPopup(const char* message) const {
-  const int textWidth = renderer.getTextWidth(READER_FONT_ID, message);
-  constexpr int margin = 20;
-  const int x = (GfxRenderer::getScreenWidth() - textWidth - margin * 2) / 2;
-  constexpr int y = 117;
-  const int w = textWidth + margin * 2;
-  const int h = renderer.getLineHeight(READER_FONT_ID) + margin * 2;
-  // renderer.clearScreen();
-  renderer.fillRect(x + 5, y + 5, w - 10, h - 10, false);
-  renderer.drawText(READER_FONT_ID, x + margin, y + margin, message);
-  renderer.drawRect(x + 5, y + 5, w - 10, h - 10);
-  renderer.displayBuffer();
-}
-
 void SleepActivity::renderDefaultSleepScreen() const {
-  const auto pageWidth = GfxRenderer::getScreenWidth();
+  const auto pageWidth = renderer.getScreenWidth();
-  const auto pageHeight = GfxRenderer::getScreenHeight();
+  const auto pageHeight = renderer.getScreenHeight();
 
   renderer.clearScreen();
   renderer.drawImage(CrossLarge, (pageWidth - 128) / 2, (pageHeight - 128) / 2, 128, 128);
   renderer.drawCenteredText(UI_FONT_ID, pageHeight / 2 + 70, "CrossPoint", true, BOLD);
   renderer.drawCenteredText(SMALL_FONT_ID, pageHeight / 2 + 95, "SLEEPING");
 
-  // Apply white screen if enabled in settings
+  // Make sleep screen dark unless light is selected in settings
-  if (!SETTINGS.whiteSleepScreen) {
+  if (SETTINGS.sleepScreen != CrossPointSettings::SLEEP_SCREEN_MODE::LIGHT) {
     renderer.invertScreen();
   }
 
   renderer.displayBuffer(EInkDisplay::HALF_REFRESH);
 }
 
-void SleepActivity::renderCustomSleepScreen(const Bitmap& bitmap) const {
+void SleepActivity::renderBitmapSleepScreen(const Bitmap& bitmap) const {
   int x, y;
-  const auto pageWidth = GfxRenderer::getScreenWidth();
+  const auto pageWidth = renderer.getScreenWidth();
-  const auto pageHeight = GfxRenderer::getScreenHeight();
+  const auto pageHeight = renderer.getScreenHeight();
 
   if (bitmap.getWidth() > pageWidth || bitmap.getHeight() > pageHeight) {
     // image will scale, make sure placement is right
@@ -153,3 +170,31 @@ void SleepActivity::renderCustomSleepScreen(const Bitmap& bitmap) const {
     renderer.setRenderMode(GfxRenderer::BW);
   }
 }
+
+void SleepActivity::renderCoverSleepScreen() const {
+  if (APP_STATE.openEpubPath.empty()) {
+    return renderDefaultSleepScreen();
+  }
+
+  Epub lastEpub(APP_STATE.openEpubPath, "/.crosspoint");
+  if (!lastEpub.load()) {
+    Serial.println("[SLP] Failed to load last epub");
+    return renderDefaultSleepScreen();
+  }
+
+  if (!lastEpub.generateCoverBmp()) {
+    Serial.println("[SLP] Failed to generate cover bmp");
+    return renderDefaultSleepScreen();
+  }
+
+  File file;
+  if (FsHelpers::openFileForRead("SLP", lastEpub.getCoverBmpPath(), file)) {
+    Bitmap bitmap(file);
+    if (bitmap.parseHeaders() == BmpReaderError::Ok) {
+      renderBitmapSleepScreen(bitmap);
+      return;
+    }
+  }
+
+  renderDefaultSleepScreen();
+}

src/activities/boot_sleep/SleepActivity.h

@@ -5,11 +5,14 @@ class Bitmap;
 
 class SleepActivity final : public Activity {
  public:
-  explicit SleepActivity(GfxRenderer& renderer, InputManager& inputManager) : Activity(renderer, inputManager) {}
+  explicit SleepActivity(GfxRenderer& renderer, InputManager& inputManager)
+      : Activity("Sleep", renderer, inputManager) {}
   void onEnter() override;
 
  private:
-  void renderDefaultSleepScreen() const;
-  void renderCustomSleepScreen(const Bitmap& bitmap) const;
   void renderPopup(const char* message) const;
+  void renderDefaultSleepScreen() const;
+  void renderCustomSleepScreen() const;
+  void renderCoverSleepScreen() const;
+  void renderBitmapSleepScreen(const Bitmap& bitmap) const;
 };

src/activities/home/HomeActivity.cpp

@@ -1,22 +1,27 @@
 #include "HomeActivity.h"
 
 #include <GfxRenderer.h>
+#include <InputManager.h>
 #include <SD.h>
 
+#include "CrossPointState.h"
 #include "config.h"
 
-namespace {
-constexpr int menuItemCount = 3;
-}
-
 void HomeActivity::taskTrampoline(void* param) {
   auto* self = static_cast<HomeActivity*>(param);
   self->displayTaskLoop();
 }
 
+int HomeActivity::getMenuItemCount() const { return hasContinueReading ? 4 : 3; }
+
 void HomeActivity::onEnter() {
+  Activity::onEnter();
+
   renderingMutex = xSemaphoreCreateMutex();
 
+  // Check if we have a book to continue reading
+  hasContinueReading = !APP_STATE.openEpubPath.empty() && SD.exists(APP_STATE.openEpubPath.c_str());
+
   selectorIndex = 0;
 
   // Trigger first update
@@ -31,6 +36,8 @@ void HomeActivity::onEnter() {
 }
 
 void HomeActivity::onExit() {
+  Activity::onExit();
+
   // Wait until not rendering to delete task to avoid killing mid-instruction to EPD
   xSemaphoreTake(renderingMutex, portMAX_DELAY);
   if (displayTaskHandle) {
@@ -47,7 +54,22 @@ void HomeActivity::loop() {
   const bool nextPressed =
       inputManager.wasPressed(InputManager::BTN_DOWN) || inputManager.wasPressed(InputManager::BTN_RIGHT);
 
+  const int menuCount = getMenuItemCount();
+
   if (inputManager.wasPressed(InputManager::BTN_CONFIRM)) {
+    if (hasContinueReading) {
+      // Menu: Continue Reading, Browse, File transfer, Settings
+      if (selectorIndex == 0) {
+        onContinueReading();
+      } else if (selectorIndex == 1) {
+        onReaderOpen();
+      } else if (selectorIndex == 2) {
+        onFileTransferOpen();
+      } else if (selectorIndex == 3) {
+        onSettingsOpen();
+      }
+    } else {
+      // Menu: Browse, File transfer, Settings
       if (selectorIndex == 0) {
         onReaderOpen();
       } else if (selectorIndex == 1) {
@@ -55,11 +77,12 @@ void HomeActivity::loop() {
       } else if (selectorIndex == 2) {
         onSettingsOpen();
       }
+    }
   } else if (prevPressed) {
-    selectorIndex = (selectorIndex + menuItemCount - 1) % menuItemCount;
+    selectorIndex = (selectorIndex + menuCount - 1) % menuCount;
     updateRequired = true;
   } else if (nextPressed) {
-    selectorIndex = (selectorIndex + 1) % menuItemCount;
+    selectorIndex = (selectorIndex + 1) % menuCount;
     updateRequired = true;
   }
 }
@@ -79,28 +102,48 @@ void HomeActivity::displayTaskLoop() {
 void HomeActivity::render() const {
   renderer.clearScreen();
 
-  const auto pageWidth = GfxRenderer::getScreenWidth();
+  const auto pageWidth = renderer.getScreenWidth();
-  const auto pageHeight = GfxRenderer::getScreenHeight();
   renderer.drawCenteredText(READER_FONT_ID, 10, "CrossPoint Reader", true, BOLD);
 
   // Draw selection
   renderer.fillRect(0, 60 + selectorIndex * 30 + 2, pageWidth - 1, 30);
-  renderer.drawText(UI_FONT_ID, 20, 60, "Read", selectorIndex != 0);
-  renderer.drawText(UI_FONT_ID, 20, 90, "File transfer", selectorIndex != 1);
-  renderer.drawText(UI_FONT_ID, 20, 120, "Settings", selectorIndex != 2);
 
-  renderer.drawRect(25, pageHeight - 40, 106, 40);
+  int menuY = 60;
-  renderer.drawText(UI_FONT_ID, 25 + (105 - renderer.getTextWidth(UI_FONT_ID, "Back")) / 2, pageHeight - 35, "Back");
+  int menuIndex = 0;
 
-  renderer.drawRect(130, pageHeight - 40, 106, 40);
+  if (hasContinueReading) {
-  renderer.drawText(UI_FONT_ID, 130 + (105 - renderer.getTextWidth(UI_FONT_ID, "Confirm")) / 2, pageHeight - 35,
+    // Extract filename from path for display
-                    "Confirm");
+    std::string bookName = APP_STATE.openEpubPath;
+    const size_t lastSlash = bookName.find_last_of('/');
+    if (lastSlash != std::string::npos) {
+      bookName = bookName.substr(lastSlash + 1);
+    }
+    // Remove .epub extension
+    if (bookName.length() > 5 && bookName.substr(bookName.length() - 5) == ".epub") {
+      bookName.resize(bookName.length() - 5);
+    }
+    // Truncate if too long
+    if (bookName.length() > 25) {
+      bookName.resize(22);
+      bookName += "...";
+    }
+    std::string continueLabel = "Continue: " + bookName;
+    renderer.drawText(UI_FONT_ID, 20, menuY, continueLabel.c_str(), selectorIndex != menuIndex);
+    menuY += 30;
+    menuIndex++;
+  }
 
-  renderer.drawRect(245, pageHeight - 40, 106, 40);
+  renderer.drawText(UI_FONT_ID, 20, menuY, "Browse", selectorIndex != menuIndex);
-  renderer.drawText(UI_FONT_ID, 245 + (105 - renderer.getTextWidth(UI_FONT_ID, "Left")) / 2, pageHeight - 35, "Left");
+  menuY += 30;
+  menuIndex++;
 
-  renderer.drawRect(350, pageHeight - 40, 106, 40);
+  renderer.drawText(UI_FONT_ID, 20, menuY, "File transfer", selectorIndex != menuIndex);
-  renderer.drawText(UI_FONT_ID, 350 + (105 - renderer.getTextWidth(UI_FONT_ID, "Right")) / 2, pageHeight - 35, "Right");
+  menuY += 30;
+  menuIndex++;
+
+  renderer.drawText(UI_FONT_ID, 20, menuY, "Settings", selectorIndex != menuIndex);
+
+  renderer.drawButtonHints(UI_FONT_ID, "Back", "Confirm", "Left", "Right");
 
   renderer.displayBuffer();
 }

src/activities/home/HomeActivity.h

@@ -12,6 +12,8 @@ class HomeActivity final : public Activity {
   SemaphoreHandle_t renderingMutex = nullptr;
   int selectorIndex = 0;
   bool updateRequired = false;
+  bool hasContinueReading = false;
+  const std::function<void()> onContinueReading;
   const std::function<void()> onReaderOpen;
   const std::function<void()> onSettingsOpen;
   const std::function<void()> onFileTransferOpen;
@@ -19,11 +21,14 @@ class HomeActivity final : public Activity {
   static void taskTrampoline(void* param);
   [[noreturn]] void displayTaskLoop();
   void render() const;
+  int getMenuItemCount() const;
 
  public:
-  explicit HomeActivity(GfxRenderer& renderer, InputManager& inputManager, const std::function<void()>& onReaderOpen,
+  explicit HomeActivity(GfxRenderer& renderer, InputManager& inputManager,
+                        const std::function<void()>& onContinueReading, const std::function<void()>& onReaderOpen,
                         const std::function<void()>& onSettingsOpen, const std::function<void()>& onFileTransferOpen)
-      : Activity(renderer, inputManager),
+      : Activity("Home", renderer, inputManager),
+        onContinueReading(onContinueReading),
         onReaderOpen(onReaderOpen),
         onSettingsOpen(onSettingsOpen),
         onFileTransferOpen(onFileTransferOpen) {}

src/activities/network/CrossPointWebServerActivity.cpp

@@ -1,23 +1,47 @@
 #include "CrossPointWebServerActivity.h"
 
+#include <DNSServer.h>
+#include <ESPmDNS.h>
 #include <GfxRenderer.h>
+#include <InputManager.h>
 #include <WiFi.h>
+#include <qrcode.h>
 
+#include <cstddef>
+
+#include "NetworkModeSelectionActivity.h"
+#include "WifiSelectionActivity.h"
 #include "config.h"
 
+namespace {
+// AP Mode configuration
+constexpr const char* AP_SSID = "CrossPoint-Reader";
+constexpr const char* AP_PASSWORD = nullptr;  // Open network for ease of use
+constexpr const char* AP_HOSTNAME = "crosspoint";
+constexpr uint8_t AP_CHANNEL = 1;
+constexpr uint8_t AP_MAX_CONNECTIONS = 4;
+
+// DNS server for captive portal (redirects all DNS queries to our IP)
+DNSServer* dnsServer = nullptr;
+constexpr uint16_t DNS_PORT = 53;
+}  // namespace
+
 void CrossPointWebServerActivity::taskTrampoline(void* param) {
   auto* self = static_cast<CrossPointWebServerActivity*>(param);
   self->displayTaskLoop();
 }
 
 void CrossPointWebServerActivity::onEnter() {
-  Serial.printf("[%lu] [WEBACT] ========== CrossPointWebServerActivity onEnter ==========\n", millis());
+  ActivityWithSubactivity::onEnter();
+
   Serial.printf("[%lu] [WEBACT] [MEM] Free heap at onEnter: %d bytes\n", millis(), ESP.getFreeHeap());
 
   renderingMutex = xSemaphoreCreateMutex();
 
   // Reset state
-  state = WebServerActivityState::WIFI_SELECTION;
+  state = WebServerActivityState::MODE_SELECTION;
+  networkMode = NetworkMode::JOIN_NETWORK;
+  isApMode = false;
   connectedIP.clear();
   connectedSSID.clear();
   lastHandleClientTime = 0;
@@ -30,19 +54,17 @@ void CrossPointWebServerActivity::onEnter() {
               &displayTaskHandle  // Task handle
   );
 
-  // Turn on WiFi immediately
+  // Launch network mode selection subactivity
-  Serial.printf("[%lu] [WEBACT] Turning on WiFi...\n", millis());
+  Serial.printf("[%lu] [WEBACT] Launching NetworkModeSelectionActivity...\n", millis());
-  WiFi.mode(WIFI_STA);
+  enterNewActivity(new NetworkModeSelectionActivity(
-
+      renderer, inputManager, [this](const NetworkMode mode) { onNetworkModeSelected(mode); },
-  // Launch WiFi selection subactivity
+      [this]() { onGoBack(); }  // Cancel goes back to home
-  Serial.printf("[%lu] [WEBACT] Launching WifiSelectionActivity...\n", millis());
+      ));
-  wifiSelection.reset(new WifiSelectionActivity(renderer, inputManager,
-                                                [this](bool connected) { onWifiSelectionComplete(connected); }));
-  wifiSelection->onEnter();
 }
 
 void CrossPointWebServerActivity::onExit() {
-  Serial.printf("[%lu] [WEBACT] ========== CrossPointWebServerActivity onExit START ==========\n", millis());
+  ActivityWithSubactivity::onExit();
+
   Serial.printf("[%lu] [WEBACT] [MEM] Free heap at onExit start: %d bytes\n", millis(), ESP.getFreeHeap());
 
   state = WebServerActivityState::SHUTTING_DOWN;
@@ -50,12 +72,15 @@ void CrossPointWebServerActivity::onExit() {
   // Stop the web server first (before disconnecting WiFi)
   stopWebServer();
 
-  // Exit WiFi selection subactivity if still active
+  // Stop mDNS
-  if (wifiSelection) {
+  MDNS.end();
-    Serial.printf("[%lu] [WEBACT] Exiting WifiSelectionActivity...\n", millis());
+
-    wifiSelection->onExit();
+  // Stop DNS server if running (AP mode)
-    wifiSelection.reset();
+  if (dnsServer) {
-    Serial.printf("[%lu] [WEBACT] WifiSelectionActivity exited\n", millis());
+    Serial.printf("[%lu] [WEBACT] Stopping DNS server...\n", millis());
+    dnsServer->stop();
+    delete dnsServer;
+    dnsServer = nullptr;
   }
 
   // CRITICAL: Wait for LWIP stack to flush any pending packets
@@ -63,8 +88,13 @@ void CrossPointWebServerActivity::onExit() {
   delay(500);
 
   // Disconnect WiFi gracefully
+  if (isApMode) {
+    Serial.printf("[%lu] [WEBACT] Stopping WiFi AP...\n", millis());
+    WiFi.softAPdisconnect(true);
+  } else {
     Serial.printf("[%lu] [WEBACT] Disconnecting WiFi (graceful)...\n", millis());
     WiFi.disconnect(false);  // false = don't erase credentials, send disconnect frame
+  }
   delay(100);  // Allow disconnect frame to be sent
 
   Serial.printf("[%lu] [WEBACT] Setting WiFi mode OFF...\n", millis());
@@ -92,29 +122,119 @@ void CrossPointWebServerActivity::onExit() {
   Serial.printf("[%lu] [WEBACT] Mutex deleted\n", millis());
 
   Serial.printf("[%lu] [WEBACT] [MEM] Free heap at onExit end: %d bytes\n", millis(), ESP.getFreeHeap());
-  Serial.printf("[%lu] [WEBACT] ========== CrossPointWebServerActivity onExit COMPLETE ==========\n", millis());
 }
 
-void CrossPointWebServerActivity::onWifiSelectionComplete(bool connected) {
+void CrossPointWebServerActivity::onNetworkModeSelected(const NetworkMode mode) {
+  Serial.printf("[%lu] [WEBACT] Network mode selected: %s\n", millis(),
+                mode == NetworkMode::JOIN_NETWORK ? "Join Network" : "Create Hotspot");
+
+  networkMode = mode;
+  isApMode = (mode == NetworkMode::CREATE_HOTSPOT);
+
+  // Exit mode selection subactivity
+  exitActivity();
+
+  if (mode == NetworkMode::JOIN_NETWORK) {
+    // STA mode - launch WiFi selection
+    Serial.printf("[%lu] [WEBACT] Turning on WiFi (STA mode)...\n", millis());
+    WiFi.mode(WIFI_STA);
+
+    state = WebServerActivityState::WIFI_SELECTION;
+    Serial.printf("[%lu] [WEBACT] Launching WifiSelectionActivity...\n", millis());
+    enterNewActivity(new WifiSelectionActivity(renderer, inputManager,
+                                               [this](const bool connected) { onWifiSelectionComplete(connected); }));
+  } else {
+    // AP mode - start access point
+    state = WebServerActivityState::AP_STARTING;
+    updateRequired = true;
+    startAccessPoint();
+  }
+}
+
+void CrossPointWebServerActivity::onWifiSelectionComplete(const bool connected) {
   Serial.printf("[%lu] [WEBACT] WifiSelectionActivity completed, connected=%d\n", millis(), connected);
 
   if (connected) {
     // Get connection info before exiting subactivity
-    connectedIP = wifiSelection->getConnectedIP();
+    connectedIP = static_cast<WifiSelectionActivity*>(subActivity.get())->getConnectedIP();
     connectedSSID = WiFi.SSID().c_str();
+    isApMode = false;
 
-    // Exit the wifi selection subactivity
+    exitActivity();
-    wifiSelection->onExit();
+
-    wifiSelection.reset();
+    // Start mDNS for hostname resolution
+    if (MDNS.begin(AP_HOSTNAME)) {
+      Serial.printf("[%lu] [WEBACT] mDNS started: http://%s.local/\n", millis(), AP_HOSTNAME);
+    }
 
     // Start the web server
     startWebServer();
   } else {
-    // User cancelled - go back
+    // User cancelled - go back to mode selection
-    onGoBack();
+    exitActivity();
+    state = WebServerActivityState::MODE_SELECTION;
+    enterNewActivity(new NetworkModeSelectionActivity(
+        renderer, inputManager, [this](const NetworkMode mode) { onNetworkModeSelected(mode); },
+        [this]() { onGoBack(); }));
   }
 }
 
+void CrossPointWebServerActivity::startAccessPoint() {
+  Serial.printf("[%lu] [WEBACT] Starting Access Point mode...\n", millis());
+  Serial.printf("[%lu] [WEBACT] [MEM] Free heap before AP start: %d bytes\n", millis(), ESP.getFreeHeap());
+
+  // Configure and start the AP
+  WiFi.mode(WIFI_AP);
+  delay(100);
+
+  // Start soft AP
+  bool apStarted;
+  if (AP_PASSWORD && strlen(AP_PASSWORD) >= 8) {
+    apStarted = WiFi.softAP(AP_SSID, AP_PASSWORD, AP_CHANNEL, false, AP_MAX_CONNECTIONS);
+  } else {
+    // Open network (no password)
+    apStarted = WiFi.softAP(AP_SSID, nullptr, AP_CHANNEL, false, AP_MAX_CONNECTIONS);
+  }
+
+  if (!apStarted) {
+    Serial.printf("[%lu] [WEBACT] ERROR: Failed to start Access Point!\n", millis());
+    onGoBack();
+    return;
+  }
+
+  delay(100);  // Wait for AP to fully initialize
+
+  // Get AP IP address
+  const IPAddress apIP = WiFi.softAPIP();
+  char ipStr[16];
+  snprintf(ipStr, sizeof(ipStr), "%d.%d.%d.%d", apIP[0], apIP[1], apIP[2], apIP[3]);
+  connectedIP = ipStr;
+  connectedSSID = AP_SSID;
+
+  Serial.printf("[%lu] [WEBACT] Access Point started!\n", millis());
+  Serial.printf("[%lu] [WEBACT] SSID: %s\n", millis(), AP_SSID);
+  Serial.printf("[%lu] [WEBACT] IP: %s\n", millis(), connectedIP.c_str());
+
+  // Start mDNS for hostname resolution
+  if (MDNS.begin(AP_HOSTNAME)) {
+    Serial.printf("[%lu] [WEBACT] mDNS started: http://%s.local/\n", millis(), AP_HOSTNAME);
+  } else {
+    Serial.printf("[%lu] [WEBACT] WARNING: mDNS failed to start\n", millis());
+  }
+
+  // Start DNS server for captive portal behavior
+  // This redirects all DNS queries to our IP, making any domain typed resolve to us
+  dnsServer = new DNSServer();
+  dnsServer->setErrorReplyCode(DNSReplyCode::NoError);
+  dnsServer->start(DNS_PORT, "*", apIP);
+  Serial.printf("[%lu] [WEBACT] DNS server started for captive portal\n", millis());
+
+  Serial.printf("[%lu] [WEBACT] [MEM] Free heap after AP start: %d bytes\n", millis(), ESP.getFreeHeap());
+
+  // Start the web server
+  startWebServer();
+}
+
 void CrossPointWebServerActivity::startWebServer() {
   Serial.printf("[%lu] [WEBACT] Starting web server...\n", millis());
 
@@ -150,20 +270,23 @@ void CrossPointWebServerActivity::stopWebServer() {
 }
 
 void CrossPointWebServerActivity::loop() {
-  // Handle different states
+  if (subActivity) {
-  switch (state) {
+    // Forward loop to subactivity
-    case WebServerActivityState::WIFI_SELECTION:
+    subActivity->loop();
-      // Forward loop to WiFi selection subactivity
+    return;
-      if (wifiSelection) {
+  }
-        wifiSelection->loop();
+
+  // Handle different states
+  if (state == WebServerActivityState::SERVER_RUNNING) {
+    // Handle DNS requests for captive portal (AP mode only)
+    if (isApMode && dnsServer) {
+      dnsServer->processNextRequest();
     }
-      break;
 
-    case WebServerActivityState::SERVER_RUNNING:
     // Handle web server requests - call handleClient multiple times per loop
     // to improve responsiveness and upload throughput
     if (webServer && webServer->isRunning()) {
-        unsigned long timeSinceLastHandleClient = millis() - lastHandleClientTime;
+      const unsigned long timeSinceLastHandleClient = millis() - lastHandleClientTime;
 
       // Log if there's a significant gap between handleClient calls (>100ms)
       if (lastHandleClientTime > 0 && timeSinceLastHandleClient > 100) {
@@ -186,11 +309,6 @@ void CrossPointWebServerActivity::loop() {
       onGoBack();
       return;
     }
-      break;
-
-    case WebServerActivityState::SHUTTING_DOWN:
-      // Do nothing - waiting for cleanup
-      break;
   }
 }
 
@@ -208,36 +326,107 @@ void CrossPointWebServerActivity::displayTaskLoop() {
 
 void CrossPointWebServerActivity::render() const {
   // Only render our own UI when server is running
-  // WiFi selection handles its own rendering
+  // Subactivities handle their own rendering
   if (state == WebServerActivityState::SERVER_RUNNING) {
     renderer.clearScreen();
     renderServerRunning();
     renderer.displayBuffer();
+  } else if (state == WebServerActivityState::AP_STARTING) {
+    renderer.clearScreen();
+    const auto pageHeight = renderer.getScreenHeight();
+    renderer.drawCenteredText(READER_FONT_ID, pageHeight / 2 - 20, "Starting Hotspot...", true, BOLD);
+    renderer.displayBuffer();
+  }
+}
+
+void drawQRCode(const GfxRenderer& renderer, const int x, const int y, const std::string& data) {
+  // Implementation of QR code calculation
+  // The structure to manage the QR code
+  QRCode qrcode;
+  uint8_t qrcodeBytes[qrcode_getBufferSize(4)];
+  Serial.printf("[%lu] [WEBACT] QR Code (%lu): %s\n", millis(), data.length(), data.c_str());
+
+  qrcode_initText(&qrcode, qrcodeBytes, 4, ECC_LOW, data.c_str());
+  const uint8_t px = 6;  // pixels per module
+  for (uint8_t cy = 0; cy < qrcode.size; cy++) {
+    for (uint8_t cx = 0; cx < qrcode.size; cx++) {
+      if (qrcode_getModule(&qrcode, cx, cy)) {
+        // Serial.print("**");
+        renderer.fillRect(x + px * cx, y + px * cy, px, px, true);
+      } else {
+        // Serial.print("  ");
+      }
+    }
+    // Serial.print("\n");
   }
 }
 
 void CrossPointWebServerActivity::renderServerRunning() const {
-  const auto pageWidth = GfxRenderer::getScreenWidth();
+  // Use consistent line spacing
-  const auto pageHeight = GfxRenderer::getScreenHeight();
+  constexpr int LINE_SPACING = 28;  // Space between lines
-  const auto height = renderer.getLineHeight(UI_FONT_ID);
-  const auto top = (pageHeight - height * 5) / 2;
 
-  renderer.drawCenteredText(READER_FONT_ID, top - 30, "File Transfer", true, BOLD);
+  renderer.drawCenteredText(READER_FONT_ID, 15, "File Transfer", true, BOLD);
+
+  if (isApMode) {
+    // AP mode display - center the content block
+    int startY = 55;
+
+    renderer.drawCenteredText(UI_FONT_ID, startY, "Hotspot Mode", true, BOLD);
+
+    std::string ssidInfo = "Network: " + connectedSSID;
+    renderer.drawCenteredText(UI_FONT_ID, startY + LINE_SPACING, ssidInfo.c_str(), true, REGULAR);
+
+    renderer.drawCenteredText(SMALL_FONT_ID, startY + LINE_SPACING * 2, "Connect your device to this WiFi network",
+                              true, REGULAR);
+
+    renderer.drawCenteredText(SMALL_FONT_ID, startY + LINE_SPACING * 3,
+                              "or scan QR code with your phone to connect to Wifi.", true, REGULAR);
+    // Show QR code for URL
+    std::string wifiConfig = std::string("WIFI:T:WPA;S:") + connectedSSID + ";P:" + "" + ";;";
+    drawQRCode(renderer, (480 - 6 * 33) / 2, startY + LINE_SPACING * 4, wifiConfig);
+
+    startY += 6 * 29 + 3 * LINE_SPACING;
+    // Show primary URL (hostname)
+    std::string hostnameUrl = std::string("http://") + AP_HOSTNAME + ".local/";
+    renderer.drawCenteredText(UI_FONT_ID, startY + LINE_SPACING * 3, hostnameUrl.c_str(), true, BOLD);
+
+    // Show IP address as fallback
+    std::string ipUrl = "or http://" + connectedIP + "/";
+    renderer.drawCenteredText(SMALL_FONT_ID, startY + LINE_SPACING * 4, ipUrl.c_str(), true, REGULAR);
+    renderer.drawCenteredText(SMALL_FONT_ID, startY + LINE_SPACING * 5, "Open this URL in your browser", true, REGULAR);
+
+    // Show QR code for URL
+    renderer.drawCenteredText(SMALL_FONT_ID, startY + LINE_SPACING * 6, "or scan QR code with your phone:", true,
+                              REGULAR);
+    drawQRCode(renderer, (480 - 6 * 33) / 2, startY + LINE_SPACING * 7, hostnameUrl);
+  } else {
+    // STA mode display (original behavior)
+    const int startY = 65;
 
     std::string ssidInfo = "Network: " + connectedSSID;
     if (ssidInfo.length() > 28) {
-    ssidInfo = ssidInfo.substr(0, 25) + "...";
+      ssidInfo.replace(25, ssidInfo.length() - 25, "...");
     }
-  renderer.drawCenteredText(UI_FONT_ID, top + 10, ssidInfo.c_str(), true, REGULAR);
+    renderer.drawCenteredText(UI_FONT_ID, startY, ssidInfo.c_str(), true, REGULAR);
 
     std::string ipInfo = "IP Address: " + connectedIP;
-  renderer.drawCenteredText(UI_FONT_ID, top + 40, ipInfo.c_str(), true, REGULAR);
+    renderer.drawCenteredText(UI_FONT_ID, startY + LINE_SPACING, ipInfo.c_str(), true, REGULAR);
 
     // Show web server URL prominently
     std::string webInfo = "http://" + connectedIP + "/";
-  renderer.drawCenteredText(UI_FONT_ID, top + 70, webInfo.c_str(), true, BOLD);
+    renderer.drawCenteredText(UI_FONT_ID, startY + LINE_SPACING * 2, webInfo.c_str(), true, BOLD);
 
-  renderer.drawCenteredText(SMALL_FONT_ID, top + 110, "Open this URL in your browser", true, REGULAR);
+    // Also show hostname URL
+    std::string hostnameUrl = std::string("or http://") + AP_HOSTNAME + ".local/";
+    renderer.drawCenteredText(SMALL_FONT_ID, startY + LINE_SPACING * 3, hostnameUrl.c_str(), true, REGULAR);
 
-  renderer.drawCenteredText(SMALL_FONT_ID, pageHeight - 30, "Press BACK to exit", true, REGULAR);
+    renderer.drawCenteredText(SMALL_FONT_ID, startY + LINE_SPACING * 4, "Open this URL in your browser", true, REGULAR);
+
+    // Show QR code for URL
+    drawQRCode(renderer, (480 - 6 * 33) / 2, startY + LINE_SPACING * 6, webInfo);
+    renderer.drawCenteredText(SMALL_FONT_ID, startY + LINE_SPACING * 5, "or scan QR code with your phone:", true,
+                              REGULAR);
+  }
+
+  renderer.drawButtonHints(UI_FONT_ID, "« Exit", "", "", "");
 }

src/activities/network/CrossPointWebServerActivity.h

@@ -7,13 +7,15 @@
 #include <memory>
 #include <string>
 
-#include "../Activity.h"
+#include "NetworkModeSelectionActivity.h"
-#include "WifiSelectionActivity.h"
+#include "activities/ActivityWithSubactivity.h"
-#include "server/CrossPointWebServer.h"
+#include "network/CrossPointWebServer.h"
 
 // Web server activity states
 enum class WebServerActivityState {
-  WIFI_SELECTION,  // WiFi selection subactivity is active
+  MODE_SELECTION,  // Choosing between Join Network and Create Hotspot
+  WIFI_SELECTION,  // WiFi selection subactivity is active (for Join Network mode)
+  AP_STARTING,     // Starting Access Point mode
   SERVER_RUNNING,  // Web server is running and handling requests
   SHUTTING_DOWN    // Shutting down server and WiFi
 };
@@ -21,27 +23,30 @@ enum class WebServerActivityState {
 /**
  * CrossPointWebServerActivity is the entry point for file transfer functionality.
  * It:
- * - Immediately turns on WiFi and launches WifiSelectionActivity on enter
+ * - First presents a choice between "Join a Network" (STA) and "Create Hotspot" (AP)
- * - When WifiSelectionActivity completes successfully, starts the CrossPointWebServer
+ * - For STA mode: Launches WifiSelectionActivity to connect to an existing network
+ * - For AP mode: Creates an Access Point that clients can connect to
+ * - Starts the CrossPointWebServer when connected
  * - Handles client requests in its loop() function
  * - Cleans up the server and shuts down WiFi on exit
  */
-class CrossPointWebServerActivity final : public Activity {
+class CrossPointWebServerActivity final : public ActivityWithSubactivity {
   TaskHandle_t displayTaskHandle = nullptr;
   SemaphoreHandle_t renderingMutex = nullptr;
   bool updateRequired = false;
-  WebServerActivityState state = WebServerActivityState::WIFI_SELECTION;
+  WebServerActivityState state = WebServerActivityState::MODE_SELECTION;
   const std::function<void()> onGoBack;
 
-  // WiFi selection subactivity
+  // Network mode
-  std::unique_ptr<WifiSelectionActivity> wifiSelection;
+  NetworkMode networkMode = NetworkMode::JOIN_NETWORK;
+  bool isApMode = false;
 
   // Web server - owned by this activity
   std::unique_ptr<CrossPointWebServer> webServer;
 
   // Server status
   std::string connectedIP;
-  std::string connectedSSID;
+  std::string connectedSSID;  // For STA mode: network name, For AP mode: AP name
 
   // Performance monitoring
   unsigned long lastHandleClientTime = 0;
@@ -51,14 +56,16 @@ class CrossPointWebServerActivity final : public Activity {
   void render() const;
   void renderServerRunning() const;
 
+  void onNetworkModeSelected(NetworkMode mode);
   void onWifiSelectionComplete(bool connected);
+  void startAccessPoint();
   void startWebServer();
   void stopWebServer();
 
  public:
   explicit CrossPointWebServerActivity(GfxRenderer& renderer, InputManager& inputManager,
                                        const std::function<void()>& onGoBack)
-      : Activity(renderer, inputManager), onGoBack(onGoBack) {}
+      : ActivityWithSubactivity("CrossPointWebServer", renderer, inputManager), onGoBack(onGoBack) {}
   void onEnter() override;
   void onExit() override;
   void loop() override;

src/activities/network/NetworkModeSelectionActivity.cpp

@@ -0,0 +1,128 @@
+#include "NetworkModeSelectionActivity.h"
+
+#include <GfxRenderer.h>
+#include <InputManager.h>
+
+#include "config.h"
+
+namespace {
+constexpr int MENU_ITEM_COUNT = 2;
+const char* MENU_ITEMS[MENU_ITEM_COUNT] = {"Join a Network", "Create Hotspot"};
+const char* MENU_DESCRIPTIONS[MENU_ITEM_COUNT] = {"Connect to an existing WiFi network",
+                                                  "Create a WiFi network others can join"};
+}  // namespace
+
+void NetworkModeSelectionActivity::taskTrampoline(void* param) {
+  auto* self = static_cast<NetworkModeSelectionActivity*>(param);
+  self->displayTaskLoop();
+}
+
+void NetworkModeSelectionActivity::onEnter() {
+  Activity::onEnter();
+
+  renderingMutex = xSemaphoreCreateMutex();
+
+  // Reset selection
+  selectedIndex = 0;
+
+  // Trigger first update
+  updateRequired = true;
+
+  xTaskCreate(&NetworkModeSelectionActivity::taskTrampoline, "NetworkModeTask",
+              2048,               // Stack size
+              this,               // Parameters
+              1,                  // Priority
+              &displayTaskHandle  // Task handle
+  );
+}
+
+void NetworkModeSelectionActivity::onExit() {
+  Activity::onExit();
+
+  // Wait until not rendering to delete task
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
+  if (displayTaskHandle) {
+    vTaskDelete(displayTaskHandle);
+    displayTaskHandle = nullptr;
+  }
+  vSemaphoreDelete(renderingMutex);
+  renderingMutex = nullptr;
+}
+
+void NetworkModeSelectionActivity::loop() {
+  // Handle back button - cancel
+  if (inputManager.wasPressed(InputManager::BTN_BACK)) {
+    onCancel();
+    return;
+  }
+
+  // Handle confirm button - select current option
+  if (inputManager.wasPressed(InputManager::BTN_CONFIRM)) {
+    const NetworkMode mode = (selectedIndex == 0) ? NetworkMode::JOIN_NETWORK : NetworkMode::CREATE_HOTSPOT;
+    onModeSelected(mode);
+    return;
+  }
+
+  // Handle navigation
+  const bool prevPressed =
+      inputManager.wasPressed(InputManager::BTN_UP) || inputManager.wasPressed(InputManager::BTN_LEFT);
+  const bool nextPressed =
+      inputManager.wasPressed(InputManager::BTN_DOWN) || inputManager.wasPressed(InputManager::BTN_RIGHT);
+
+  if (prevPressed) {
+    selectedIndex = (selectedIndex + MENU_ITEM_COUNT - 1) % MENU_ITEM_COUNT;
+    updateRequired = true;
+  } else if (nextPressed) {
+    selectedIndex = (selectedIndex + 1) % MENU_ITEM_COUNT;
+    updateRequired = true;
+  }
+}
+
+void NetworkModeSelectionActivity::displayTaskLoop() {
+  while (true) {
+    if (updateRequired) {
+      updateRequired = false;
+      xSemaphoreTake(renderingMutex, portMAX_DELAY);
+      render();
+      xSemaphoreGive(renderingMutex);
+    }
+    vTaskDelay(10 / portTICK_PERIOD_MS);
+  }
+}
+
+void NetworkModeSelectionActivity::render() const {
+  renderer.clearScreen();
+
+  const auto pageWidth = renderer.getScreenWidth();
+  const auto pageHeight = renderer.getScreenHeight();
+
+  // Draw header
+  renderer.drawCenteredText(READER_FONT_ID, 10, "File Transfer", true, BOLD);
+
+  // Draw subtitle
+  renderer.drawCenteredText(UI_FONT_ID, 50, "How would you like to connect?", true, REGULAR);
+
+  // Draw menu items centered on screen
+  constexpr int itemHeight = 50;  // Height for each menu item (including description)
+  const int startY = (pageHeight - (MENU_ITEM_COUNT * itemHeight)) / 2 + 10;
+
+  for (int i = 0; i < MENU_ITEM_COUNT; i++) {
+    const int itemY = startY + i * itemHeight;
+    const bool isSelected = (i == selectedIndex);
+
+    // Draw selection highlight (black fill) for selected item
+    if (isSelected) {
+      renderer.fillRect(20, itemY - 2, pageWidth - 40, itemHeight - 6);
+    }
+
+    // Draw text: black=false (white text) when selected (on black background)
+    //            black=true (black text) when not selected (on white background)
+    renderer.drawText(UI_FONT_ID, 30, itemY, MENU_ITEMS[i], /*black=*/!isSelected);
+    renderer.drawText(SMALL_FONT_ID, 30, itemY + 22, MENU_DESCRIPTIONS[i], /*black=*/!isSelected);
+  }
+
+  // Draw help text at bottom
+  renderer.drawButtonHints(UI_FONT_ID, "« Back", "Select", "", "");
+
+  renderer.displayBuffer();
+}

src/activities/network/NetworkModeSelectionActivity.h

@@ -0,0 +1,41 @@
+#pragma once
+#include <freertos/FreeRTOS.h>
+#include <freertos/semphr.h>
+#include <freertos/task.h>
+
+#include <functional>
+
+#include "../Activity.h"
+
+// Enum for network mode selection
+enum class NetworkMode { JOIN_NETWORK, CREATE_HOTSPOT };
+
+/**
+ * NetworkModeSelectionActivity presents the user with a choice:
+ * - "Join a Network" - Connect to an existing WiFi network (STA mode)
+ * - "Create Hotspot" - Create an Access Point that others can connect to (AP mode)
+ *
+ * The onModeSelected callback is called with the user's choice.
+ * The onCancel callback is called if the user presses back.
+ */
+class NetworkModeSelectionActivity final : public Activity {
+  TaskHandle_t displayTaskHandle = nullptr;
+  SemaphoreHandle_t renderingMutex = nullptr;
+  int selectedIndex = 0;
+  bool updateRequired = false;
+  const std::function<void(NetworkMode)> onModeSelected;
+  const std::function<void()> onCancel;
+
+  static void taskTrampoline(void* param);
+  [[noreturn]] void displayTaskLoop();
+  void render() const;
+
+ public:
+  explicit NetworkModeSelectionActivity(GfxRenderer& renderer, InputManager& inputManager,
+                                        const std::function<void(NetworkMode)>& onModeSelected,
+                                        const std::function<void()>& onCancel)
+      : Activity("NetworkModeSelection", renderer, inputManager), onModeSelected(onModeSelected), onCancel(onCancel) {}
+  void onEnter() override;
+  void onExit() override;
+  void loop() override;
+};

src/activities/network/WifiSelectionActivity.cpp

@@ -6,6 +6,7 @@
 #include <map>
 
 #include "WifiCredentialStore.h"
+#include "activities/util/KeyboardEntryActivity.h"
 #include "config.h"
 
 void WifiSelectionActivity::taskTrampoline(void* param) {
@@ -14,10 +15,14 @@ void WifiSelectionActivity::taskTrampoline(void* param) {
 }
 
 void WifiSelectionActivity::onEnter() {
+  Activity::onEnter();
+
   renderingMutex = xSemaphoreCreateMutex();
 
-  // Load saved WiFi credentials
+  // Load saved WiFi credentials - SD card operations need lock as we use SPI for both
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
   WIFI_STORE.loadFromFile();
+  xSemaphoreGive(renderingMutex);
 
   // Reset state
   selectedNetworkIndex = 0;
@@ -30,7 +35,6 @@ void WifiSelectionActivity::onEnter() {
   usedSavedPassword = false;
   savePromptSelection = 0;
   forgetPromptSelection = 0;
-  keyboard.reset();
 
   // Trigger first update to show scanning message
   updateRequired = true;
@@ -47,7 +51,8 @@ void WifiSelectionActivity::onEnter() {
 }
 
 void WifiSelectionActivity::onExit() {
-  Serial.printf("[%lu] [WIFI] ========== WifiSelectionActivity onExit START ==========\n", millis());
+  Activity::onExit();
+
   Serial.printf("[%lu] [WIFI] [MEM] Free heap at onExit start: %d bytes\n", millis(), ESP.getFreeHeap());
 
   // Stop any ongoing WiFi scan
@@ -78,7 +83,6 @@ void WifiSelectionActivity::onExit() {
   Serial.printf("[%lu] [WIFI] Mutex deleted\n", millis());
 
   Serial.printf("[%lu] [WIFI] [MEM] Free heap at onExit end: %d bytes\n", millis(), ESP.getFreeHeap());
-  Serial.printf("[%lu] [WIFI] ========== WifiSelectionActivity onExit COMPLETE ==========\n", millis());
 }
 
 void WifiSelectionActivity::startWifiScan() {
@@ -96,7 +100,7 @@ void WifiSelectionActivity::startWifiScan() {
 }
 
 void WifiSelectionActivity::processWifiScanResults() {
-  int16_t scanResult = WiFi.scanComplete();
+  const int16_t scanResult = WiFi.scanComplete();
 
   if (scanResult == WIFI_SCAN_RUNNING) {
     // Scan still in progress
@@ -115,7 +119,7 @@ void WifiSelectionActivity::processWifiScanResults() {
 
   for (int i = 0; i < scanResult; i++) {
     std::string ssid = WiFi.SSID(i).c_str();
-    int32_t rssi = WiFi.RSSI(i);
+    const int32_t rssi = WiFi.RSSI(i);
 
     // Skip hidden networks (empty SSID)
     if (ssid.empty()) {
@@ -138,6 +142,7 @@ void WifiSelectionActivity::processWifiScanResults() {
   // Convert map to vector
   networks.clear();
   for (const auto& pair : uniqueNetworks) {
+    // cppcheck-suppress useStlAlgorithm
     networks.push_back(pair.second);
   }
 
@@ -145,13 +150,18 @@ void WifiSelectionActivity::processWifiScanResults() {
   std::sort(networks.begin(), networks.end(),
             [](const WifiNetworkInfo& a, const WifiNetworkInfo& b) { return a.rssi > b.rssi; });
 
+  // Show networks with PW first
+  std::sort(networks.begin(), networks.end(), [](const WifiNetworkInfo& a, const WifiNetworkInfo& b) {
+    return a.hasSavedPassword && !b.hasSavedPassword;
+  });
+
   WiFi.scanDelete();
   state = WifiSelectionState::NETWORK_LIST;
   selectedNetworkIndex = 0;
   updateRequired = true;
 }
 
-void WifiSelectionActivity::selectNetwork(int index) {
+void WifiSelectionActivity::selectNetwork(const int index) {
   if (index < 0 || index >= static_cast<int>(networks.size())) {
     return;
   }
@@ -177,11 +187,21 @@ void WifiSelectionActivity::selectNetwork(int index) {
   if (selectedRequiresPassword) {
     // Show password entry
     state = WifiSelectionState::PASSWORD_ENTRY;
-    keyboard.reset(new KeyboardEntryActivity(renderer, inputManager, "Enter WiFi Password",
+    enterNewActivity(new KeyboardEntryActivity(
+        renderer, inputManager, "Enter WiFi Password",
         "",     // No initial text
+        50,     // Y position
         64,     // Max password length
-                                             false  // Show password by default (hard keyboard to use)
+        false,  // Show password by default (hard keyboard to use)
-                                             ));
+        [this](const std::string& text) {
+          enteredPassword = text;
+          exitActivity();
+        },
+        [this] {
+          state = WifiSelectionState::NETWORK_LIST;
+          updateRequired = true;
+          exitActivity();
+        }));
     updateRequired = true;
   } else {
     // Connect directly for open networks
@@ -198,11 +218,6 @@ void WifiSelectionActivity::attemptConnection() {
 
   WiFi.mode(WIFI_STA);
 
-  // Get password from keyboard if we just entered it
-  if (keyboard && !usedSavedPassword) {
-    enteredPassword = keyboard->getText();
-  }
-
   if (selectedRequiresPassword && !enteredPassword.empty()) {
     WiFi.begin(selectedSSID.c_str(), enteredPassword.c_str());
   } else {
@@ -215,7 +230,7 @@ void WifiSelectionActivity::checkConnectionStatus() {
     return;
   }
 
-  wl_status_t status = WiFi.status();
+  const wl_status_t status = WiFi.status();
 
   if (status == WL_CONNECTED) {
     // Successfully connected
@@ -259,6 +274,11 @@ void WifiSelectionActivity::checkConnectionStatus() {
 }
 
 void WifiSelectionActivity::loop() {
+  if (subActivity) {
+    subActivity->loop();
+    return;
+  }
+
   // Check scan progress
   if (state == WifiSelectionState::SCANNING) {
     processWifiScanResults();
@@ -271,26 +291,12 @@ void WifiSelectionActivity::loop() {
     return;
   }
 
-  // Handle password entry state
+  if (state == WifiSelectionState::PASSWORD_ENTRY) {
-  if (state == WifiSelectionState::PASSWORD_ENTRY && keyboard) {
+    // Reach here once password entry finished in subactivity
-    keyboard->handleInput();
-
-    if (keyboard->isComplete()) {
     attemptConnection();
     return;
   }
 
-    if (keyboard->isCancelled()) {
-      state = WifiSelectionState::NETWORK_LIST;
-      keyboard.reset();
-      updateRequired = true;
-      return;
-    }
-
-    updateRequired = true;
-    return;
-  }
-
   // Handle save prompt state
   if (state == WifiSelectionState::SAVE_PROMPT) {
     if (inputManager.wasPressed(InputManager::BTN_LEFT) || inputManager.wasPressed(InputManager::BTN_UP)) {
@@ -306,7 +312,9 @@ void WifiSelectionActivity::loop() {
     } else if (inputManager.wasPressed(InputManager::BTN_CONFIRM)) {
       if (savePromptSelection == 0) {
         // User chose "Yes" - save the password
+        xSemaphoreTake(renderingMutex, portMAX_DELAY);
         WIFI_STORE.addCredential(selectedSSID, enteredPassword);
+        xSemaphoreGive(renderingMutex);
       }
       // Complete - parent will start web server
       onComplete(true);
@@ -332,13 +340,14 @@ void WifiSelectionActivity::loop() {
     } else if (inputManager.wasPressed(InputManager::BTN_CONFIRM)) {
       if (forgetPromptSelection == 0) {
         // User chose "Yes" - forget the network
+        xSemaphoreTake(renderingMutex, portMAX_DELAY);
         WIFI_STORE.removeCredential(selectedSSID);
+        xSemaphoreGive(renderingMutex);
         // Update the network list to reflect the change
-        for (auto& network : networks) {
+        const auto network = find_if(networks.begin(), networks.end(),
-          if (network.ssid == selectedSSID) {
+                                     [this](const WifiNetworkInfo& net) { return net.ssid == selectedSSID; });
-            network.hasSavedPassword = false;
+        if (network != networks.end()) {
-            break;
+          network->hasSavedPassword = false;
-          }
         }
       }
       // Go back to network list
@@ -408,15 +417,18 @@ void WifiSelectionActivity::loop() {
   }
 }
 
-std::string WifiSelectionActivity::getSignalStrengthIndicator(int32_t rssi) const {
+std::string WifiSelectionActivity::getSignalStrengthIndicator(const int32_t rssi) const {
   // Convert RSSI to signal bars representation
   if (rssi >= -50) {
     return "||||";  // Excellent
-  } else if (rssi >= -60) {
+  }
+  if (rssi >= -60) {
     return "||| ";  // Good
-  } else if (rssi >= -70) {
+  }
+  if (rssi >= -70) {
     return "||  ";  // Fair
-  } else if (rssi >= -80) {
+  }
+  if (rssi >= -80) {
     return "|   ";  // Weak
   }
   return "    ";  // Very weak
@@ -424,6 +436,10 @@ std::string WifiSelectionActivity::getSignalStrengthIndicator(int32_t rssi) cons
 
 void WifiSelectionActivity::displayTaskLoop() {
   while (true) {
+    if (subActivity) {
+      return;
+    }
+
     if (updateRequired) {
       updateRequired = false;
       xSemaphoreTake(renderingMutex, portMAX_DELAY);
@@ -444,9 +460,6 @@ void WifiSelectionActivity::render() const {
     case WifiSelectionState::NETWORK_LIST:
       renderNetworkList();
       break;
-    case WifiSelectionState::PASSWORD_ENTRY:
-      renderPasswordEntry();
-      break;
     case WifiSelectionState::CONNECTING:
       renderConnecting();
       break;
@@ -468,8 +481,8 @@ void WifiSelectionActivity::render() const {
 }
 
 void WifiSelectionActivity::renderNetworkList() const {
-  const auto pageWidth = GfxRenderer::getScreenWidth();
+  const auto pageWidth = renderer.getScreenWidth();
-  const auto pageHeight = GfxRenderer::getScreenHeight();
+  const auto pageHeight = renderer.getScreenHeight();
 
   // Draw header
   renderer.drawCenteredText(READER_FONT_ID, 10, "WiFi Networks", true, BOLD);
@@ -482,8 +495,8 @@ void WifiSelectionActivity::renderNetworkList() const {
     renderer.drawCenteredText(SMALL_FONT_ID, top + height + 10, "Press OK to scan again", true, REGULAR);
   } else {
     // Calculate how many networks we can display
-    const int startY = 60;
+    constexpr int startY = 60;
-    const int lineHeight = 25;
+    constexpr int lineHeight = 25;
     const int maxVisibleNetworks = (pageHeight - startY - 40) / lineHeight;
 
     // Calculate scroll offset to keep selected item visible
@@ -506,7 +519,7 @@ void WifiSelectionActivity::renderNetworkList() const {
       // Draw network name (truncate if too long)
       std::string displayName = network.ssid;
       if (displayName.length() > 16) {
-        displayName = displayName.substr(0, 13) + "...";
+        displayName.replace(13, displayName.length() - 13, "...");
       }
       renderer.drawText(UI_FONT_ID, 20, networkY, displayName.c_str());
 
@@ -536,53 +549,34 @@ void WifiSelectionActivity::renderNetworkList() const {
     // Show network count
     char countStr[32];
     snprintf(countStr, sizeof(countStr), "%zu networks found", networks.size());
-    renderer.drawText(SMALL_FONT_ID, 20, pageHeight - 45, countStr);
+    renderer.drawText(SMALL_FONT_ID, 20, pageHeight - 90, countStr);
   }
 
   // Draw help text
-  renderer.drawText(SMALL_FONT_ID, 20, pageHeight - 30, "OK: Connect | * = Encrypted | + = Saved");
+  renderer.drawText(SMALL_FONT_ID, 20, pageHeight - 75, "* = Encrypted | + = Saved");
-}
+  renderer.drawButtonHints(UI_FONT_ID, "« Back", "Connect", "", "");
-
-void WifiSelectionActivity::renderPasswordEntry() const {
-  const auto pageHeight = GfxRenderer::getScreenHeight();
-
-  // Draw header
-  renderer.drawCenteredText(READER_FONT_ID, 5, "WiFi Password", true, BOLD);
-
-  // Draw network name with good spacing from header
-  std::string networkInfo = "Network: " + selectedSSID;
-  if (networkInfo.length() > 30) {
-    networkInfo = networkInfo.substr(0, 27) + "...";
-  }
-  renderer.drawCenteredText(UI_FONT_ID, 38, networkInfo.c_str(), true, REGULAR);
-
-  // Draw keyboard
-  if (keyboard) {
-    keyboard->render(58);
-  }
 }
 
 void WifiSelectionActivity::renderConnecting() const {
-  const auto pageHeight = GfxRenderer::getScreenHeight();
+  const auto pageHeight = renderer.getScreenHeight();
   const auto height = renderer.getLineHeight(UI_FONT_ID);
   const auto top = (pageHeight - height) / 2;
 
   if (state == WifiSelectionState::SCANNING) {
     renderer.drawCenteredText(UI_FONT_ID, top, "Scanning...", true, REGULAR);
   } else {
-    renderer.drawCenteredText(READER_FONT_ID, top - 30, "Connecting...", true, BOLD);
+    renderer.drawCenteredText(READER_FONT_ID, top - 40, "Connecting...", true, BOLD);
 
     std::string ssidInfo = "to " + selectedSSID;
     if (ssidInfo.length() > 25) {
-      ssidInfo = ssidInfo.substr(0, 22) + "...";
+      ssidInfo.replace(22, ssidInfo.length() - 22, "...");
     }
     renderer.drawCenteredText(UI_FONT_ID, top, ssidInfo.c_str(), true, REGULAR);
   }
 }
 
 void WifiSelectionActivity::renderConnected() const {
-  const auto pageWidth = GfxRenderer::getScreenWidth();
+  const auto pageHeight = renderer.getScreenHeight();
-  const auto pageHeight = GfxRenderer::getScreenHeight();
   const auto height = renderer.getLineHeight(UI_FONT_ID);
   const auto top = (pageHeight - height * 4) / 2;
 
@@ -590,19 +584,19 @@ void WifiSelectionActivity::renderConnected() const {
 
   std::string ssidInfo = "Network: " + selectedSSID;
   if (ssidInfo.length() > 28) {
-    ssidInfo = ssidInfo.substr(0, 25) + "...";
+    ssidInfo.replace(25, ssidInfo.length() - 25, "...");
   }
   renderer.drawCenteredText(UI_FONT_ID, top + 10, ssidInfo.c_str(), true, REGULAR);
 
-  std::string ipInfo = "IP Address: " + connectedIP;
+  const std::string ipInfo = "IP Address: " + connectedIP;
   renderer.drawCenteredText(UI_FONT_ID, top + 40, ipInfo.c_str(), true, REGULAR);
 
   renderer.drawCenteredText(SMALL_FONT_ID, pageHeight - 30, "Press any button to continue", true, REGULAR);
 }
 
 void WifiSelectionActivity::renderSavePrompt() const {
-  const auto pageWidth = GfxRenderer::getScreenWidth();
+  const auto pageWidth = renderer.getScreenWidth();
-  const auto pageHeight = GfxRenderer::getScreenHeight();
+  const auto pageHeight = renderer.getScreenHeight();
   const auto height = renderer.getLineHeight(UI_FONT_ID);
   const auto top = (pageHeight - height * 3) / 2;
 
@@ -610,7 +604,7 @@ void WifiSelectionActivity::renderSavePrompt() const {
 
   std::string ssidInfo = "Network: " + selectedSSID;
   if (ssidInfo.length() > 28) {
-    ssidInfo = ssidInfo.substr(0, 25) + "...";
+    ssidInfo.replace(25, ssidInfo.length() - 25, "...");
   }
   renderer.drawCenteredText(UI_FONT_ID, top, ssidInfo.c_str(), true, REGULAR);
 
@@ -618,9 +612,9 @@ void WifiSelectionActivity::renderSavePrompt() const {
 
   // Draw Yes/No buttons
   const int buttonY = top + 80;
-  const int buttonWidth = 60;
+  constexpr int buttonWidth = 60;
-  const int buttonSpacing = 30;
+  constexpr int buttonSpacing = 30;
-  const int totalWidth = buttonWidth * 2 + buttonSpacing;
+  constexpr int totalWidth = buttonWidth * 2 + buttonSpacing;
   const int startX = (pageWidth - totalWidth) / 2;
 
   // Draw "Yes" button
@@ -641,7 +635,7 @@ void WifiSelectionActivity::renderSavePrompt() const {
 }
 
 void WifiSelectionActivity::renderConnectionFailed() const {
-  const auto pageHeight = GfxRenderer::getScreenHeight();
+  const auto pageHeight = renderer.getScreenHeight();
   const auto height = renderer.getLineHeight(UI_FONT_ID);
   const auto top = (pageHeight - height * 2) / 2;
 
@@ -651,8 +645,8 @@ void WifiSelectionActivity::renderConnectionFailed() const {
 }
 
 void WifiSelectionActivity::renderForgetPrompt() const {
-  const auto pageWidth = GfxRenderer::getScreenWidth();
+  const auto pageWidth = renderer.getScreenWidth();
-  const auto pageHeight = GfxRenderer::getScreenHeight();
+  const auto pageHeight = renderer.getScreenHeight();
   const auto height = renderer.getLineHeight(UI_FONT_ID);
   const auto top = (pageHeight - height * 3) / 2;
 
@@ -660,7 +654,7 @@ void WifiSelectionActivity::renderForgetPrompt() const {
 
   std::string ssidInfo = "Network: " + selectedSSID;
   if (ssidInfo.length() > 28) {
-    ssidInfo = ssidInfo.substr(0, 25) + "...";
+    ssidInfo.replace(25, ssidInfo.length() - 25, "...");
   }
   renderer.drawCenteredText(UI_FONT_ID, top, ssidInfo.c_str(), true, REGULAR);
 
@@ -668,9 +662,9 @@ void WifiSelectionActivity::renderForgetPrompt() const {
 
   // Draw Yes/No buttons
   const int buttonY = top + 80;
-  const int buttonWidth = 60;
+  constexpr int buttonWidth = 60;
-  const int buttonSpacing = 30;
+  constexpr int buttonSpacing = 30;
-  const int totalWidth = buttonWidth * 2 + buttonSpacing;
+  constexpr int totalWidth = buttonWidth * 2 + buttonSpacing;
   const int startX = (pageWidth - totalWidth) / 2;
 
   // Draw "Yes" button

src/activities/network/WifiSelectionActivity.h

@@ -9,8 +9,7 @@
 #include <string>
 #include <vector>
 
-#include "../Activity.h"
+#include "activities/ActivityWithSubactivity.h"
-#include "../util/KeyboardEntryActivity.h"
 
 // Structure to hold WiFi network information
 struct WifiNetworkInfo {
@@ -43,7 +42,7 @@ enum class WifiSelectionState {
  *
  * The onComplete callback receives true if connected successfully, false if cancelled.
  */
-class WifiSelectionActivity final : public Activity {
+class WifiSelectionActivity final : public ActivityWithSubactivity {
   TaskHandle_t displayTaskHandle = nullptr;
   SemaphoreHandle_t renderingMutex = nullptr;
   bool updateRequired = false;
@@ -56,9 +55,6 @@ class WifiSelectionActivity final : public Activity {
   std::string selectedSSID;
   bool selectedRequiresPassword = false;
 
-  // On-screen keyboard for password entry
-  std::unique_ptr<KeyboardEntryActivity> keyboard;
-
   // Connection result
   std::string connectedIP;
   std::string connectionError;
@@ -98,7 +94,7 @@ class WifiSelectionActivity final : public Activity {
  public:
   explicit WifiSelectionActivity(GfxRenderer& renderer, InputManager& inputManager,
                                  const std::function<void(bool connected)>& onComplete)
-      : Activity(renderer, inputManager), onComplete(onComplete) {}
+      : ActivityWithSubactivity("WifiSelection", renderer, inputManager), onComplete(onComplete) {}
   void onEnter() override;
   void onExit() override;
   void loop() override;

src/activities/reader/EpubReaderActivity.cpp

@@ -1,17 +1,20 @@
 #include "EpubReaderActivity.h"
 
 #include <Epub/Page.h>
+#include <FsHelpers.h>
 #include <GfxRenderer.h>
-#include <SD.h>
+#include <InputManager.h>
 
 #include "Battery.h"
 #include "CrossPointSettings.h"
+#include "CrossPointState.h"
 #include "EpubReaderChapterSelectionActivity.h"
 #include "config.h"
 
 namespace {
 constexpr int pagesPerRefresh = 15;
 constexpr unsigned long skipChapterMs = 700;
+constexpr unsigned long goHomeMs = 1000;
 constexpr float lineCompression = 0.95f;
 constexpr int marginTop = 8;
 constexpr int marginRight = 10;
@@ -25,6 +28,8 @@ void EpubReaderActivity::taskTrampoline(void* param) {
 }
 
 void EpubReaderActivity::onEnter() {
+  ActivityWithSubactivity::onEnter();
+
   if (!epub) {
     return;
   }
@@ -44,8 +49,8 @@ void EpubReaderActivity::onEnter() {
 
   epub->setupCacheDir();
 
-  File f = SD.open((epub->getCachePath() + "/progress.bin").c_str());
+  File f;
-  if (f) {
+  if (FsHelpers::openFileForRead("ERS", epub->getCachePath() + "/progress.bin", f)) {
     uint8_t data[4];
     if (f.read(data, 4) == 4) {
       currentSpineIndex = data[0] + (data[1] << 8);
@@ -55,6 +60,10 @@ void EpubReaderActivity::onEnter() {
     f.close();
   }
 
+  // Save current epub as last opened epub
+  APP_STATE.openEpubPath = epub->getPath();
+  APP_STATE.saveToFile();
+
   // Trigger first update
   updateRequired = true;
 
@@ -67,6 +76,8 @@ void EpubReaderActivity::onEnter() {
 }
 
 void EpubReaderActivity::onExit() {
+  ActivityWithSubactivity::onExit();
+
   // Reset orientation back to portrait for the rest of the UI
   GfxRenderer::setOrientation(GfxRenderer::Orientation::Portrait);
 
@@ -84,8 +95,8 @@ void EpubReaderActivity::onExit() {
 
 void EpubReaderActivity::loop() {
   // Pass input responsibility to sub activity if exists
-  if (subAcitivity) {
+  if (subActivity) {
-    subAcitivity->loop();
+    subActivity->loop();
     return;
   }
 
@@ -93,11 +104,11 @@ void EpubReaderActivity::loop() {
   if (inputManager.wasPressed(InputManager::BTN_CONFIRM)) {
     // Don't start activity transition while rendering
     xSemaphoreTake(renderingMutex, portMAX_DELAY);
-    subAcitivity.reset(new EpubReaderChapterSelectionActivity(
+    exitActivity();
+    enterNewActivity(new EpubReaderChapterSelectionActivity(
         this->renderer, this->inputManager, epub, currentSpineIndex,
         [this] {
-          subAcitivity->onExit();
+          exitActivity();
-          subAcitivity.reset();
           updateRequired = true;
         },
         [this](const int newSpineIndex) {
@@ -106,15 +117,20 @@ void EpubReaderActivity::loop() {
             nextPageNumber = 0;
             section.reset();
           }
-          subAcitivity->onExit();
+          exitActivity();
-          subAcitivity.reset();
           updateRequired = true;
         }));
-    subAcitivity->onEnter();
     xSemaphoreGive(renderingMutex);
   }
 
-  if (inputManager.wasPressed(InputManager::BTN_BACK)) {
+  // Long press BACK (1s+) goes directly to home
+  if (inputManager.isPressed(InputManager::BTN_BACK) && inputManager.getHeldTime() >= goHomeMs) {
+    onGoHome();
+    return;
+  }
+
+  // Short press BACK goes to file selection
+  if (inputManager.wasReleased(InputManager::BTN_BACK) && inputManager.getHeldTime() < goHomeMs) {
     onGoBack();
     return;
   }
@@ -218,7 +234,7 @@ void EpubReaderActivity::renderScreen() {
   }
 
   if (!section) {
-    const auto filepath = epub->getSpineItem(currentSpineIndex);
+    const auto filepath = epub->getSpineItem(currentSpineIndex).href;
     Serial.printf("[%lu] [ERS] Loading file: %s, index: %d\n", millis(), filepath.c_str(), currentSpineIndex);
     section = std::unique_ptr<Section>(new Section(epub, currentSpineIndex, renderer));
     if (!section->loadCacheMetadata(READER_FONT_ID, lineCompression, marginTop, marginRight, marginBottom, marginLeft,
@@ -226,24 +242,52 @@ void EpubReaderActivity::renderScreen() {
                                     GfxRenderer::getScreenHeight())) {
       Serial.printf("[%lu] [ERS] Cache not found, building...\n", millis());
 
-      {
+      // Progress bar dimensions
+      constexpr int barWidth = 200;
+      constexpr int barHeight = 10;
+      constexpr int boxMargin = 20;
       const int textWidth = renderer.getTextWidth(READER_FONT_ID, "Indexing...");
-        constexpr int margin = 20;
+      const int boxWidthWithBar = (barWidth > textWidth ? barWidth : textWidth) + boxMargin * 2;
-        const int x = (GfxRenderer::getScreenWidth() - textWidth - margin * 2) / 2;
+      const int boxWidthNoBar = textWidth + boxMargin * 2;
-        constexpr int y = 50;
+      const int boxHeightWithBar = renderer.getLineHeight(READER_FONT_ID) + barHeight + boxMargin * 3;
-        const int w = textWidth + margin * 2;
+      const int boxHeightNoBar = renderer.getLineHeight(READER_FONT_ID) + boxMargin * 2;
-        const int h = renderer.getLineHeight(READER_FONT_ID) + margin * 2;
+      const int boxXWithBar = (GfxRenderer::getScreenWidth() - boxWidthWithBar) / 2;
-        renderer.fillRect(x, y, w, h, false);
+      const int boxXNoBar = (GfxRenderer::getScreenWidth() - boxWidthNoBar) / 2;
-        renderer.drawText(READER_FONT_ID, x + margin, y + margin, "Indexing...");
+      constexpr int boxY = 50;
-        renderer.drawRect(x + 5, y + 5, w - 10, h - 10);
+      const int barX = boxXWithBar + (boxWidthWithBar - barWidth) / 2;
+      const int barY = boxY + renderer.getLineHeight(READER_FONT_ID) + boxMargin * 2;
+
+      // Always show "Indexing..." text first
+      {
+        renderer.fillRect(boxXNoBar, boxY, boxWidthNoBar, boxHeightNoBar, false);
+        renderer.drawText(READER_FONT_ID, boxXNoBar + boxMargin, boxY + boxMargin, "Indexing...");
+        renderer.drawRect(boxXNoBar + 5, boxY + 5, boxWidthNoBar - 10, boxHeightNoBar - 10);
         renderer.displayBuffer();
         pagesUntilFullRefresh = 0;
       }
 
       section->setupCacheDir();
+
+      // Setup callback - only called for chapters >= 50KB, redraws with progress bar
+      auto progressSetup = [this, boxXWithBar, boxWidthWithBar, boxHeightWithBar, boxMargin, barX, barY, barWidth,
+                            barHeight]() {
+        renderer.fillRect(boxXWithBar, boxY, boxWidthWithBar, boxHeightWithBar, false);
+        renderer.drawText(READER_FONT_ID, boxXWithBar + boxMargin, boxY + boxMargin, "Indexing...");
+        renderer.drawRect(boxXWithBar + 5, boxY + 5, boxWidthWithBar - 10, boxHeightWithBar - 10);
+        renderer.drawRect(barX, barY, barWidth, barHeight);
+        renderer.displayBuffer();
+      };
+
+      // Progress callback to update progress bar
+      auto progressCallback = [this, barX, barY, barWidth, barHeight](int progress) {
+        const int fillWidth = (barWidth - 2) * progress / 100;
+        renderer.fillRect(barX + 1, barY + 1, fillWidth, barHeight - 2, true);
+        renderer.displayBuffer(EInkDisplay::FAST_REFRESH);
+      };
+
       if (!section->persistPageDataToSD(READER_FONT_ID, lineCompression, marginTop, marginRight, marginBottom,
                                         marginLeft, SETTINGS.extraParagraphSpacing, GfxRenderer::getScreenWidth(),
-                                        GfxRenderer::getScreenHeight())) {
+                                        GfxRenderer::getScreenHeight(), progressSetup, progressCallback)) {
         Serial.printf("[%lu] [ERS] Failed to persist page data to SD\n", millis());
         section.reset();
         return;
@@ -290,7 +334,8 @@ void EpubReaderActivity::renderScreen() {
     Serial.printf("[%lu] [ERS] Rendered page in %dms\n", millis(), millis() - start);
   }
 
-  File f = SD.open((epub->getCachePath() + "/progress.bin").c_str(), FILE_WRITE);
+  File f;
+  if (FsHelpers::openFileForWrite("ERS", epub->getCachePath() + "/progress.bin", f)) {
     uint8_t data[4];
     data[0] = currentSpineIndex & 0xFF;
     data[1] = (currentSpineIndex >> 8) & 0xFF;
@@ -298,6 +343,7 @@ void EpubReaderActivity::renderScreen() {
     data[3] = (section->currentPage >> 8) & 0xFF;
     f.write(data, 4);
     f.close();
+  }
 }
 
 void EpubReaderActivity::renderContents(std::unique_ptr<Page> page) {
@@ -338,25 +384,37 @@ void EpubReaderActivity::renderContents(std::unique_ptr<Page> page) {
 }
 
 void EpubReaderActivity::renderStatusBar() const {
+  // determine visible status bar elements
+  const bool showProgress = SETTINGS.statusBar == CrossPointSettings::STATUS_BAR_MODE::FULL;
+  const bool showBattery = SETTINGS.statusBar == CrossPointSettings::STATUS_BAR_MODE::NO_PROGRESS ||
+                           SETTINGS.statusBar == CrossPointSettings::STATUS_BAR_MODE::FULL;
+  const bool showChapterTitle = SETTINGS.statusBar == CrossPointSettings::STATUS_BAR_MODE::NO_PROGRESS ||
+                                SETTINGS.statusBar == CrossPointSettings::STATUS_BAR_MODE::FULL;
+
   // Position status bar near the bottom of the logical screen, regardless of orientation
   const auto screenHeight = GfxRenderer::getScreenHeight();
   const auto textY = screenHeight - 24;
+  int percentageTextWidth = 0;
+  int progressTextWidth = 0;
 
+  if (showProgress) {
     // Calculate progress in book
-  float sectionChapterProg = static_cast<float>(section->currentPage) / section->pageCount;
+    const float sectionChapterProg = static_cast<float>(section->currentPage) / section->pageCount;
-  uint8_t bookProgress = epub->calculateProgress(currentSpineIndex, sectionChapterProg);
+    const uint8_t bookProgress = epub->calculateProgress(currentSpineIndex, sectionChapterProg);
 
     // Right aligned text for progress counter
     const std::string progress = std::to_string(section->currentPage + 1) + "/" + std::to_string(section->pageCount) +
                                  "  " + std::to_string(bookProgress) + "%";
-  const auto progressTextWidth = renderer.getTextWidth(SMALL_FONT_ID, progress.c_str());
+    progressTextWidth = renderer.getTextWidth(SMALL_FONT_ID, progress.c_str());
     renderer.drawText(SMALL_FONT_ID, GfxRenderer::getScreenWidth() - marginRight - progressTextWidth, textY,
                       progress.c_str());
+  }
 
+  if (showBattery) {
     // Left aligned battery icon and percentage
     const uint16_t percentage = battery.readPercentage();
     const auto percentageText = std::to_string(percentage) + "%";
-  const auto percentageTextWidth = renderer.getTextWidth(SMALL_FONT_ID, percentageText.c_str());
+    percentageTextWidth = renderer.getTextWidth(SMALL_FONT_ID, percentageText.c_str());
     renderer.drawText(SMALL_FONT_ID, 20 + marginLeft, textY, percentageText.c_str());
 
     // 1 column on left, 2 columns on right, 5 columns of battery body
@@ -383,7 +441,9 @@ void EpubReaderActivity::renderStatusBar() const {
       filledWidth = batteryWidth - 5;  // Ensure we don't overflow
     }
     renderer.fillRect(x + 1, y + 1, filledWidth, batteryHeight - 2);
+  }
 
+  if (showChapterTitle) {
     // Centered chatper title text
     // Page width minus existing content with 30px padding on each side
     const int titleMarginLeft = 20 + percentageTextWidth + 30 + marginLeft;
@@ -401,10 +461,11 @@ void EpubReaderActivity::renderStatusBar() const {
       title = tocItem.title;
       titleWidth = renderer.getTextWidth(SMALL_FONT_ID, title.c_str());
       while (titleWidth > availableTextWidth && title.length() > 11) {
-      title = title.substr(0, title.length() - 8) + "...";
+        title.replace(title.length() - 8, 8, "...");
         titleWidth = renderer.getTextWidth(SMALL_FONT_ID, title.c_str());
       }
     }
 
     renderer.drawText(SMALL_FONT_ID, titleMarginLeft + (availableTextWidth - titleWidth) / 2, textY, title.c_str());
+  }
 }

src/activities/reader/EpubReaderActivity.h

@@ -5,19 +5,19 @@
 #include <freertos/semphr.h>
 #include <freertos/task.h>
 
-#include "../Activity.h"
+#include "activities/ActivityWithSubactivity.h"
 
-class EpubReaderActivity final : public Activity {
+class EpubReaderActivity final : public ActivityWithSubactivity {
   std::shared_ptr<Epub> epub;
   std::unique_ptr<Section> section = nullptr;
   TaskHandle_t displayTaskHandle = nullptr;
   SemaphoreHandle_t renderingMutex = nullptr;
-  std::unique_ptr<Activity> subAcitivity = nullptr;
   int currentSpineIndex = 0;
   int nextPageNumber = 0;
   int pagesUntilFullRefresh = 0;
   bool updateRequired = false;
   const std::function<void()> onGoBack;
+  const std::function<void()> onGoHome;
 
   static void taskTrampoline(void* param);
   [[noreturn]] void displayTaskLoop();
@@ -27,8 +27,11 @@ class EpubReaderActivity final : public Activity {
 
  public:
   explicit EpubReaderActivity(GfxRenderer& renderer, InputManager& inputManager, std::unique_ptr<Epub> epub,
-                              const std::function<void()>& onGoBack)
+                              const std::function<void()>& onGoBack, const std::function<void()>& onGoHome)
-      : Activity(renderer, inputManager), epub(std::move(epub)), onGoBack(onGoBack) {}
+      : ActivityWithSubactivity("EpubReader", renderer, inputManager),
+        epub(std::move(epub)),
+        onGoBack(onGoBack),
+        onGoHome(onGoHome) {}
   void onEnter() override;
   void onExit() override;
   void loop() override;

src/activities/reader/EpubReaderChapterSelectionActivity.cpp

@@ -1,12 +1,15 @@
 #include "EpubReaderChapterSelectionActivity.h"
 
 #include <GfxRenderer.h>
+#include <InputManager.h>
 #include <SD.h>
 
 #include "config.h"
 
+namespace {
 // Time threshold for treating a long press as a page-up/page-down
 constexpr int SKIP_PAGE_MS = 700;
+}  // namespace
 
 int EpubReaderChapterSelectionActivity::getPageItems() const {
   // Layout constants used in renderScreen
@@ -30,6 +33,8 @@ void EpubReaderChapterSelectionActivity::taskTrampoline(void* param) {
 }
 
 void EpubReaderChapterSelectionActivity::onEnter() {
+  Activity::onEnter();
+
   if (!epub) {
     return;
   }
@@ -40,7 +45,7 @@ void EpubReaderChapterSelectionActivity::onEnter() {
   // Trigger first update
   updateRequired = true;
   xTaskCreate(&EpubReaderChapterSelectionActivity::taskTrampoline, "EpubReaderChapterSelectionActivityTask",
-              2048,               // Stack size
+              4096,               // Stack size
               this,               // Parameters
               1,                  // Priority
               &displayTaskHandle  // Task handle
@@ -48,6 +53,8 @@ void EpubReaderChapterSelectionActivity::onEnter() {
 }
 
 void EpubReaderChapterSelectionActivity::onExit() {
+  Activity::onExit();
+
   // Wait until not rendering to delete task to avoid killing mid-instruction to EPD
   xSemaphoreTake(renderingMutex, portMAX_DELAY);
   if (displayTaskHandle) {
@@ -67,9 +74,9 @@ void EpubReaderChapterSelectionActivity::loop() {
   const bool skipPage = inputManager.getHeldTime() > SKIP_PAGE_MS;
   const int pageItems = getPageItems();
 
-  if (inputManager.wasPressed(InputManager::BTN_CONFIRM)) {
+  if (inputManager.wasReleased(InputManager::BTN_CONFIRM)) {
     onSelectSpineIndex(selectorIndex);
-  } else if (inputManager.wasPressed(InputManager::BTN_BACK)) {
+  } else if (inputManager.wasReleased(InputManager::BTN_BACK)) {
     onGoBack();
   } else if (prevReleased) {
     if (skipPage) {

src/activities/reader/EpubReaderChapterSelectionActivity.h

@@ -31,7 +31,7 @@ class EpubReaderChapterSelectionActivity final : public Activity {
                                               const std::shared_ptr<Epub>& epub, const int currentSpineIndex,
                                               const std::function<void()>& onGoBack,
                                               const std::function<void(int newSpineIndex)>& onSelectSpineIndex)
-      : Activity(renderer, inputManager),
+      : Activity("EpubReaderChapterSelection", renderer, inputManager),
         epub(epub),
         currentSpineIndex(currentSpineIndex),
         onGoBack(onGoBack),

src/activities/reader/FileSelectionActivity.cpp

@@ -1,10 +1,17 @@
 #include "FileSelectionActivity.h"
 
 #include <GfxRenderer.h>
+#include <InputManager.h>
 #include <SD.h>
 
 #include "config.h"
 
+namespace {
+constexpr int PAGE_ITEMS = 23;
+constexpr int SKIP_PAGE_MS = 700;
+constexpr unsigned long GO_HOME_MS = 1000;
+}  // namespace
+
 void sortFileList(std::vector<std::string>& strs) {
   std::sort(begin(strs), end(strs), [](const std::string& str1, const std::string& str2) {
     if (str1.back() == '/' && str2.back() != '/') return true;
@@ -43,9 +50,11 @@ void FileSelectionActivity::loadFiles() {
 }
 
 void FileSelectionActivity::onEnter() {
+  Activity::onEnter();
+
   renderingMutex = xSemaphoreCreateMutex();
 
-  basepath = "/";
+  // basepath is set via constructor parameter (defaults to "/" if not specified)
   loadFiles();
   selectorIndex = 0;
 
@@ -61,6 +70,8 @@ void FileSelectionActivity::onEnter() {
 }
 
 void FileSelectionActivity::onExit() {
+  Activity::onExit();
+
   // Wait until not rendering to delete task to avoid killing mid-instruction to EPD
   xSemaphoreTake(renderingMutex, portMAX_DELAY);
   if (displayTaskHandle) {
@@ -73,10 +84,22 @@ void FileSelectionActivity::onExit() {
 }
 
 void FileSelectionActivity::loop() {
-  const bool prevPressed =
+  // Long press BACK (1s+) goes to root folder
-      inputManager.wasPressed(InputManager::BTN_UP) || inputManager.wasPressed(InputManager::BTN_LEFT);
+  if (inputManager.isPressed(InputManager::BTN_BACK) && inputManager.getHeldTime() >= GO_HOME_MS) {
-  const bool nextPressed =
+    if (basepath != "/") {
-      inputManager.wasPressed(InputManager::BTN_DOWN) || inputManager.wasPressed(InputManager::BTN_RIGHT);
+      basepath = "/";
+      loadFiles();
+      updateRequired = true;
+    }
+    return;
+  }
+
+  const bool prevReleased =
+      inputManager.wasReleased(InputManager::BTN_UP) || inputManager.wasReleased(InputManager::BTN_LEFT);
+  const bool nextReleased =
+      inputManager.wasReleased(InputManager::BTN_DOWN) || inputManager.wasReleased(InputManager::BTN_RIGHT);
+
+  const bool skipPage = inputManager.getHeldTime() > SKIP_PAGE_MS;
 
   if (inputManager.wasPressed(InputManager::BTN_CONFIRM)) {
     if (files.empty()) {
@@ -91,21 +114,31 @@ void FileSelectionActivity::loop() {
     } else {
       onSelect(basepath + files[selectorIndex]);
     }
-  } else if (inputManager.wasPressed(InputManager::BTN_BACK)) {
+  } else if (inputManager.wasReleased(InputManager::BTN_BACK)) {
+    // Short press: go up one directory, or go home if at root
+    if (inputManager.getHeldTime() < GO_HOME_MS) {
       if (basepath != "/") {
-      basepath = basepath.substr(0, basepath.rfind('/'));
+        basepath.replace(basepath.find_last_of('/'), std::string::npos, "");
         if (basepath.empty()) basepath = "/";
         loadFiles();
         updateRequired = true;
       } else {
-      // At root level, go back home
         onGoHome();
       }
-  } else if (prevPressed) {
+    }
+  } else if (prevReleased) {
+    if (skipPage) {
+      selectorIndex = ((selectorIndex / PAGE_ITEMS - 1) * PAGE_ITEMS + files.size()) % files.size();
+    } else {
       selectorIndex = (selectorIndex + files.size() - 1) % files.size();
+    }
     updateRequired = true;
-  } else if (nextPressed) {
+  } else if (nextReleased) {
+    if (skipPage) {
+      selectorIndex = ((selectorIndex / PAGE_ITEMS + 1) * PAGE_ITEMS) % files.size();
+    } else {
       selectorIndex = (selectorIndex + 1) % files.size();
+    }
     updateRequired = true;
   }
 }
@@ -126,21 +159,27 @@ void FileSelectionActivity::render() const {
   renderer.clearScreen();
 
   const auto pageWidth = GfxRenderer::getScreenWidth();
-  renderer.drawCenteredText(READER_FONT_ID, 10, "CrossPoint Reader", true, BOLD);
+  renderer.drawCenteredText(READER_FONT_ID, 10, "Books", true, BOLD);
 
   // Help text
-  renderer.drawText(SMALL_FONT_ID, 20, GfxRenderer::getScreenHeight() - 30, "Press BACK for Home");
+  renderer.drawButtonHints(UI_FONT_ID, "« Home", "Open", "", "");
 
   if (files.empty()) {
     renderer.drawText(UI_FONT_ID, 20, 60, "No EPUBs found");
-  } else {
+    renderer.displayBuffer();
-    // Draw selection
+    return;
-    renderer.fillRect(0, 60 + selectorIndex * 30 + 2, pageWidth - 1, 30);
-
-    for (size_t i = 0; i < files.size(); i++) {
-      const auto file = files[i];
-      renderer.drawText(UI_FONT_ID, 20, 60 + i * 30, file.c_str(), i != selectorIndex);
   }
+
+  const auto pageStartIndex = selectorIndex / PAGE_ITEMS * PAGE_ITEMS;
+  renderer.fillRect(0, 60 + (selectorIndex % PAGE_ITEMS) * 30 + 2, pageWidth - 1, 30);
+  for (int i = pageStartIndex; i < files.size() && i < pageStartIndex + PAGE_ITEMS; i++) {
+    auto item = files[i];
+    int itemWidth = renderer.getTextWidth(UI_FONT_ID, item.c_str());
+    while (itemWidth > renderer.getScreenWidth() - 40 && item.length() > 8) {
+      item.replace(item.length() - 5, 5, "...");
+      itemWidth = renderer.getTextWidth(UI_FONT_ID, item.c_str());
+    }
+    renderer.drawText(UI_FONT_ID, 20, 60 + (i % PAGE_ITEMS) * 30, item.c_str(), i != selectorIndex);
   }
 
   renderer.displayBuffer();

src/activities/reader/FileSelectionActivity.h

@@ -27,8 +27,11 @@ class FileSelectionActivity final : public Activity {
  public:
   explicit FileSelectionActivity(GfxRenderer& renderer, InputManager& inputManager,
                                  const std::function<void(const std::string&)>& onSelect,
-                                 const std::function<void()>& onGoHome)
+                                 const std::function<void()>& onGoHome, std::string initialPath = "/")
-      : Activity(renderer, inputManager), onSelect(onSelect), onGoHome(onGoHome) {}
+      : Activity("FileSelection", renderer, inputManager),
+        basepath(initialPath.empty() ? "/" : std::move(initialPath)),
+        onSelect(onSelect),
+        onGoHome(onGoHome) {}
   void onEnter() override;
   void onExit() override;
   void loop() override;

src/activities/reader/ReaderActivity.cpp

@@ -2,12 +2,19 @@
 
 #include <SD.h>
 
-#include "CrossPointState.h"
 #include "Epub.h"
 #include "EpubReaderActivity.h"
 #include "FileSelectionActivity.h"
 #include "activities/util/FullScreenMessageActivity.h"
 
+std::string ReaderActivity::extractFolderPath(const std::string& filePath) {
+  const auto lastSlash = filePath.find_last_of('/');
+  if (lastSlash == std::string::npos || lastSlash == 0) {
+    return "/";
+  }
+  return filePath.substr(0, lastSlash);
+}
+
 std::unique_ptr<Epub> ReaderActivity::loadEpub(const std::string& path) {
   if (!SD.exists(path.c_str())) {
     Serial.printf("[%lu] [   ] File does not exist: %s\n", millis(), path.c_str());
@@ -24,13 +31,12 @@ std::unique_ptr<Epub> ReaderActivity::loadEpub(const std::string& path) {
 }
 
 void ReaderActivity::onSelectEpubFile(const std::string& path) {
+  currentEpubPath = path;  // Track current book path
   exitActivity();
   enterNewActivity(new FullScreenMessageActivity(renderer, inputManager, "Loading..."));
 
   auto epub = loadEpub(path);
   if (epub) {
-    APP_STATE.openEpubPath = path;
-    APP_STATE.saveToFile();
     onGoToEpubReader(std::move(epub));
   } else {
     exitActivity();
@@ -41,23 +47,32 @@ void ReaderActivity::onSelectEpubFile(const std::string& path) {
   }
 }
 
-void ReaderActivity::onGoToFileSelection() {
+void ReaderActivity::onGoToFileSelection(const std::string& fromEpubPath) {
   exitActivity();
+  // If coming from a book, start in that book's folder; otherwise start from root
+  const auto initialPath = fromEpubPath.empty() ? "/" : extractFolderPath(fromEpubPath);
   enterNewActivity(new FileSelectionActivity(
-      renderer, inputManager, [this](const std::string& path) { onSelectEpubFile(path); }, onGoBack));
+      renderer, inputManager, [this](const std::string& path) { onSelectEpubFile(path); }, onGoBack, initialPath));
 }
 
 void ReaderActivity::onGoToEpubReader(std::unique_ptr<Epub> epub) {
+  const auto epubPath = epub->getPath();
+  currentEpubPath = epubPath;
   exitActivity();
-  enterNewActivity(new EpubReaderActivity(renderer, inputManager, std::move(epub), [this] { onGoToFileSelection(); }));
+  enterNewActivity(new EpubReaderActivity(
+      renderer, inputManager, std::move(epub), [this, epubPath] { onGoToFileSelection(epubPath); },
+      [this] { onGoBack(); }));
 }
 
 void ReaderActivity::onEnter() {
+  ActivityWithSubactivity::onEnter();
+
   if (initialEpubPath.empty()) {
-    onGoToFileSelection();
+    onGoToFileSelection();  // Start from root when entering via Browse
     return;
   }
 
+  currentEpubPath = initialEpubPath;
   auto epub = loadEpub(initialEpubPath);
   if (!epub) {
     onGoBack();

src/activities/reader/ReaderActivity.h

@@ -7,17 +7,19 @@ class Epub;
 
 class ReaderActivity final : public ActivityWithSubactivity {
   std::string initialEpubPath;
+  std::string currentEpubPath;  // Track current book path for navigation
   const std::function<void()> onGoBack;
   static std::unique_ptr<Epub> loadEpub(const std::string& path);
 
+  static std::string extractFolderPath(const std::string& filePath);
   void onSelectEpubFile(const std::string& path);
-  void onGoToFileSelection();
+  void onGoToFileSelection(const std::string& fromEpubPath = "");
   void onGoToEpubReader(std::unique_ptr<Epub> epub);
 
  public:
   explicit ReaderActivity(GfxRenderer& renderer, InputManager& inputManager, std::string initialEpubPath,
                           const std::function<void()>& onGoBack)
-      : ActivityWithSubactivity(renderer, inputManager),
+      : ActivityWithSubactivity("Reader", renderer, inputManager),
         initialEpubPath(std::move(initialEpubPath)),
         onGoBack(onGoBack) {}
   void onEnter() override;

src/activities/settings/OtaUpdateActivity.cpp

@@ -0,0 +1,242 @@
+#include "OtaUpdateActivity.h"
+
+#include <GfxRenderer.h>
+#include <InputManager.h>
+#include <WiFi.h>
+
+#include "activities/network/WifiSelectionActivity.h"
+#include "config.h"
+#include "network/OtaUpdater.h"
+
+void OtaUpdateActivity::taskTrampoline(void* param) {
+  auto* self = static_cast<OtaUpdateActivity*>(param);
+  self->displayTaskLoop();
+}
+
+void OtaUpdateActivity::onWifiSelectionComplete(const bool success) {
+  exitActivity();
+
+  if (!success) {
+    Serial.printf("[%lu] [OTA] WiFi connection failed, exiting\n", millis());
+    goBack();
+    return;
+  }
+
+  Serial.printf("[%lu] [OTA] WiFi connected, checking for update\n", millis());
+
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
+  state = CHECKING_FOR_UPDATE;
+  xSemaphoreGive(renderingMutex);
+  updateRequired = true;
+  vTaskDelay(10 / portTICK_PERIOD_MS);
+  const auto res = updater.checkForUpdate();
+  if (res != OtaUpdater::OK) {
+    Serial.printf("[%lu] [OTA] Update check failed: %d\n", millis(), res);
+    xSemaphoreTake(renderingMutex, portMAX_DELAY);
+    state = FAILED;
+    xSemaphoreGive(renderingMutex);
+    updateRequired = true;
+    return;
+  }
+
+  if (!updater.isUpdateNewer()) {
+    Serial.printf("[%lu] [OTA] No new update available\n", millis());
+    xSemaphoreTake(renderingMutex, portMAX_DELAY);
+    state = NO_UPDATE;
+    xSemaphoreGive(renderingMutex);
+    updateRequired = true;
+    return;
+  }
+
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
+  state = WAITING_CONFIRMATION;
+  xSemaphoreGive(renderingMutex);
+  updateRequired = true;
+}
+
+void OtaUpdateActivity::onEnter() {
+  ActivityWithSubactivity::onEnter();
+
+  renderingMutex = xSemaphoreCreateMutex();
+
+  xTaskCreate(&OtaUpdateActivity::taskTrampoline, "OtaUpdateActivityTask",
+              2048,               // Stack size
+              this,               // Parameters
+              1,                  // Priority
+              &displayTaskHandle  // Task handle
+  );
+
+  // Turn on WiFi immediately
+  Serial.printf("[%lu] [OTA] Turning on WiFi...\n", millis());
+  WiFi.mode(WIFI_STA);
+
+  // Launch WiFi selection subactivity
+  Serial.printf("[%lu] [OTA] Launching WifiSelectionActivity...\n", millis());
+  enterNewActivity(new WifiSelectionActivity(renderer, inputManager,
+                                             [this](const bool connected) { onWifiSelectionComplete(connected); }));
+}
+
+void OtaUpdateActivity::onExit() {
+  ActivityWithSubactivity::onExit();
+
+  // Turn off wifi
+  WiFi.disconnect(false);  // false = don't erase credentials, send disconnect frame
+  delay(100);              // Allow disconnect frame to be sent
+  WiFi.mode(WIFI_OFF);
+  delay(100);  // Allow WiFi hardware to fully power down
+
+  // Wait until not rendering to delete task to avoid killing mid-instruction to EPD
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
+  if (displayTaskHandle) {
+    vTaskDelete(displayTaskHandle);
+    displayTaskHandle = nullptr;
+  }
+  vSemaphoreDelete(renderingMutex);
+  renderingMutex = nullptr;
+}
+
+void OtaUpdateActivity::displayTaskLoop() {
+  while (true) {
+    if (updateRequired) {
+      updateRequired = false;
+      xSemaphoreTake(renderingMutex, portMAX_DELAY);
+      render();
+      xSemaphoreGive(renderingMutex);
+    }
+    vTaskDelay(10 / portTICK_PERIOD_MS);
+  }
+}
+
+void OtaUpdateActivity::render() {
+  if (subActivity) {
+    // Subactivity handles its own rendering
+    return;
+  }
+
+  float updaterProgress = 0;
+  if (state == UPDATE_IN_PROGRESS) {
+    Serial.printf("[%lu] [OTA] Update progress: %d / %d\n", millis(), updater.processedSize, updater.totalSize);
+    updaterProgress = static_cast<float>(updater.processedSize) / static_cast<float>(updater.totalSize);
+    // Only update every 2% at the most
+    if (static_cast<int>(updaterProgress * 50) == lastUpdaterPercentage / 2) {
+      return;
+    }
+    lastUpdaterPercentage = static_cast<int>(updaterProgress * 100);
+  }
+
+  const auto pageHeight = renderer.getScreenHeight();
+  const auto pageWidth = renderer.getScreenWidth();
+
+  renderer.clearScreen();
+  renderer.drawCenteredText(READER_FONT_ID, 10, "Update", true, BOLD);
+
+  if (state == CHECKING_FOR_UPDATE) {
+    renderer.drawCenteredText(UI_FONT_ID, 300, "Checking for update...", true, BOLD);
+    renderer.displayBuffer();
+    return;
+  }
+
+  if (state == WAITING_CONFIRMATION) {
+    renderer.drawCenteredText(UI_FONT_ID, 200, "New update available!", true, BOLD);
+    renderer.drawText(UI_FONT_ID, 20, 250, "Current Version: " CROSSPOINT_VERSION);
+    renderer.drawText(UI_FONT_ID, 20, 270, ("New Version: " + updater.getLatestVersion()).c_str());
+
+    renderer.drawRect(25, pageHeight - 40, 106, 40);
+    renderer.drawText(UI_FONT_ID, 25 + (105 - renderer.getTextWidth(UI_FONT_ID, "Cancel")) / 2, pageHeight - 35,
+                      "Cancel");
+
+    renderer.drawRect(130, pageHeight - 40, 106, 40);
+    renderer.drawText(UI_FONT_ID, 130 + (105 - renderer.getTextWidth(UI_FONT_ID, "Update")) / 2, pageHeight - 35,
+                      "Update");
+    renderer.displayBuffer();
+    return;
+  }
+
+  if (state == UPDATE_IN_PROGRESS) {
+    renderer.drawCenteredText(UI_FONT_ID, 310, "Updating...", true, BOLD);
+    renderer.drawRect(20, 350, pageWidth - 40, 50);
+    renderer.fillRect(24, 354, static_cast<int>(updaterProgress * static_cast<float>(pageWidth - 44)), 42);
+    renderer.drawCenteredText(UI_FONT_ID, 420, (std::to_string(static_cast<int>(updaterProgress * 100)) + "%").c_str());
+    renderer.drawCenteredText(
+        UI_FONT_ID, 440, (std::to_string(updater.processedSize) + " / " + std::to_string(updater.totalSize)).c_str());
+    renderer.displayBuffer();
+    return;
+  }
+
+  if (state == NO_UPDATE) {
+    renderer.drawCenteredText(UI_FONT_ID, 300, "No update available", true, BOLD);
+    renderer.displayBuffer();
+    return;
+  }
+
+  if (state == FAILED) {
+    renderer.drawCenteredText(UI_FONT_ID, 300, "Update failed", true, BOLD);
+    renderer.displayBuffer();
+    return;
+  }
+
+  if (state == FINISHED) {
+    renderer.drawCenteredText(UI_FONT_ID, 300, "Update complete", true, BOLD);
+    renderer.drawCenteredText(UI_FONT_ID, 350, "Press and hold power button to turn back on");
+    renderer.displayBuffer();
+    state = SHUTTING_DOWN;
+    return;
+  }
+}
+
+void OtaUpdateActivity::loop() {
+  if (subActivity) {
+    subActivity->loop();
+    return;
+  }
+
+  if (state == WAITING_CONFIRMATION) {
+    if (inputManager.wasPressed(InputManager::BTN_CONFIRM)) {
+      Serial.printf("[%lu] [OTA] New update available, starting download...\n", millis());
+      xSemaphoreTake(renderingMutex, portMAX_DELAY);
+      state = UPDATE_IN_PROGRESS;
+      xSemaphoreGive(renderingMutex);
+      updateRequired = true;
+      vTaskDelay(10 / portTICK_PERIOD_MS);
+      const auto res = updater.installUpdate([this](const size_t, const size_t) { updateRequired = true; });
+
+      if (res != OtaUpdater::OK) {
+        Serial.printf("[%lu] [OTA] Update failed: %d\n", millis(), res);
+        xSemaphoreTake(renderingMutex, portMAX_DELAY);
+        state = FAILED;
+        xSemaphoreGive(renderingMutex);
+        updateRequired = true;
+        return;
+      }
+
+      xSemaphoreTake(renderingMutex, portMAX_DELAY);
+      state = FINISHED;
+      xSemaphoreGive(renderingMutex);
+      updateRequired = true;
+    }
+
+    if (inputManager.wasPressed(InputManager::BTN_BACK)) {
+      goBack();
+    }
+
+    return;
+  }
+
+  if (state == FAILED) {
+    if (inputManager.wasPressed(InputManager::BTN_BACK)) {
+      goBack();
+    }
+    return;
+  }
+
+  if (state == NO_UPDATE) {
+    if (inputManager.wasPressed(InputManager::BTN_BACK)) {
+      goBack();
+    }
+    return;
+  }
+
+  if (state == SHUTTING_DOWN) {
+    ESP.restart();
+  }
+}

src/activities/settings/OtaUpdateActivity.h

@@ -0,0 +1,43 @@
+#pragma once
+#include <freertos/FreeRTOS.h>
+#include <freertos/semphr.h>
+#include <freertos/task.h>
+
+#include "activities/ActivityWithSubactivity.h"
+#include "network/OtaUpdater.h"
+
+class OtaUpdateActivity : public ActivityWithSubactivity {
+  enum State {
+    WIFI_SELECTION,
+    CHECKING_FOR_UPDATE,
+    WAITING_CONFIRMATION,
+    UPDATE_IN_PROGRESS,
+    NO_UPDATE,
+    FAILED,
+    FINISHED,
+    SHUTTING_DOWN
+  };
+
+  // Can't initialize this to 0 or the first render doesn't happen
+  static constexpr unsigned int UNINITIALIZED_PERCENTAGE = 111;
+
+  TaskHandle_t displayTaskHandle = nullptr;
+  SemaphoreHandle_t renderingMutex = nullptr;
+  bool updateRequired = false;
+  const std::function<void()> goBack;
+  State state = WIFI_SELECTION;
+  unsigned int lastUpdaterPercentage = UNINITIALIZED_PERCENTAGE;
+  OtaUpdater updater;
+
+  void onWifiSelectionComplete(bool success);
+  static void taskTrampoline(void* param);
+  [[noreturn]] void displayTaskLoop();
+  void render();
+
+ public:
+  explicit OtaUpdateActivity(GfxRenderer& renderer, InputManager& inputManager, const std::function<void()>& goBack)
+      : ActivityWithSubactivity("OtaUpdate", renderer, inputManager), goBack(goBack), updater() {}
+  void onEnter() override;
+  void onExit() override;
+  void loop() override;
+};

src/activities/settings/SettingsActivity.cpp

@@ -1,18 +1,26 @@
 #include "SettingsActivity.h"
 
 #include <GfxRenderer.h>
+#include <InputManager.h>
 
 #include "CrossPointSettings.h"
+#include "OtaUpdateActivity.h"
 #include "config.h"
 
 // Define the static settings list
-
+namespace {
-const SettingInfo SettingsActivity::settingsList[settingsCount] = {
+constexpr int settingsCount = 7;
-    {"White Sleep Screen", SettingType::TOGGLE, &CrossPointSettings::whiteSleepScreen},
+const SettingInfo settingsList[settingsCount] = {
-    {"Extra Paragraph Spacing", SettingType::TOGGLE, &CrossPointSettings::extraParagraphSpacing},
+    // Should match with SLEEP_SCREEN_MODE
-    {"Short Power Button Click", SettingType::TOGGLE, &CrossPointSettings::shortPwrBtn},
+    {"Sleep Screen", SettingType::ENUM, &CrossPointSettings::sleepScreen, {"Dark", "Light", "Custom", "Cover"}},
+    {"Status Bar", SettingType::ENUM, &CrossPointSettings::statusBar, {"None", "No Progress", "Full"}},
+    {"Extra Paragraph Spacing", SettingType::TOGGLE, &CrossPointSettings::extraParagraphSpacing, {}},
+    {"Short Power Button Click", SettingType::TOGGLE, &CrossPointSettings::shortPwrBtn, {}},
     {"Landscape Reading", SettingType::TOGGLE, &CrossPointSettings::landscapeReading},
-    {"Flip Landscape (swap top/bottom)", SettingType::TOGGLE, &CrossPointSettings::landscapeFlipped}};
+    {"Flip Landscape (swap top/bottom)", SettingType::TOGGLE, &CrossPointSettings::landscapeFlipped},
+    {"Check for updates", SettingType::ACTION, nullptr, {}},
+};
+}  // namespace
 
 void SettingsActivity::taskTrampoline(void* param) {
   auto* self = static_cast<SettingsActivity*>(param);
@@ -20,6 +28,8 @@ void SettingsActivity::taskTrampoline(void* param) {
 }
 
 void SettingsActivity::onEnter() {
+  Activity::onEnter();
+
   renderingMutex = xSemaphoreCreateMutex();
 
   // Reset selection to first item
@@ -37,6 +47,8 @@ void SettingsActivity::onEnter() {
 }
 
 void SettingsActivity::onExit() {
+  ActivityWithSubactivity::onExit();
+
   // Wait until not rendering to delete task to avoid killing mid-instruction to EPD
   xSemaphoreTake(renderingMutex, portMAX_DELAY);
   if (displayTaskHandle) {
@@ -48,6 +60,11 @@ void SettingsActivity::onExit() {
 }
 
 void SettingsActivity::loop() {
+  if (subActivity) {
+    subActivity->loop();
+    return;
+  }
+
   // Handle actions with early return
   if (inputManager.wasPressed(InputManager::BTN_CONFIRM)) {
     toggleCurrentSetting();
@@ -83,22 +100,35 @@ void SettingsActivity::toggleCurrentSetting() {
 
   const auto& setting = settingsList[selectedSettingIndex];
 
+  if (setting.type == SettingType::TOGGLE && setting.valuePtr != nullptr) {
+    // Toggle the boolean value using the member pointer
+    const bool currentValue = SETTINGS.*(setting.valuePtr);
+    SETTINGS.*(setting.valuePtr) = !currentValue;
+  } else if (setting.type == SettingType::ENUM && setting.valuePtr != nullptr) {
+    const uint8_t currentValue = SETTINGS.*(setting.valuePtr);
+    SETTINGS.*(setting.valuePtr) = (currentValue + 1) % static_cast<uint8_t>(setting.enumValues.size());
+  } else if (setting.type == SettingType::ACTION) {
+    if (std::string(setting.name) == "Check for updates") {
+      xSemaphoreTake(renderingMutex, portMAX_DELAY);
+      exitActivity();
+      enterNewActivity(new OtaUpdateActivity(renderer, inputManager, [this] {
+        exitActivity();
+        updateRequired = true;
+      }));
+      xSemaphoreGive(renderingMutex);
+    }
+  } else {
     // Only toggle if it's a toggle type and has a value pointer
-  if (setting.type != SettingType::TOGGLE || setting.valuePtr == nullptr) {
     return;
   }
 
-  // Toggle the boolean value using the member pointer
-  bool currentValue = SETTINGS.*(setting.valuePtr);
-  SETTINGS.*(setting.valuePtr) = !currentValue;
-
   // Save settings when they change
   SETTINGS.saveToFile();
 }
 
 void SettingsActivity::displayTaskLoop() {
   while (true) {
-    if (updateRequired) {
+    if (updateRequired && !subActivity) {
       updateRequired = false;
       xSemaphoreTake(renderingMutex, portMAX_DELAY);
       render();
@@ -131,13 +161,20 @@ void SettingsActivity::render() const {
 
     // Draw value based on setting type
     if (settingsList[i].type == SettingType::TOGGLE && settingsList[i].valuePtr != nullptr) {
-      bool value = SETTINGS.*(settingsList[i].valuePtr);
+      const bool value = SETTINGS.*(settingsList[i].valuePtr);
       renderer.drawText(UI_FONT_ID, pageWidth - 80, settingY, value ? "ON" : "OFF");
+    } else if (settingsList[i].type == SettingType::ENUM && settingsList[i].valuePtr != nullptr) {
+      const uint8_t value = SETTINGS.*(settingsList[i].valuePtr);
+      auto valueText = settingsList[i].enumValues[value];
+      const auto width = renderer.getTextWidth(UI_FONT_ID, valueText.c_str());
+      renderer.drawText(UI_FONT_ID, pageWidth - 50 - width, settingY, valueText.c_str());
     }
   }
 
   // Draw help text
-  renderer.drawText(SMALL_FONT_ID, 20, pageHeight - 30, "Press OK to toggle, BACK to save & exit");
+  renderer.drawButtonHints(UI_FONT_ID, "« Save", "Toggle", "", "");
+  renderer.drawText(SMALL_FONT_ID, pageWidth - 20 - renderer.getTextWidth(SMALL_FONT_ID, CROSSPOINT_VERSION),
+                    pageHeight - 30, CROSSPOINT_VERSION);
 
   // Always use standard refresh for settings screen
   renderer.displayBuffer();

src/activities/settings/SettingsActivity.h

@@ -3,35 +3,31 @@
 #include <freertos/semphr.h>
 #include <freertos/task.h>
 
-#include <cstdint>
 #include <functional>
 #include <string>
 #include <vector>
 
-#include "../Activity.h"
+#include "activities/ActivityWithSubactivity.h"
 
 class CrossPointSettings;
 
-enum class SettingType { TOGGLE };
+enum class SettingType { TOGGLE, ENUM, ACTION };
 
 // Structure to hold setting information
 struct SettingInfo {
   const char* name;                        // Display name of the setting
   SettingType type;                        // Type of setting
-  uint8_t CrossPointSettings::* valuePtr;  // Pointer to member in CrossPointSettings (for TOGGLE)
+  uint8_t CrossPointSettings::* valuePtr;  // Pointer to member in CrossPointSettings (for TOGGLE/ENUM)
+  std::vector<std::string> enumValues;
 };
 
-class SettingsActivity final : public Activity {
+class SettingsActivity final : public ActivityWithSubactivity {
   TaskHandle_t displayTaskHandle = nullptr;
   SemaphoreHandle_t renderingMutex = nullptr;
   bool updateRequired = false;
   int selectedSettingIndex = 0;  // Currently selected setting
   const std::function<void()> onGoHome;
 
-  // Static settings list
-  static constexpr int settingsCount = 5;  // Number of settings
-  static const SettingInfo settingsList[settingsCount];
-
   static void taskTrampoline(void* param);
   [[noreturn]] void displayTaskLoop();
   void render() const;
@@ -39,7 +35,7 @@ class SettingsActivity final : public Activity {
 
  public:
   explicit SettingsActivity(GfxRenderer& renderer, InputManager& inputManager, const std::function<void()>& onGoHome)
-      : Activity(renderer, inputManager), onGoHome(onGoHome) {}
+      : ActivityWithSubactivity("Settings", renderer, inputManager), onGoHome(onGoHome) {}
   void onEnter() override;
   void onExit() override;
   void loop() override;

src/activities/util/FullScreenMessageActivity.cpp

@@ -5,6 +5,8 @@
 #include "config.h"
 
 void FullScreenMessageActivity::onEnter() {
+  Activity::onEnter();
+
   const auto height = renderer.getLineHeight(UI_FONT_ID);
   const auto top = (GfxRenderer::getScreenHeight() - height) / 2;
 

src/activities/util/FullScreenMessageActivity.h

@@ -16,6 +16,9 @@ class FullScreenMessageActivity final : public Activity {
   explicit FullScreenMessageActivity(GfxRenderer& renderer, InputManager& inputManager, std::string text,
                                      const EpdFontStyle style = REGULAR,
                                      const EInkDisplay::RefreshMode refreshMode = EInkDisplay::FAST_REFRESH)
-      : Activity(renderer, inputManager), text(std::move(text)), style(style), refreshMode(refreshMode) {}
+      : Activity("FullScreenMessage", renderer, inputManager),
+        text(std::move(text)),
+        style(style),
+        refreshMode(refreshMode) {}
   void onEnter() override;
 };

src/activities/util/KeyboardEntryActivity.cpp

@@ -10,48 +10,55 @@ const char* const KeyboardEntryActivity::keyboard[NUM_ROWS] = {
 
 // Keyboard layouts - uppercase/symbols
 const char* const KeyboardEntryActivity::keyboardShift[NUM_ROWS] = {"~!@#$%^&*()_+", "QWERTYUIOP{}|", "ASDFGHJKL:\"",
-                                                                    "ZXCVBNM<>?", "^  _____<OK"};
+                                                                    "ZXCVBNM<>?", "SPECIAL ROW"};
 
-KeyboardEntryActivity::KeyboardEntryActivity(GfxRenderer& renderer, InputManager& inputManager,
+void KeyboardEntryActivity::taskTrampoline(void* param) {
-                                             const std::string& title, const std::string& initialText, size_t maxLength,
+  auto* self = static_cast<KeyboardEntryActivity*>(param);
-                                             bool isPassword)
+  self->displayTaskLoop();
-    : Activity(renderer, inputManager), title(title), text(initialText), maxLength(maxLength), isPassword(isPassword) {}
-
-void KeyboardEntryActivity::setText(const std::string& newText) {
-  text = newText;
-  if (maxLength > 0 && text.length() > maxLength) {
-    text = text.substr(0, maxLength);
-  }
 }
 
-void KeyboardEntryActivity::reset(const std::string& newTitle, const std::string& newInitialText) {
+void KeyboardEntryActivity::displayTaskLoop() {
-  if (!newTitle.empty()) {
+  while (true) {
-    title = newTitle;
+    if (updateRequired) {
+      updateRequired = false;
+      xSemaphoreTake(renderingMutex, portMAX_DELAY);
+      render();
+      xSemaphoreGive(renderingMutex);
+    }
+    vTaskDelay(10 / portTICK_PERIOD_MS);
   }
-  text = newInitialText;
-  selectedRow = 0;
-  selectedCol = 0;
-  shiftActive = false;
-  complete = false;
-  cancelled = false;
 }
 
 void KeyboardEntryActivity::onEnter() {
-  // Reset state when entering the activity
+  Activity::onEnter();
-  complete = false;
+
-  cancelled = false;
+  renderingMutex = xSemaphoreCreateMutex();
+
+  // Trigger first update
+  updateRequired = true;
+
+  xTaskCreate(&KeyboardEntryActivity::taskTrampoline, "KeyboardEntryActivity",
+              2048,               // Stack size
+              this,               // Parameters
+              1,                  // Priority
+              &displayTaskHandle  // Task handle
+  );
 }
 
 void KeyboardEntryActivity::onExit() {
-  // Clean up if needed
+  Activity::onExit();
+
+  // Wait until not rendering to delete task to avoid killing mid-instruction to EPD
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
+  if (displayTaskHandle) {
+    vTaskDelete(displayTaskHandle);
+    displayTaskHandle = nullptr;
+  }
+  vSemaphoreDelete(renderingMutex);
+  renderingMutex = nullptr;
 }
 
-void KeyboardEntryActivity::loop() {
+int KeyboardEntryActivity::getRowLength(const int row) const {
-  handleInput();
-  render(10);
-}
-
-int KeyboardEntryActivity::getRowLength(int row) const {
   if (row < 0 || row >= NUM_ROWS) return 0;
 
   // Return actual length of each row based on keyboard layout
@@ -65,7 +72,7 @@ int KeyboardEntryActivity::getRowLength(int row) const {
     case 3:
       return 10;  // zxcvbnm,./
     case 4:
-      return 10;  // ^, space (5 wide), backspace, OK (2 wide)
+      return 10;  // caps (2 wide), space (5 wide), backspace (2 wide), OK
     default:
       return 0;
   }
@@ -82,8 +89,8 @@ char KeyboardEntryActivity::getSelectedChar() const {
 
 void KeyboardEntryActivity::handleKeyPress() {
   // Handle special row (bottom row with shift, space, backspace, done)
-  if (selectedRow == SHIFT_ROW) {
+  if (selectedRow == SPECIAL_ROW) {
-    if (selectedCol == SHIFT_COL) {
+    if (selectedCol >= SHIFT_COL && selectedCol < SPACE_COL) {
       // Shift toggle
       shiftActive = !shiftActive;
       return;
@@ -97,7 +104,7 @@ void KeyboardEntryActivity::handleKeyPress() {
       return;
     }
 
-    if (selectedCol == BACKSPACE_COL) {
+    if (selectedCol >= BACKSPACE_COL && selectedCol < DONE_COL) {
       // Backspace
       if (!text.empty()) {
         text.pop_back();
@@ -107,7 +114,6 @@ void KeyboardEntryActivity::handleKeyPress() {
 
     if (selectedCol >= DONE_COL) {
       // Done button
-      complete = true;
       if (onComplete) {
         onComplete(text);
       }
@@ -116,8 +122,11 @@ void KeyboardEntryActivity::handleKeyPress() {
   }
 
   // Regular character
-  char c = getSelectedChar();
+  const char c = getSelectedChar();
-  if (c != '\0' && c != '^' && c != '_' && c != '<') {
+  if (c == '\0') {
+    return;
+  }
+
   if (maxLength == 0 || text.length() < maxLength) {
     text += c;
     // Auto-disable shift after typing a letter
@@ -125,33 +134,49 @@ void KeyboardEntryActivity::handleKeyPress() {
       shiftActive = false;
     }
   }
-  }
 }
 
-bool KeyboardEntryActivity::handleInput() {
+void KeyboardEntryActivity::loop() {
-  if (complete || cancelled) {
-    return false;
-  }
-
-  bool handled = false;
-
   // Navigation
   if (inputManager.wasPressed(InputManager::BTN_UP)) {
     if (selectedRow > 0) {
       selectedRow--;
       // Clamp column to valid range for new row
-      int maxCol = getRowLength(selectedRow) - 1;
+      const int maxCol = getRowLength(selectedRow) - 1;
       if (selectedCol > maxCol) selectedCol = maxCol;
     }
-    handled = true;
+    updateRequired = true;
-  } else if (inputManager.wasPressed(InputManager::BTN_DOWN)) {
+  }
+
+  if (inputManager.wasPressed(InputManager::BTN_DOWN)) {
     if (selectedRow < NUM_ROWS - 1) {
       selectedRow++;
-      int maxCol = getRowLength(selectedRow) - 1;
+      const int maxCol = getRowLength(selectedRow) - 1;
       if (selectedCol > maxCol) selectedCol = maxCol;
     }
-    handled = true;
+    updateRequired = true;
-  } else if (inputManager.wasPressed(InputManager::BTN_LEFT)) {
+  }
+
+  if (inputManager.wasPressed(InputManager::BTN_LEFT)) {
+    // Special bottom row case
+    if (selectedRow == SPECIAL_ROW) {
+      // Bottom row has special key widths
+      if (selectedCol >= SHIFT_COL && selectedCol < SPACE_COL) {
+        // In shift key, do nothing
+      } else if (selectedCol >= SPACE_COL && selectedCol < BACKSPACE_COL) {
+        // In space bar, move to shift
+        selectedCol = SHIFT_COL;
+      } else if (selectedCol >= BACKSPACE_COL && selectedCol < DONE_COL) {
+        // In backspace, move to space
+        selectedCol = SPACE_COL;
+      } else if (selectedCol >= DONE_COL) {
+        // At done button, move to backspace
+        selectedCol = BACKSPACE_COL;
+      }
+      updateRequired = true;
+      return;
+    }
+
     if (selectedCol > 0) {
       selectedCol--;
     } else if (selectedRow > 0) {
@@ -159,9 +184,31 @@ bool KeyboardEntryActivity::handleInput() {
       selectedRow--;
       selectedCol = getRowLength(selectedRow) - 1;
     }
-    handled = true;
+    updateRequired = true;
-  } else if (inputManager.wasPressed(InputManager::BTN_RIGHT)) {
+  }
-    int maxCol = getRowLength(selectedRow) - 1;
+
+  if (inputManager.wasPressed(InputManager::BTN_RIGHT)) {
+    const int maxCol = getRowLength(selectedRow) - 1;
+
+    // Special bottom row case
+    if (selectedRow == SPECIAL_ROW) {
+      // Bottom row has special key widths
+      if (selectedCol >= SHIFT_COL && selectedCol < SPACE_COL) {
+        // In shift key, move to space
+        selectedCol = SPACE_COL;
+      } else if (selectedCol >= SPACE_COL && selectedCol < BACKSPACE_COL) {
+        // In space bar, move to backspace
+        selectedCol = BACKSPACE_COL;
+      } else if (selectedCol >= BACKSPACE_COL && selectedCol < DONE_COL) {
+        // In backspace, move to done
+        selectedCol = DONE_COL;
+      } else if (selectedCol >= DONE_COL) {
+        // At done button, do nothing
+      }
+      updateRequired = true;
+      return;
+    }
+
     if (selectedCol < maxCol) {
       selectedCol++;
     } else if (selectedRow < NUM_ROWS - 1) {
@@ -169,35 +216,34 @@ bool KeyboardEntryActivity::handleInput() {
       selectedRow++;
       selectedCol = 0;
     }
-    handled = true;
+    updateRequired = true;
   }
 
   // Selection
   if (inputManager.wasPressed(InputManager::BTN_CONFIRM)) {
     handleKeyPress();
-    handled = true;
+    updateRequired = true;
   }
 
   // Cancel
   if (inputManager.wasPressed(InputManager::BTN_BACK)) {
-    cancelled = true;
     if (onCancel) {
       onCancel();
     }
-    handled = true;
+    updateRequired = true;
   }
-
-  return handled;
 }
 
-void KeyboardEntryActivity::render(int startY) const {
+void KeyboardEntryActivity::render() const {
   const auto pageWidth = GfxRenderer::getScreenWidth();
 
+  renderer.clearScreen();
+
   // Draw title
   renderer.drawCenteredText(UI_FONT_ID, startY, title.c_str(), true, REGULAR);
 
   // Draw input field
-  int inputY = startY + 22;
+  const int inputY = startY + 22;
   renderer.drawText(UI_FONT_ID, 10, inputY, "[");
 
   std::string displayText;
@@ -211,9 +257,9 @@ void KeyboardEntryActivity::render(int startY) const {
   displayText += "_";
 
   // Truncate if too long for display - use actual character width from font
-  int charWidth = renderer.getSpaceWidth(UI_FONT_ID);
+  int approxCharWidth = renderer.getSpaceWidth(UI_FONT_ID);
-  if (charWidth < 1) charWidth = 8;  // Fallback to approximate width
+  if (approxCharWidth < 1) approxCharWidth = 8;  // Fallback to approximate width
-  int maxDisplayLen = (pageWidth - 40) / charWidth;
+  const int maxDisplayLen = (pageWidth - 40) / approxCharWidth;
   if (displayText.length() > static_cast<size_t>(maxDisplayLen)) {
     displayText = "..." + displayText.substr(displayText.length() - maxDisplayLen + 3);
   }
@@ -222,22 +268,22 @@ void KeyboardEntryActivity::render(int startY) const {
   renderer.drawText(UI_FONT_ID, pageWidth - 15, inputY, "]");
 
   // Draw keyboard - use compact spacing to fit 5 rows on screen
-  int keyboardStartY = inputY + 25;
+  const int keyboardStartY = inputY + 25;
-  const int keyWidth = 18;
+  constexpr int keyWidth = 18;
-  const int keyHeight = 18;
+  constexpr int keyHeight = 18;
-  const int keySpacing = 3;
+  constexpr int keySpacing = 3;
 
   const char* const* layout = shiftActive ? keyboardShift : keyboard;
 
   // Calculate left margin to center the longest row (13 keys)
-  int maxRowWidth = KEYS_PER_ROW * (keyWidth + keySpacing);
+  constexpr int maxRowWidth = KEYS_PER_ROW * (keyWidth + keySpacing);
-  int leftMargin = (pageWidth - maxRowWidth) / 2;
+  const int leftMargin = (pageWidth - maxRowWidth) / 2;
 
   for (int row = 0; row < NUM_ROWS; row++) {
-    int rowY = keyboardStartY + row * (keyHeight + keySpacing);
+    const int rowY = keyboardStartY + row * (keyHeight + keySpacing);
 
     // Left-align all rows for consistent navigation
-    int startX = leftMargin;
+    const int startX = leftMargin;
 
     // Handle bottom row (row 4) specially with proper multi-column keys
     if (row == 4) {
@@ -247,64 +293,37 @@ void KeyboardEntryActivity::render(int startY) const {
       int currentX = startX;
 
       // CAPS key (logical col 0, spans 2 key widths)
-      int capsWidth = 2 * keyWidth + keySpacing;
+      const bool capsSelected = (selectedRow == 4 && selectedCol >= SHIFT_COL && selectedCol < SPACE_COL);
-      bool capsSelected = (selectedRow == 4 && selectedCol == SHIFT_COL);
+      renderItemWithSelector(currentX + 2, rowY, shiftActive ? "CAPS" : "caps", capsSelected);
-      if (capsSelected) {
+      currentX += 2 * (keyWidth + keySpacing);
-        renderer.drawText(UI_FONT_ID, currentX - 2, rowY, "[");
-        renderer.drawText(UI_FONT_ID, currentX + capsWidth - 4, rowY, "]");
-      }
-      renderer.drawText(UI_FONT_ID, currentX + 2, rowY, shiftActive ? "CAPS" : "caps");
-      currentX += capsWidth + keySpacing;
 
       // Space bar (logical cols 2-6, spans 5 key widths)
-      int spaceWidth = 5 * keyWidth + 4 * keySpacing;
+      const bool spaceSelected = (selectedRow == 4 && selectedCol >= SPACE_COL && selectedCol < BACKSPACE_COL);
-      bool spaceSelected = (selectedRow == 4 && selectedCol >= SPACE_COL && selectedCol < BACKSPACE_COL);
+      const int spaceTextWidth = renderer.getTextWidth(UI_FONT_ID, "_____");
-      if (spaceSelected) {
+      const int spaceXWidth = 5 * (keyWidth + keySpacing);
-        renderer.drawText(UI_FONT_ID, currentX - 2, rowY, "[");
+      const int spaceXPos = currentX + (spaceXWidth - spaceTextWidth) / 2;
-        renderer.drawText(UI_FONT_ID, currentX + spaceWidth - 4, rowY, "]");
+      renderItemWithSelector(spaceXPos, rowY, "_____", spaceSelected);
-      }
+      currentX += spaceXWidth;
-      // Draw centered underscores for space bar
-      int spaceTextX = currentX + (spaceWidth / 2) - 12;
-      renderer.drawText(UI_FONT_ID, spaceTextX, rowY, "_____");
-      currentX += spaceWidth + keySpacing;
 
       // Backspace key (logical col 7, spans 2 key widths)
-      int bsWidth = 2 * keyWidth + keySpacing;
+      const bool bsSelected = (selectedRow == 4 && selectedCol >= BACKSPACE_COL && selectedCol < DONE_COL);
-      bool bsSelected = (selectedRow == 4 && selectedCol == BACKSPACE_COL);
+      renderItemWithSelector(currentX + 2, rowY, "<-", bsSelected);
-      if (bsSelected) {
+      currentX += 2 * (keyWidth + keySpacing);
-        renderer.drawText(UI_FONT_ID, currentX - 2, rowY, "[");
-        renderer.drawText(UI_FONT_ID, currentX + bsWidth - 4, rowY, "]");
-      }
-      renderer.drawText(UI_FONT_ID, currentX + 6, rowY, "<-");
-      currentX += bsWidth + keySpacing;
 
       // OK button (logical col 9, spans 2 key widths)
-      int okWidth = 2 * keyWidth + keySpacing;
+      const bool okSelected = (selectedRow == 4 && selectedCol >= DONE_COL);
-      bool okSelected = (selectedRow == 4 && selectedCol >= DONE_COL);
+      renderItemWithSelector(currentX + 2, rowY, "OK", okSelected);
-      if (okSelected) {
-        renderer.drawText(UI_FONT_ID, currentX - 2, rowY, "[");
-        renderer.drawText(UI_FONT_ID, currentX + okWidth - 4, rowY, "]");
-      }
-      renderer.drawText(UI_FONT_ID, currentX + 8, rowY, "OK");
-
     } else {
       // Regular rows: render each key individually
       for (int col = 0; col < getRowLength(row); col++) {
-        int keyX = startX + col * (keyWidth + keySpacing);
-
         // Get the character to display
-        char c = layout[row][col];
+        const char c = layout[row][col];
         std::string keyLabel(1, c);
+        const int charWidth = renderer.getTextWidth(UI_FONT_ID, keyLabel.c_str());
 
-        // Draw selection highlight
+        const int keyX = startX + col * (keyWidth + keySpacing) + (keyWidth - charWidth) / 2;
-        bool isSelected = (row == selectedRow && col == selectedCol);
+        const bool isSelected = row == selectedRow && col == selectedCol;
-
+        renderItemWithSelector(keyX, rowY, keyLabel.c_str(), isSelected);
-        if (isSelected) {
-          renderer.drawText(UI_FONT_ID, keyX - 2, rowY, "[");
-          renderer.drawText(UI_FONT_ID, keyX + keyWidth - 4, rowY, "]");
-        }
-
-        renderer.drawText(UI_FONT_ID, keyX + 2, rowY, keyLabel.c_str());
       }
     }
   }
@@ -312,4 +331,15 @@ void KeyboardEntryActivity::render(int startY) const {
   // Draw help text at absolute bottom of screen (consistent with other screens)
   const auto pageHeight = GfxRenderer::getScreenHeight();
   renderer.drawText(SMALL_FONT_ID, 10, pageHeight - 30, "Navigate: D-pad | Select: OK | Cancel: BACK");
+  renderer.displayBuffer();
+}
+
+void KeyboardEntryActivity::renderItemWithSelector(const int x, const int y, const char* item,
+                                                   const bool isSelected) const {
+  if (isSelected) {
+    const int itemWidth = renderer.getTextWidth(UI_FONT_ID, item);
+    renderer.drawText(UI_FONT_ID, x - 6, y, "[");
+    renderer.drawText(UI_FONT_ID, x + itemWidth, y, "]");
+  }
+  renderer.drawText(UI_FONT_ID, x, y, item);
 }

src/activities/util/KeyboardEntryActivity.h

@@ -1,9 +1,13 @@
 #pragma once
 #include <GfxRenderer.h>
 #include <InputManager.h>
+#include <freertos/FreeRTOS.h>
+#include <freertos/semphr.h>
+#include <freertos/task.h>
 
 #include <functional>
 #include <string>
+#include <utility>
 
 #include "../Activity.h"
 
@@ -30,58 +34,24 @@ class KeyboardEntryActivity : public Activity {
    * @param inputManager Reference to InputManager for handling input
    * @param title Title to display above the keyboard
    * @param initialText Initial text to show in the input field
+   * @param startY Y position to start rendering the keyboard
    * @param maxLength Maximum length of input text (0 for unlimited)
    * @param isPassword If true, display asterisks instead of actual characters
+   * @param onComplete Callback invoked when input is complete
+   * @param onCancel Callback invoked when input is cancelled
    */
-  KeyboardEntryActivity(GfxRenderer& renderer, InputManager& inputManager, const std::string& title = "Enter Text",
+  explicit KeyboardEntryActivity(GfxRenderer& renderer, InputManager& inputManager, std::string title = "Enter Text",
-                        const std::string& initialText = "", size_t maxLength = 0, bool isPassword = false);
+                                 std::string initialText = "", const int startY = 10, const size_t maxLength = 0,
-
+                                 const bool isPassword = false, OnCompleteCallback onComplete = nullptr,
-  /**
+                                 OnCancelCallback onCancel = nullptr)
-   * Handle button input. Call this in your main loop.
+      : Activity("KeyboardEntry", renderer, inputManager),
-   * @return true if input was handled, false otherwise
+        title(std::move(title)),
-   */
+        text(std::move(initialText)),
-  bool handleInput();
+        startY(startY),
-
+        maxLength(maxLength),
-  /**
+        isPassword(isPassword),
-   * Render the keyboard at the specified Y position.
+        onComplete(std::move(onComplete)),
-   * @param startY Y-coordinate where keyboard rendering starts (default 10)
+        onCancel(std::move(onCancel)) {}
-   */
-  void render(int startY = 10) const;
-
-  /**
-   * Get the current text entered by the user.
-   */
-  const std::string& getText() const { return text; }
-
-  /**
-   * Set the current text.
-   */
-  void setText(const std::string& newText);
-
-  /**
-   * Check if the user has completed text entry (pressed OK on Done).
-   */
-  bool isComplete() const { return complete; }
-
-  /**
-   * Check if the user has cancelled text entry.
-   */
-  bool isCancelled() const { return cancelled; }
-
-  /**
-   * Reset the keyboard state for reuse.
-   */
-  void reset(const std::string& newTitle = "", const std::string& newInitialText = "");
-
-  /**
-   * Set callback for when input is complete.
-   */
-  void setOnComplete(OnCompleteCallback callback) { onComplete = callback; }
-
-  /**
-   * Set callback for when input is cancelled.
-   */
-  void setOnCancel(OnCancelCallback callback) { onCancel = callback; }
 
   // Activity overrides
   void onEnter() override;
@@ -90,16 +60,18 @@ class KeyboardEntryActivity : public Activity {
 
  private:
   std::string title;
+  int startY;
   std::string text;
   size_t maxLength;
   bool isPassword;
+  TaskHandle_t displayTaskHandle = nullptr;
+  SemaphoreHandle_t renderingMutex = nullptr;
+  bool updateRequired = false;
 
   // Keyboard state
   int selectedRow = 0;
   int selectedCol = 0;
   bool shiftActive = false;
-  bool complete = false;
-  bool cancelled = false;
 
   // Callbacks
   OnCompleteCallback onComplete;
@@ -112,16 +84,17 @@ class KeyboardEntryActivity : public Activity {
   static const char* const keyboardShift[NUM_ROWS];
 
   // Special key positions (bottom row)
-  static constexpr int SHIFT_ROW = 4;
+  static constexpr int SPECIAL_ROW = 4;
   static constexpr int SHIFT_COL = 0;
-  static constexpr int SPACE_ROW = 4;
   static constexpr int SPACE_COL = 2;
-  static constexpr int BACKSPACE_ROW = 4;
   static constexpr int BACKSPACE_COL = 7;
-  static constexpr int DONE_ROW = 4;
   static constexpr int DONE_COL = 9;
 
+  static void taskTrampoline(void* param);
+  [[noreturn]] void displayTaskLoop();
   char getSelectedChar() const;
   void handleKeyPress();
   int getRowLength(int row) const;
+  void render() const;
+  void renderItemWithSelector(int x, int y, const char* item, bool isSelected) const;
 };

src/config.h

@@ -26,4 +26,4 @@
  *    "./lib/EpdFont/builtinFonts/pixelarial14.h",
  *  ].map{|f| Digest::SHA256.hexdigest(File.read(f)).to_i(16) }.sum % (2 ** 32) - (2 ** 31)'
  */
-#define SMALL_FONT_ID (-139796914)
+#define SMALL_FONT_ID 1482513144

src/html/FilesPageFooter.html

@@ -1,251 +0,0 @@
-   <div class="card">
-    <p style="text-align: center; color: #95a5a6; margin: 0;">
-      CrossPoint E-Reader • Open Source
-    </p>
-  </div>
-  
-  <!-- Upload Modal -->
-  <div class="modal-overlay" id="uploadModal">
-    <div class="modal">
-      <button class="modal-close" onclick="closeUploadModal()">&times;</button>
-      <h3>📤 Upload eBook</h3>
-      <div class="upload-form">
-        <p class="file-info">Select an .epub file to upload to <strong id="uploadPathDisplay"></strong></p>
-        <input type="file" id="fileInput" accept=".epub" onchange="validateFile()">
-        <button id="uploadBtn" class="upload-btn" onclick="uploadFile()" disabled>Upload</button>
-        <div id="progress-container">
-          <div id="progress-bar"><div id="progress-fill"></div></div>
-          <div id="progress-text"></div>
-        </div>
-      </div>
-    </div>
-  </div>
-  
-  <!-- New Folder Modal -->
-  <div class="modal-overlay" id="folderModal">
-    <div class="modal">
-      <button class="modal-close" onclick="closeFolderModal()">&times;</button>
-      <h3>📁 New Folder</h3>
-      <div class="folder-form">
-        <p class="file-info">Create a new folder in <strong id="folderPathDisplay"></strong></p>
-        <input type="text" id="folderName" class="folder-input" placeholder="Folder name...">
-        <button class="folder-btn" onclick="createFolder()">Create Folder</button>
-      </div>
-    </div>
-  </div>
-  
-  <!-- Delete Confirmation Modal -->
-  <div class="modal-overlay" id="deleteModal">
-    <div class="modal">
-      <button class="modal-close" onclick="closeDeleteModal()">&times;</button>
-      <h3>🗑️ Delete Item</h3>
-      <div class="folder-form">
-        <p class="delete-warning">⚠️ This action cannot be undone!</p>
-        <p class="file-info">Are you sure you want to delete:</p>
-        <p class="delete-item-name" id="deleteItemName"></p>
-        <input type="hidden" id="deleteItemPath">
-        <input type="hidden" id="deleteItemType">
-        <button class="delete-btn-confirm" onclick="confirmDelete()">Delete</button>
-        <button class="delete-btn-cancel" onclick="closeDeleteModal()">Cancel</button>
-      </div>
-    </div>
-  </div>
-  
-  <script>
-    // Modal functions
-    function openUploadModal() {
-      const currentPath = document.getElementById('currentPath').value;
-      document.getElementById('uploadPathDisplay').textContent = currentPath === '/' ? '/ 🏠' : currentPath;
-      document.getElementById('uploadModal').classList.add('open');
-    }
-    
-    function closeUploadModal() {
-      document.getElementById('uploadModal').classList.remove('open');
-      document.getElementById('fileInput').value = '';
-      document.getElementById('uploadBtn').disabled = true;
-      document.getElementById('progress-container').style.display = 'none';
-      document.getElementById('progress-fill').style.width = '0%';
-      document.getElementById('progress-fill').style.backgroundColor = '#27ae60';
-    }
-    
-    function openFolderModal() {
-      const currentPath = document.getElementById('currentPath').value;
-      document.getElementById('folderPathDisplay').textContent = currentPath === '/' ? '/ 🏠' : currentPath;
-      document.getElementById('folderModal').classList.add('open');
-      document.getElementById('folderName').value = '';
-    }
-    
-    function closeFolderModal() {
-      document.getElementById('folderModal').classList.remove('open');
-    }
-    
-    // Close modals when clicking overlay
-    document.querySelectorAll('.modal-overlay').forEach(function(overlay) {
-      overlay.addEventListener('click', function(e) {
-        if (e.target === overlay) {
-          overlay.classList.remove('open');
-        }
-      });
-    });
-    
-    function validateFile() {
-      const fileInput = document.getElementById('fileInput');
-      const uploadBtn = document.getElementById('uploadBtn');
-      const file = fileInput.files[0];
-      
-      if (file) {
-        const fileName = file.name.toLowerCase();
-        if (!fileName.endsWith('.epub')) {
-          alert('Only .epub files are allowed!');
-          fileInput.value = '';
-          uploadBtn.disabled = true;
-          return;
-        }
-        uploadBtn.disabled = false;
-      } else {
-        uploadBtn.disabled = true;
-      }
-    }
-    
-    function uploadFile() {
-      const fileInput = document.getElementById('fileInput');
-      const file = fileInput.files[0];
-      const currentPath = document.getElementById('currentPath').value;
-      
-      if (!file) {
-        alert('Please select a file first!');
-        return;
-      }
-      
-      const fileName = file.name.toLowerCase();
-      if (!fileName.endsWith('.epub')) {
-        alert('Only .epub files are allowed!');
-        return;
-      }
-      
-      const formData = new FormData();
-      formData.append('file', file);
-      
-      const progressContainer = document.getElementById('progress-container');
-      const progressFill = document.getElementById('progress-fill');
-      const progressText = document.getElementById('progress-text');
-      const uploadBtn = document.getElementById('uploadBtn');
-      
-      progressContainer.style.display = 'block';
-      uploadBtn.disabled = true;
-      
-      const xhr = new XMLHttpRequest();
-      // Include path as query parameter since multipart form data doesn't make
-      // form fields available until after file upload completes
-      xhr.open('POST', '/upload?path=' + encodeURIComponent(currentPath), true);
-      
-      xhr.upload.onprogress = function(e) {
-        if (e.lengthComputable) {
-          const percent = Math.round((e.loaded / e.total) * 100);
-          progressFill.style.width = percent + '%';
-          progressText.textContent = 'Uploading: ' + percent + '%';
-        }
-      };
-      
-      xhr.onload = function() {
-        if (xhr.status === 200) {
-          progressText.textContent = 'Upload complete!';
-          setTimeout(function() {
-            window.location.reload();
-          }, 1000);
-        } else {
-          progressText.textContent = 'Upload failed: ' + xhr.responseText;
-          progressFill.style.backgroundColor = '#e74c3c';
-          uploadBtn.disabled = false;
-        }
-      };
-      
-      xhr.onerror = function() {
-        progressText.textContent = 'Upload failed - network error';
-        progressFill.style.backgroundColor = '#e74c3c';
-        uploadBtn.disabled = false;
-      };
-      
-      xhr.send(formData);
-    }
-    
-    function createFolder() {
-      const folderName = document.getElementById('folderName').value.trim();
-      const currentPath = document.getElementById('currentPath').value;
-      
-      if (!folderName) {
-        alert('Please enter a folder name!');
-        return;
-      }
-      
-      // Validate folder name (no special characters except underscore and hyphen)
-      const validName = /^[a-zA-Z0-9_\-]+$/.test(folderName);
-      if (!validName) {
-        alert('Folder name can only contain letters, numbers, underscores, and hyphens.');
-        return;
-      }
-      
-      const formData = new FormData();
-      formData.append('name', folderName);
-      formData.append('path', currentPath);
-      
-      const xhr = new XMLHttpRequest();
-      xhr.open('POST', '/mkdir', true);
-      
-      xhr.onload = function() {
-        if (xhr.status === 200) {
-          window.location.reload();
-        } else {
-          alert('Failed to create folder: ' + xhr.responseText);
-        }
-      };
-      
-      xhr.onerror = function() {
-        alert('Failed to create folder - network error');
-      };
-      
-      xhr.send(formData);
-    }
-    
-    // Delete functions
-    function openDeleteModal(name, path, isFolder) {
-      document.getElementById('deleteItemName').textContent = (isFolder ? '📁 ' : '📄 ') + name;
-      document.getElementById('deleteItemPath').value = path;
-      document.getElementById('deleteItemType').value = isFolder ? 'folder' : 'file';
-      document.getElementById('deleteModal').classList.add('open');
-    }
-    
-    function closeDeleteModal() {
-      document.getElementById('deleteModal').classList.remove('open');
-    }
-    
-    function confirmDelete() {
-      const path = document.getElementById('deleteItemPath').value;
-      const itemType = document.getElementById('deleteItemType').value;
-      
-      const formData = new FormData();
-      formData.append('path', path);
-      formData.append('type', itemType);
-      
-      const xhr = new XMLHttpRequest();
-      xhr.open('POST', '/delete', true);
-      
-      xhr.onload = function() {
-        if (xhr.status === 200) {
-          window.location.reload();
-        } else {
-          alert('Failed to delete: ' + xhr.responseText);
-          closeDeleteModal();
-        }
-      };
-      
-      xhr.onerror = function() {
-        alert('Failed to delete - network error');
-        closeDeleteModal();
-      };
-      
-      xhr.send(formData);
-    }
-  </script>
-</body>
-</html>

src/html/FilesPageHeader.html

@@ -1,472 +0,0 @@
-<!DOCTYPE html>
-<html>
-  <head>
-    <meta charset="UTF-8" />
-    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
-    <title>CrossPoint Reader - Files</title>
-    <style>
-      body {
-        font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
-          Oxygen, Ubuntu, sans-serif;
-        max-width: 800px;
-        margin: 0 auto;
-        padding: 20px;
-        background-color: #f5f5f5;
-        color: #333;
-      }
-      h1 {
-        color: #2c3e50;
-        margin-bottom: 5px;
-      }
-      h2 {
-        color: #34495e;
-        margin-top: 0;
-      }
-      .card {
-        background: white;
-        border-radius: 8px;
-        padding: 20px;
-        margin: 15px 0;
-        box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
-      }
-      .page-header {
-        display: flex;
-        justify-content: space-between;
-        align-items: center;
-        flex-wrap: wrap;
-        gap: 15px;
-        margin-bottom: 20px;
-        padding-bottom: 15px;
-        border-bottom: 2px solid #3498db;
-      }
-      .page-header-left {
-        display: flex;
-        align-items: baseline;
-        gap: 12px;
-        flex-wrap: wrap;
-      }
-      .breadcrumb-inline {
-        color: #7f8c8d;
-        font-size: 1.1em;
-      }
-      .breadcrumb-inline a {
-        color: #3498db;
-        text-decoration: none;
-      }
-      .breadcrumb-inline a:hover {
-        text-decoration: underline;
-      }
-      .breadcrumb-inline .sep {
-        margin: 0 6px;
-        color: #bdc3c7;
-      }
-      .breadcrumb-inline .current {
-        color: #2c3e50;
-        font-weight: 500;
-      }
-      .nav-links {
-        margin: 20px 0;
-      }
-      .nav-links a {
-        display: inline-block;
-        padding: 10px 20px;
-        background-color: #3498db;
-        color: white;
-        text-decoration: none;
-        border-radius: 4px;
-        margin-right: 10px;
-      }
-      .nav-links a:hover {
-        background-color: #2980b9;
-      }
-      /* Action buttons */
-      .action-buttons {
-        display: flex;
-        gap: 10px;
-      }
-      .action-btn {
-        color: white;
-        padding: 10px 16px;
-        border: none;
-        border-radius: 4px;
-        cursor: pointer;
-        font-size: 0.95em;
-        font-weight: 600;
-        display: flex;
-        align-items: center;
-        gap: 6px;
-      }
-      .upload-action-btn {
-        background-color: #27ae60;
-      }
-      .upload-action-btn:hover {
-        background-color: #219a52;
-      }
-      .folder-action-btn {
-        background-color: #f39c12;
-      }
-      .folder-action-btn:hover {
-        background-color: #d68910;
-      }
-      /* Upload modal */
-      .modal-overlay {
-        display: none;
-        position: fixed;
-        top: 0;
-        left: 0;
-        right: 0;
-        bottom: 0;
-        background: rgba(0, 0, 0, 0.5);
-        z-index: 200;
-        justify-content: center;
-        align-items: center;
-      }
-      .modal-overlay.open {
-        display: flex;
-      }
-      .modal {
-        background: white;
-        border-radius: 8px;
-        padding: 25px;
-        max-width: 450px;
-        width: 90%;
-        box-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
-      }
-      .modal h3 {
-        margin: 0 0 15px 0;
-        color: #2c3e50;
-      }
-      .modal-close {
-        float: right;
-        background: none;
-        border: none;
-        font-size: 1.5em;
-        cursor: pointer;
-        color: #7f8c8d;
-        line-height: 1;
-      }
-      .modal-close:hover {
-        color: #2c3e50;
-      }
-      .file-table {
-        width: 100%;
-        border-collapse: collapse;
-      }
-      .file-table th,
-      .file-table td {
-        padding: 12px;
-        text-align: left;
-        border-bottom: 1px solid #eee;
-      }
-      .file-table th {
-        background-color: #f8f9fa;
-        font-weight: 600;
-        color: #7f8c8d;
-      }
-      .file-table tr:hover {
-        background-color: #f8f9fa;
-      }
-      .epub-file {
-        background-color: #e8f6e9 !important;
-      }
-      .epub-file:hover {
-        background-color: #d4edda !important;
-      }
-      .folder-row {
-        background-color: #fff9e6 !important;
-      }
-      .folder-row:hover {
-        background-color: #fff3cd !important;
-      }
-      .epub-badge {
-        display: inline-block;
-        padding: 2px 8px;
-        background-color: #27ae60;
-        color: white;
-        border-radius: 10px;
-        font-size: 0.75em;
-        margin-left: 8px;
-      }
-      .folder-badge {
-        display: inline-block;
-        padding: 2px 8px;
-        background-color: #f39c12;
-        color: white;
-        border-radius: 10px;
-        font-size: 0.75em;
-        margin-left: 8px;
-      }
-      .file-icon {
-        margin-right: 8px;
-      }
-      .folder-link {
-        color: #2c3e50;
-        text-decoration: none;
-        cursor: pointer;
-      }
-      .folder-link:hover {
-        color: #3498db;
-        text-decoration: underline;
-      }
-      .upload-form {
-        margin-top: 10px;
-      }
-      .upload-form input[type="file"] {
-        margin: 10px 0;
-        width: 100%;
-      }
-      .upload-btn {
-        background-color: #27ae60;
-        color: white;
-        padding: 10px 20px;
-        border: none;
-        border-radius: 4px;
-        cursor: pointer;
-        font-size: 1em;
-        width: 100%;
-      }
-      .upload-btn:hover {
-        background-color: #219a52;
-      }
-      .upload-btn:disabled {
-        background-color: #95a5a6;
-        cursor: not-allowed;
-      }
-      .file-info {
-        color: #7f8c8d;
-        font-size: 0.85em;
-        margin: 8px 0;
-      }
-      .no-files {
-        text-align: center;
-        color: #95a5a6;
-        padding: 40px;
-        font-style: italic;
-      }
-      .message {
-        padding: 15px;
-        border-radius: 4px;
-        margin: 15px 0;
-      }
-      .message.success {
-        background-color: #d4edda;
-        color: #155724;
-        border: 1px solid #c3e6cb;
-      }
-      .message.error {
-        background-color: #f8d7da;
-        color: #721c24;
-        border: 1px solid #f5c6cb;
-      }
-      .contents-header {
-        display: flex;
-        justify-content: space-between;
-        align-items: center;
-        margin-bottom: 12px;
-      }
-      .contents-title {
-        font-size: 1.1em;
-        font-weight: 600;
-        color: #34495e;
-        margin: 0;
-      }
-      .summary-inline {
-        color: #7f8c8d;
-        font-size: 0.9em;
-      }
-      #progress-container {
-        display: none;
-        margin-top: 10px;
-      }
-      #progress-bar {
-        width: 100%;
-        height: 20px;
-        background-color: #e0e0e0;
-        border-radius: 10px;
-        overflow: hidden;
-      }
-      #progress-fill {
-        height: 100%;
-        background-color: #27ae60;
-        width: 0%;
-        transition: width 0.3s;
-      }
-      #progress-text {
-        text-align: center;
-        margin-top: 5px;
-        font-size: 0.9em;
-        color: #7f8c8d;
-      }
-      .folder-form {
-        margin-top: 10px;
-      }
-      .folder-input {
-        width: 100%;
-        padding: 10px;
-        border: 1px solid #ddd;
-        border-radius: 4px;
-        font-size: 1em;
-        margin-bottom: 10px;
-        box-sizing: border-box;
-      }
-      .folder-btn {
-        background-color: #f39c12;
-        color: white;
-        padding: 10px 20px;
-        border: none;
-        border-radius: 4px;
-        cursor: pointer;
-        font-size: 1em;
-        width: 100%;
-      }
-      .folder-btn:hover {
-        background-color: #d68910;
-      }
-      /* Delete button styles */
-      .delete-btn {
-        background: none;
-        border: none;
-        cursor: pointer;
-        font-size: 1.1em;
-        padding: 4px 8px;
-        border-radius: 4px;
-        color: #95a5a6;
-        transition: all 0.15s;
-      }
-      .delete-btn:hover {
-        background-color: #fee;
-        color: #e74c3c;
-      }
-      .actions-col {
-        width: 60px;
-        text-align: center;
-      }
-      /* Delete modal */
-      .delete-warning {
-        color: #e74c3c;
-        font-weight: 600;
-        margin: 10px 0;
-      }
-      .delete-item-name {
-        font-weight: 600;
-        color: #2c3e50;
-        word-break: break-all;
-      }
-      .delete-btn-confirm {
-        background-color: #e74c3c;
-        color: white;
-        padding: 10px 20px;
-        border: none;
-        border-radius: 4px;
-        cursor: pointer;
-        font-size: 1em;
-        width: 100%;
-      }
-      .delete-btn-confirm:hover {
-        background-color: #c0392b;
-      }
-      .delete-btn-cancel {
-        background-color: #95a5a6;
-        color: white;
-        padding: 10px 20px;
-        border: none;
-        border-radius: 4px;
-        cursor: pointer;
-        font-size: 1em;
-        width: 100%;
-        margin-top: 10px;
-      }
-      .delete-btn-cancel:hover {
-        background-color: #7f8c8d;
-      }
-      /* Mobile responsive styles */
-      @media (max-width: 600px) {
-        body {
-          padding: 10px;
-          font-size: 14px;
-        }
-        .card {
-          padding: 12px;
-          margin: 10px 0;
-        }
-        .page-header {
-          gap: 10px;
-          margin-bottom: 12px;
-          padding-bottom: 10px;
-        }
-        .page-header-left {
-          gap: 8px;
-        }
-        h1 {
-          font-size: 1.3em;
-        }
-        .breadcrumb-inline {
-          font-size: 0.95em;
-        }
-        .nav-links a {
-          padding: 8px 12px;
-          margin-right: 6px;
-          font-size: 0.9em;
-        }
-        .action-buttons {
-          gap: 6px;
-        }
-        .action-btn {
-          padding: 8px 10px;
-          font-size: 0.85em;
-        }
-        .file-table th,
-        .file-table td {
-          padding: 8px 6px;
-          font-size: 0.9em;
-        }
-        .file-table th {
-          font-size: 0.85em;
-        }
-        .file-icon {
-          margin-right: 4px;
-        }
-        .epub-badge,
-        .folder-badge {
-          padding: 2px 5px;
-          font-size: 0.65em;
-          margin-left: 4px;
-        }
-        .contents-header {
-          margin-bottom: 8px;
-          flex-wrap: wrap;
-          gap: 4px;
-        }
-        .contents-title {
-          font-size: 1em;
-        }
-        .summary-inline {
-          font-size: 0.8em;
-        }
-        .modal {
-          padding: 15px;
-        }
-        .modal h3 {
-          font-size: 1.1em;
-        }
-        .actions-col {
-          width: 40px;
-        }
-        .delete-btn {
-          font-size: 1em;
-          padding: 2px 4px;
-        }
-        .no-files {
-          padding: 20px;
-          font-size: 0.9em;
-        }
-      }
-    </style>
-  </head>
-  <body>
-    <div class="nav-links">
-      <a href="/">Home</a>
-      <a href="/files">File Manager</a>
-    </div>
-  </body>
-</html>

src/main.cpp

@@ -5,7 +5,6 @@
 #include <InputManager.h>
 #include <SD.h>
 #include <SPI.h>
-#include <WiFi.h>
 #include <builtinFonts/bookerly_2b.h>
 #include <builtinFonts/bookerly_bold_2b.h>
 #include <builtinFonts/bookerly_bold_italic_2b.h>
@@ -61,6 +60,9 @@ EpdFontFamily ubuntuFontFamily(&ubuntu10Font, &ubuntuBold10Font);
 
 // Auto-sleep timeout (10 minutes of inactivity)
 constexpr unsigned long AUTO_SLEEP_TIMEOUT_MS = 10 * 60 * 1000;
+// measurement of power button press duration calibration value
+unsigned long t1 = 0;
+unsigned long t2 = 0;
 
 void exitActivity() {
   if (currentActivity) {
@@ -80,6 +82,10 @@ void verifyWakeupLongPress() {
   // Give the user up to 1000ms to start holding the power button, and must hold for SETTINGS.getPowerButtonDuration()
   const auto start = millis();
   bool abort = false;
+  // It takes us some time to wake up from deep sleep, so we need to subtract that from the duration
+  uint16_t calibration = 25;
+  uint16_t calibratedPressDuration =
+      (calibration < SETTINGS.getPowerButtonDuration()) ? SETTINGS.getPowerButtonDuration() - calibration : 1;
 
   inputManager.update();
   // Verify the user has actually pressed
@@ -88,13 +94,13 @@ void verifyWakeupLongPress() {
     inputManager.update();
   }
 
+  t2 = millis();
   if (inputManager.isPressed(InputManager::BTN_POWER)) {
     do {
       delay(10);
       inputManager.update();
-    } while (inputManager.isPressed(InputManager::BTN_POWER) &&
+    } while (inputManager.isPressed(InputManager::BTN_POWER) && inputManager.getHeldTime() < calibratedPressDuration);
-             inputManager.getHeldTime() < SETTINGS.getPowerButtonDuration());
+    abort = inputManager.getHeldTime() < calibratedPressDuration;
-    abort = inputManager.getHeldTime() < SETTINGS.getPowerButtonDuration();
   } else {
     abort = true;
   }
@@ -120,14 +126,12 @@ void enterDeepSleep() {
   exitActivity();
   enterNewActivity(new SleepActivity(renderer, inputManager));
 
-  Serial.printf("[%lu] [   ] Entering deep sleep.\n", millis());
-  delay(1000);  // Allow Serial buffer to empty and display to update
-
-  // Enable Wakeup on LOW (button press)
-  esp_deep_sleep_enable_gpio_wakeup(1ULL << InputManager::POWER_BUTTON_PIN, ESP_GPIO_WAKEUP_GPIO_LOW);
-
   einkDisplay.deepSleep();
-
+  Serial.printf("[%lu] [   ] Power button press calibration value: %lu ms\n", millis(), t2 - t1);
+  Serial.printf("[%lu] [   ] Entering deep sleep.\n", millis());
+  esp_deep_sleep_enable_gpio_wakeup(1ULL << InputManager::POWER_BUTTON_PIN, ESP_GPIO_WAKEUP_GPIO_LOW);
+  // Ensure that the power button has been released to avoid immediately turning back on if you're holding it
+  waitForPowerRelease();
   // Enter Deep Sleep
   esp_deep_sleep_start();
 }
@@ -138,6 +142,7 @@ void onGoToReader(const std::string& initialEpubPath) {
   enterNewActivity(new ReaderActivity(renderer, inputManager, initialEpubPath, onGoHome));
 }
 void onGoToReaderHome() { onGoToReader(std::string()); }
+void onContinueReading() { onGoToReader(APP_STATE.openEpubPath); }
 
 void onGoToFileTransfer() {
   exitActivity();
@@ -151,11 +156,27 @@ void onGoToSettings() {
 
 void onGoHome() {
   exitActivity();
-  enterNewActivity(new HomeActivity(renderer, inputManager, onGoToReaderHome, onGoToSettings, onGoToFileTransfer));
+  enterNewActivity(new HomeActivity(renderer, inputManager, onContinueReading, onGoToReaderHome, onGoToSettings,
+                                    onGoToFileTransfer));
+}
+
+void setupDisplayAndFonts() {
+  einkDisplay.begin();
+  Serial.printf("[%lu] [   ] Display initialized\n", millis());
+  renderer.insertFont(READER_FONT_ID, bookerlyFontFamily);
+  renderer.insertFont(UI_FONT_ID, ubuntuFontFamily);
+  renderer.insertFont(SMALL_FONT_ID, smallFontFamily);
+  Serial.printf("[%lu] [   ] Fonts setup\n", millis());
 }
 
 void setup() {
+  t1 = millis();
+
+  // Only start serial if USB connected
+  pinMode(UART0_RXD, INPUT);
+  if (digitalRead(UART0_RXD) == HIGH) {
     Serial.begin(115200);
+  }
 
   Serial.printf("[%lu] [   ] Starting CrossPoint version " CROSSPOINT_VERSION "\n", millis());
 
@@ -167,8 +188,10 @@ void setup() {
   SPI.begin(EPD_SCLK, SD_SPI_MISO, EPD_MOSI, EPD_CS);
 
   // SD Card Initialization
-  if (!SD.begin(SD_SPI_CS, SPI, SPI_FQ)) {
+  // We need 6 open files concurrently when parsing a new chapter
+  if (!SD.begin(SD_SPI_CS, SPI, SPI_FQ, "/sd", 6)) {
     Serial.printf("[%lu] [   ] SD card initialization failed\n", millis());
+    setupDisplayAndFonts();
     exitActivity();
     enterNewActivity(new FullScreenMessageActivity(renderer, inputManager, "SD card error", BOLD));
     return;
@@ -179,14 +202,7 @@ void setup() {
   // verify power button press duration after we've read settings.
   verifyWakeupLongPress();
 
-  // Initialize display
+  setupDisplayAndFonts();
-  einkDisplay.begin();
-  Serial.printf("[%lu] [   ] Display initialized\n", millis());
-
-  renderer.insertFont(READER_FONT_ID, bookerlyFontFamily);
-  renderer.insertFont(UI_FONT_ID, ubuntuFontFamily);
-  renderer.insertFont(SMALL_FONT_ID, smallFontFamily);
-  Serial.printf("[%lu] [   ] Fonts setup\n", millis());
 
   exitActivity();
   enterNewActivity(new BootActivity(renderer, inputManager));
@@ -195,7 +211,11 @@ void setup() {
   if (APP_STATE.openEpubPath.empty()) {
     onGoHome();
   } else {
-    onGoToReader(APP_STATE.openEpubPath);
+    // Clear app state to avoid getting into a boot loop if the epub doesn't load
+    const auto path = APP_STATE.openEpubPath;
+    APP_STATE.openEpubPath = "";
+    APP_STATE.saveToFile();
+    onGoToReader(path);
   }
 
   // Ensure we're not still holding the power button before leaving setup
@@ -203,20 +223,18 @@ void setup() {
 }
 
 void loop() {
-  static unsigned long lastLoopTime = 0;
   static unsigned long maxLoopDuration = 0;
-
+  const unsigned long loopStartTime = millis();
-  unsigned long loopStartTime = millis();
-
   static unsigned long lastMemPrint = 0;
+
+  inputManager.update();
+
   if (Serial && millis() - lastMemPrint >= 10000) {
     Serial.printf("[%lu] [MEM] Free: %d bytes, Total: %d bytes, Min Free: %d bytes\n", millis(), ESP.getFreeHeap(),
                   ESP.getHeapSize(), ESP.getMinFreeHeap());
     lastMemPrint = millis();
   }
 
-  inputManager.update();
-
   // Check for any user activity (button press or release)
   static unsigned long lastActivityTime = millis();
   if (inputManager.wasAnyPressed() || inputManager.wasAnyReleased()) {
@@ -230,20 +248,20 @@ void loop() {
     return;
   }
 
-  if (inputManager.wasReleased(InputManager::BTN_POWER) &&
+  if (inputManager.isPressed(InputManager::BTN_POWER) &&
       inputManager.getHeldTime() > SETTINGS.getPowerButtonDuration()) {
     enterDeepSleep();
     // This should never be hit as `enterDeepSleep` calls esp_deep_sleep_start
     return;
   }
 
-  unsigned long activityStartTime = millis();
+  const unsigned long activityStartTime = millis();
   if (currentActivity) {
     currentActivity->loop();
   }
-  unsigned long activityDuration = millis() - activityStartTime;
+  const unsigned long activityDuration = millis() - activityStartTime;
 
-  unsigned long loopDuration = millis() - loopStartTime;
+  const unsigned long loopDuration = millis() - loopStartTime;
   if (loopDuration > maxLoopDuration) {
     maxLoopDuration = loopDuration;
     if (maxLoopDuration > 50) {
@@ -252,8 +270,6 @@ void loop() {
     }
   }
 
-  lastLoopTime = loopStartTime;
-
   // Add delay at the end of the loop to prevent tight spinning
   // When an activity requests skip loop delay (e.g., webserver running), use yield() for faster response
   // Otherwise, use longer delay to save power

src/network/CrossPointWebServer.cpp

@@ -1,53 +1,20 @@
 #include "CrossPointWebServer.h"
 
+#include <ArduinoJson.h>
+#include <FsHelpers.h>
 #include <SD.h>
 #include <WiFi.h>
 
 #include <algorithm>
 
-#include "config.h"
+#include "html/FilesPageHtml.generated.h"
-#include "html/FilesPageFooterHtml.generated.h"
-#include "html/FilesPageHeaderHtml.generated.h"
 #include "html/HomePageHtml.generated.h"
 
 namespace {
-
 // Folders/files to hide from the web interface file browser
 // Note: Items starting with "." are automatically hidden
 const char* HIDDEN_ITEMS[] = {"System Volume Information", "XTCache"};
-const size_t HIDDEN_ITEMS_COUNT = sizeof(HIDDEN_ITEMS) / sizeof(HIDDEN_ITEMS[0]);
+constexpr size_t HIDDEN_ITEMS_COUNT = sizeof(HIDDEN_ITEMS) / sizeof(HIDDEN_ITEMS[0]);
-
-// Helper function to escape HTML special characters to prevent XSS
-String escapeHtml(const String& input) {
-  String output;
-  output.reserve(input.length() * 1.1);  // Pre-allocate with some extra space
-
-  for (size_t i = 0; i < input.length(); i++) {
-    char c = input.charAt(i);
-    switch (c) {
-      case '&':
-        output += "&amp;";
-        break;
-      case '<':
-        output += "&lt;";
-        break;
-      case '>':
-        output += "&gt;";
-        break;
-      case '"':
-        output += "&quot;";
-        break;
-      case '\'':
-        output += "&#39;";
-        break;
-      default:
-        output += c;
-        break;
-    }
-  }
-  return output;
-}
-
 }  // namespace
 
 // File listing page template - now using generated headers:
@@ -64,15 +31,25 @@ void CrossPointWebServer::begin() {
     return;
   }
 
-  if (WiFi.status() != WL_CONNECTED) {
+  // Check if we have a valid network connection (either STA connected or AP mode)
-    Serial.printf("[%lu] [WEB] Cannot start webserver - WiFi not connected\n", millis());
+  const wifi_mode_t wifiMode = WiFi.getMode();
+  const bool isStaConnected = (wifiMode & WIFI_MODE_STA) && (WiFi.status() == WL_CONNECTED);
+  const bool isInApMode = (wifiMode & WIFI_MODE_AP) && (WiFi.softAPgetStationNum() >= 0);  // AP is running
+
+  if (!isStaConnected && !isInApMode) {
+    Serial.printf("[%lu] [WEB] Cannot start webserver - no valid network (mode=%d, status=%d)\n", millis(), wifiMode,
+                  WiFi.status());
     return;
   }
 
+  // Store AP mode flag for later use (e.g., in handleStatus)
+  apMode = isInApMode;
+
   Serial.printf("[%lu] [WEB] [MEM] Free heap before begin: %d bytes\n", millis(), ESP.getFreeHeap());
+  Serial.printf("[%lu] [WEB] Network mode: %s\n", millis(), apMode ? "AP" : "STA");
 
   Serial.printf("[%lu] [WEB] Creating web server on port %d...\n", millis(), port);
-  server = new WebServer(port);
+  server.reset(new WebServer(port));
   Serial.printf("[%lu] [WEB] [MEM] Free heap after WebServer allocation: %d bytes\n", millis(), ESP.getFreeHeap());
 
   if (!server) {
@@ -82,33 +59,38 @@ void CrossPointWebServer::begin() {
 
   // Setup routes
   Serial.printf("[%lu] [WEB] Setting up routes...\n", millis());
-  server->on("/", HTTP_GET, [this]() { handleRoot(); });
+  server->on("/", HTTP_GET, [this] { handleRoot(); });
-  server->on("/status", HTTP_GET, [this]() { handleStatus(); });
+  server->on("/files", HTTP_GET, [this] { handleFileList(); });
-  server->on("/files", HTTP_GET, [this]() { handleFileList(); });
+
+  server->on("/api/status", HTTP_GET, [this] { handleStatus(); });
+  server->on("/api/files", HTTP_GET, [this] { handleFileListData(); });
 
   // Upload endpoint with special handling for multipart form data
-  server->on("/upload", HTTP_POST, [this]() { handleUploadPost(); }, [this]() { handleUpload(); });
+  server->on("/upload", HTTP_POST, [this] { handleUploadPost(); }, [this] { handleUpload(); });
 
   // Create folder endpoint
-  server->on("/mkdir", HTTP_POST, [this]() { handleCreateFolder(); });
+  server->on("/mkdir", HTTP_POST, [this] { handleCreateFolder(); });
 
   // Delete file/folder endpoint
-  server->on("/delete", HTTP_POST, [this]() { handleDelete(); });
+  server->on("/delete", HTTP_POST, [this] { handleDelete(); });
 
-  server->onNotFound([this]() { handleNotFound(); });
+  server->onNotFound([this] { handleNotFound(); });
   Serial.printf("[%lu] [WEB] [MEM] Free heap after route setup: %d bytes\n", millis(), ESP.getFreeHeap());
 
   server->begin();
   running = true;
 
   Serial.printf("[%lu] [WEB] Web server started on port %d\n", millis(), port);
-  Serial.printf("[%lu] [WEB] Access at http://%s/\n", millis(), WiFi.localIP().toString().c_str());
+  // Show the correct IP based on network mode
+  const String ipAddr = apMode ? WiFi.softAPIP().toString() : WiFi.localIP().toString();
+  Serial.printf("[%lu] [WEB] Access at http://%s/\n", millis(), ipAddr.c_str());
   Serial.printf("[%lu] [WEB] [MEM] Free heap after server.begin(): %d bytes\n", millis(), ESP.getFreeHeap());
 }
 
 void CrossPointWebServer::stop() {
   if (!running || !server) {
-    Serial.printf("[%lu] [WEB] stop() called but already stopped (running=%d, server=%p)\n", millis(), running, server);
+    Serial.printf("[%lu] [WEB] stop() called but already stopped (running=%d, server=%p)\n", millis(), running,
+                  server.get());
     return;
   }
 
@@ -128,9 +110,7 @@ void CrossPointWebServer::stop() {
   delay(50);
   Serial.printf("[%lu] [WEB] Waited 50ms before deleting server\n", millis());
 
-  delete server;
+  server.reset();
-  server = nullptr;
-
   Serial.printf("[%lu] [WEB] Web server stopped and deleted\n", millis());
   Serial.printf("[%lu] [WEB] [MEM] Free heap after delete server: %d bytes\n", millis(), ESP.getFreeHeap());
 
@@ -139,7 +119,7 @@ void CrossPointWebServer::stop() {
   Serial.printf("[%lu] [WEB] [MEM] Free heap final: %d bytes\n", millis(), ESP.getFreeHeap());
 }
 
-void CrossPointWebServer::handleClient() {
+void CrossPointWebServer::handleClient() const {
   static unsigned long lastDebugPrint = 0;
 
   // Check running flag FIRST before accessing server
@@ -162,29 +142,26 @@ void CrossPointWebServer::handleClient() {
   server->handleClient();
 }
 
-void CrossPointWebServer::handleRoot() {
+void CrossPointWebServer::handleRoot() const {
-  String html = HomePageHtml;
+  server->send(200, "text/html", HomePageHtml);
-
-  // Replace placeholders with actual values
-  html.replace("%VERSION%", CROSSPOINT_VERSION);
-  html.replace("%IP_ADDRESS%", WiFi.localIP().toString());
-  html.replace("%FREE_HEAP%", String(ESP.getFreeHeap()));
-
-  server->send(200, "text/html", html);
   Serial.printf("[%lu] [WEB] Served root page\n", millis());
 }
 
-void CrossPointWebServer::handleNotFound() {
+void CrossPointWebServer::handleNotFound() const {
   String message = "404 Not Found\n\n";
   message += "URI: " + server->uri() + "\n";
   server->send(404, "text/plain", message);
 }
 
-void CrossPointWebServer::handleStatus() {
+void CrossPointWebServer::handleStatus() const {
+  // Get correct IP based on AP vs STA mode
+  const String ipAddr = apMode ? WiFi.softAPIP().toString() : WiFi.localIP().toString();
+
   String json = "{";
   json += "\"version\":\"" + String(CROSSPOINT_VERSION) + "\",";
-  json += "\"ip\":\"" + WiFi.localIP().toString() + "\",";
+  json += "\"ip\":\"" + ipAddr + "\",";
-  json += "\"rssi\":" + String(WiFi.RSSI()) + ",";
+  json += "\"mode\":\"" + String(apMode ? "AP" : "STA") + "\",";
+  json += "\"rssi\":" + String(apMode ? 0 : WiFi.RSSI()) + ",";  // RSSI not applicable in AP mode
   json += "\"freeHeap\":" + String(ESP.getFreeHeap()) + ",";
   json += "\"uptime\":" + String(millis() / 1000);
   json += "}";
@@ -192,26 +169,24 @@ void CrossPointWebServer::handleStatus() {
   server->send(200, "application/json", json);
 }
 
-std::vector<FileInfo> CrossPointWebServer::scanFiles(const char* path) {
+void CrossPointWebServer::scanFiles(const char* path, const std::function<void(FileInfo)>& callback) const {
-  std::vector<FileInfo> files;
-
   File root = SD.open(path);
   if (!root) {
     Serial.printf("[%lu] [WEB] Failed to open directory: %s\n", millis(), path);
-    return files;
+    return;
   }
 
   if (!root.isDirectory()) {
     Serial.printf("[%lu] [WEB] Not a directory: %s\n", millis(), path);
     root.close();
-    return files;
+    return;
   }
 
   Serial.printf("[%lu] [WEB] Scanning files in: %s\n", millis(), path);
 
   File file = root.openNextFile();
   while (file) {
-    String fileName = String(file.name());
+    auto fileName = String(file.name());
 
     // Skip hidden items (starting with ".")
     bool shouldHide = fileName.startsWith(".");
@@ -239,37 +214,24 @@ std::vector<FileInfo> CrossPointWebServer::scanFiles(const char* path) {
         info.isEpub = isEpubFile(info.name);
       }
 
-      files.push_back(info);
+      callback(info);
     }
 
     file.close();
     file = root.openNextFile();
   }
   root.close();
-
-  Serial.printf("[%lu] [WEB] Found %d items (files and folders)\n", millis(), files.size());
-  return files;
 }
 
-String CrossPointWebServer::formatFileSize(size_t bytes) {
+bool CrossPointWebServer::isEpubFile(const String& filename) const {
-  if (bytes < 1024) {
-    return String(bytes) + " B";
-  } else if (bytes < 1024 * 1024) {
-    return String(bytes / 1024.0, 1) + " KB";
-  } else {
-    return String(bytes / (1024.0 * 1024.0), 1) + " MB";
-  }
-}
-
-bool CrossPointWebServer::isEpubFile(const String& filename) {
   String lower = filename;
   lower.toLowerCase();
   return lower.endsWith(".epub");
 }
 
-void CrossPointWebServer::handleFileList() {
+void CrossPointWebServer::handleFileList() const { server->send(200, "text/html", FilesPageHtml); }
-  String html = FilesPageHeaderHtml;
 
+void CrossPointWebServer::handleFileListData() const {
   // Get current path from query string (default to root)
   String currentPath = "/";
   if (server->hasArg("path")) {
@@ -284,182 +246,35 @@ void CrossPointWebServer::handleFileList() {
     }
   }
 
-  // Get message from query string if present
+  server->setContentLength(CONTENT_LENGTH_UNKNOWN);
-  if (server->hasArg("msg")) {
+  server->send(200, "application/json", "");
-    String msg = escapeHtml(server->arg("msg"));
+  server->sendContent("[");
-    String msgType = server->hasArg("type") ? escapeHtml(server->arg("type")) : "success";
+  char output[512];
-    html += "<div class=\"message " + msgType + "\">" + msg + "</div>";
+  constexpr size_t outputSize = sizeof(output);
+  bool seenFirst = false;
+  scanFiles(currentPath.c_str(), [this, &output, seenFirst](const FileInfo& info) mutable {
+    JsonDocument doc;
+    doc["name"] = info.name;
+    doc["size"] = info.size;
+    doc["isDirectory"] = info.isDirectory;
+    doc["isEpub"] = info.isEpub;
+    const size_t written = serializeJson(doc, output, outputSize);
+    if (written >= outputSize) {
+      // JSON output truncated; skip this entry to avoid sending malformed JSON
+      Serial.printf("[%lu] [WEB] Skipping file entry with oversized JSON for name: %s\n", millis(), info.name.c_str());
+      return;
     }
 
-  // Hidden input to store current path for JavaScript
+    if (seenFirst) {
-  html += "<input type=\"hidden\" id=\"currentPath\" value=\"" + currentPath + "\">";
+      server->sendContent(",");
-
-  // Scan files in current path first (we need counts for the header)
-  std::vector<FileInfo> files = scanFiles(currentPath.c_str());
-
-  // Count items
-  int epubCount = 0;
-  int folderCount = 0;
-  size_t totalSize = 0;
-  for (const auto& file : files) {
-    if (file.isDirectory) {
-      folderCount++;
     } else {
-      if (file.isEpub) epubCount++;
+      seenFirst = true;
-      totalSize += file.size;
     }
-  }
+    server->sendContent(output);
-
-  // Page header with inline breadcrumb and action buttons
-  html += "<div class=\"page-header\">";
-  html += "<div class=\"page-header-left\">";
-  html += "<h1>📁 File Manager</h1>";
-
-  // Inline breadcrumb
-  html += "<div class=\"breadcrumb-inline\">";
-  html += "<span class=\"sep\">/</span>";
-
-  if (currentPath == "/") {
-    html += "<span class=\"current\">🏠</span>";
-  } else {
-    html += "<a href=\"/files\">🏠</a>";
-    String pathParts = currentPath.substring(1);  // Remove leading /
-    String buildPath = "";
-    int start = 0;
-    int end = pathParts.indexOf('/');
-
-    while (start < (int)pathParts.length()) {
-      String part;
-      if (end == -1) {
-        part = pathParts.substring(start);
-        buildPath += "/" + part;
-        html += "<span class=\"sep\">/</span><span class=\"current\">" + escapeHtml(part) + "</span>";
-        break;
-      } else {
-        part = pathParts.substring(start, end);
-        buildPath += "/" + part;
-        html += "<span class=\"sep\">/</span><a href=\"/files?path=" + buildPath + "\">" + escapeHtml(part) + "</a>";
-        start = end + 1;
-        end = pathParts.indexOf('/', start);
-      }
-    }
-  }
-  html += "</div>";
-  html += "</div>";
-
-  // Action buttons
-  html += "<div class=\"action-buttons\">";
-  html += "<button class=\"action-btn upload-action-btn\" onclick=\"openUploadModal()\">";
-  html += "📤 Upload";
-  html += "</button>";
-  html += "<button class=\"action-btn folder-action-btn\" onclick=\"openFolderModal()\">";
-  html += "📁 New Folder";
-  html += "</button>";
-  html += "</div>";
-
-  html += "</div>";  // end page-header
-
-  // Contents card with inline summary
-  html += "<div class=\"card\">";
-
-  // Contents header with inline stats
-  html += "<div class=\"contents-header\">";
-  html += "<h2 class=\"contents-title\">Contents</h2>";
-  html += "<span class=\"summary-inline\">";
-  html += String(folderCount) + " folder" + (folderCount != 1 ? "s" : "") + ", ";
-  html += String(files.size() - folderCount) + " file" + ((files.size() - folderCount) != 1 ? "s" : "") + ", ";
-  html += formatFileSize(totalSize);
-  html += "</span>";
-  html += "</div>";
-
-  if (files.empty()) {
-    html += "<div class=\"no-files\">This folder is empty</div>";
-  } else {
-    html += "<table class=\"file-table\">";
-    html += "<tr><th>Name</th><th>Type</th><th>Size</th><th class=\"actions-col\">Actions</th></tr>";
-
-    // Sort files: folders first, then epub files, then other files, alphabetically within each group
-    std::sort(files.begin(), files.end(), [](const FileInfo& a, const FileInfo& b) {
-      // Folders come first
-      if (a.isDirectory != b.isDirectory) return a.isDirectory > b.isDirectory;
-      // Then sort by epub status (epubs first among files)
-      if (!a.isDirectory && !b.isDirectory) {
-        if (a.isEpub != b.isEpub) return a.isEpub > b.isEpub;
-      }
-      // Then alphabetically
-      return a.name < b.name;
   });
-
+  server->sendContent("]");
-    for (const auto& file : files) {
+  // End of streamed response, empty chunk to signal client
-      String rowClass;
+  server->sendContent("");
-      String icon;
-      String badge;
-      String typeStr;
-      String sizeStr;
-
-      if (file.isDirectory) {
-        rowClass = "folder-row";
-        icon = "📁";
-        badge = "<span class=\"folder-badge\">FOLDER</span>";
-        typeStr = "Folder";
-        sizeStr = "-";
-
-        // Build the path to this folder
-        String folderPath = currentPath;
-        if (!folderPath.endsWith("/")) folderPath += "/";
-        folderPath += file.name;
-
-        html += "<tr class=\"" + rowClass + "\">";
-        html += "<td><span class=\"file-icon\">" + icon + "</span>";
-        html += "<a href=\"/files?path=" + folderPath + "\" class=\"folder-link\">" + escapeHtml(file.name) + "</a>" +
-                badge + "</td>";
-        html += "<td>" + typeStr + "</td>";
-        html += "<td>" + sizeStr + "</td>";
-        // Escape quotes for JavaScript string
-        String escapedName = file.name;
-        escapedName.replace("'", "\\'");
-        String escapedPath = folderPath;
-        escapedPath.replace("'", "\\'");
-        html += "<td class=\"actions-col\"><button class=\"delete-btn\" onclick=\"openDeleteModal('" + escapedName +
-                "', '" + escapedPath + "', true)\" title=\"Delete folder\">🗑️</button></td>";
-        html += "</tr>";
-      } else {
-        rowClass = file.isEpub ? "epub-file" : "";
-        icon = file.isEpub ? "📗" : "📄";
-        badge = file.isEpub ? "<span class=\"epub-badge\">EPUB</span>" : "";
-        String ext = file.name.substring(file.name.lastIndexOf('.') + 1);
-        ext.toUpperCase();
-        typeStr = ext;
-        sizeStr = formatFileSize(file.size);
-
-        // Build file path for delete
-        String filePath = currentPath;
-        if (!filePath.endsWith("/")) filePath += "/";
-        filePath += file.name;
-
-        html += "<tr class=\"" + rowClass + "\">";
-        html += "<td><span class=\"file-icon\">" + icon + "</span>" + escapeHtml(file.name) + badge + "</td>";
-        html += "<td>" + typeStr + "</td>";
-        html += "<td>" + sizeStr + "</td>";
-        // Escape quotes for JavaScript string
-        String escapedName = file.name;
-        escapedName.replace("'", "\\'");
-        String escapedPath = filePath;
-        escapedPath.replace("'", "\\'");
-        html += "<td class=\"actions-col\"><button class=\"delete-btn\" onclick=\"openDeleteModal('" + escapedName +
-                "', '" + escapedPath + "', false)\" title=\"Delete file\">🗑️</button></td>";
-        html += "</tr>";
-      }
-    }
-
-    html += "</table>";
-  }
-
-  html += "</div>";
-
-  html += FilesPageFooterHtml;
-
-  server->send(200, "text/html", html);
   Serial.printf("[%lu] [WEB] Served file listing page for path: %s\n", millis(), currentPath.c_str());
 }
 
@@ -471,7 +286,7 @@ static size_t uploadSize = 0;
 static bool uploadSuccess = false;
 static String uploadError = "";
 
-void CrossPointWebServer::handleUpload() {
+void CrossPointWebServer::handleUpload() const {
   static unsigned long lastWriteTime = 0;
   static unsigned long uploadStartTime = 0;
   static size_t lastLoggedSize = 0;
@@ -482,7 +297,7 @@ void CrossPointWebServer::handleUpload() {
     return;
   }
 
-  HTTPUpload& upload = server->upload();
+  const HTTPUpload& upload = server->upload();
 
   if (upload.status == UPLOAD_FILE_START) {
     uploadFileName = upload.filename;
@@ -513,13 +328,6 @@ void CrossPointWebServer::handleUpload() {
     Serial.printf("[%lu] [WEB] [UPLOAD] START: %s to path: %s\n", millis(), uploadFileName.c_str(), uploadPath.c_str());
     Serial.printf("[%lu] [WEB] [UPLOAD] Free heap: %d bytes\n", millis(), ESP.getFreeHeap());
 
-    // Validate file extension
-    if (!isEpubFile(uploadFileName)) {
-      uploadError = "Only .epub files are allowed";
-      Serial.printf("[%lu] [WEB] [UPLOAD] REJECTED - not an epub file\n", millis());
-      return;
-    }
-
     // Create file path
     String filePath = uploadPath;
     if (!filePath.endsWith("/")) filePath += "/";
@@ -532,8 +340,7 @@ void CrossPointWebServer::handleUpload() {
     }
 
     // Open file for writing
-    uploadFile = SD.open(filePath.c_str(), FILE_WRITE);
+    if (!FsHelpers::openFileForWrite("WEB", filePath, uploadFile)) {
-    if (!uploadFile) {
       uploadError = "Failed to create file on SD card";
       Serial.printf("[%lu] [WEB] [UPLOAD] FAILED to create file: %s\n", millis(), filePath.c_str());
       return;
@@ -542,10 +349,10 @@ void CrossPointWebServer::handleUpload() {
     Serial.printf("[%lu] [WEB] [UPLOAD] File created successfully: %s\n", millis(), filePath.c_str());
   } else if (upload.status == UPLOAD_FILE_WRITE) {
     if (uploadFile && uploadError.isEmpty()) {
-      unsigned long writeStartTime = millis();
+      const unsigned long writeStartTime = millis();
-      size_t written = uploadFile.write(upload.buf, upload.currentSize);
+      const size_t written = uploadFile.write(upload.buf, upload.currentSize);
-      unsigned long writeEndTime = millis();
+      const unsigned long writeEndTime = millis();
-      unsigned long writeDuration = writeEndTime - writeStartTime;
+      const unsigned long writeDuration = writeEndTime - writeStartTime;
 
       if (written != upload.currentSize) {
         uploadError = "Failed to write to SD card - disk may be full";
@@ -557,9 +364,9 @@ void CrossPointWebServer::handleUpload() {
 
         // Log progress every 50KB or if write took >100ms
         if (uploadSize - lastLoggedSize >= 51200 || writeDuration > 100) {
-          unsigned long timeSinceStart = millis() - uploadStartTime;
+          const unsigned long timeSinceStart = millis() - uploadStartTime;
-          unsigned long timeSinceLastWrite = millis() - lastWriteTime;
+          const unsigned long timeSinceLastWrite = millis() - lastWriteTime;
-          float kbps = (uploadSize / 1024.0) / (timeSinceStart / 1000.0);
+          const float kbps = (uploadSize / 1024.0) / (timeSinceStart / 1000.0);
 
           Serial.printf(
               "[%lu] [WEB] [UPLOAD] Progress: %d bytes (%.1f KB), %.1f KB/s, write took %lu ms, gap since last: %lu "
@@ -593,23 +400,23 @@ void CrossPointWebServer::handleUpload() {
   }
 }
 
-void CrossPointWebServer::handleUploadPost() {
+void CrossPointWebServer::handleUploadPost() const {
   if (uploadSuccess) {
     server->send(200, "text/plain", "File uploaded successfully: " + uploadFileName);
   } else {
-    String error = uploadError.isEmpty() ? "Unknown error during upload" : uploadError;
+    const String error = uploadError.isEmpty() ? "Unknown error during upload" : uploadError;
     server->send(400, "text/plain", error);
   }
 }
 
-void CrossPointWebServer::handleCreateFolder() {
+void CrossPointWebServer::handleCreateFolder() const {
   // Get folder name from form data
   if (!server->hasArg("name")) {
     server->send(400, "text/plain", "Missing folder name");
     return;
   }
 
-  String folderName = server->arg("name");
+  const String folderName = server->arg("name");
 
   // Validate folder name
   if (folderName.isEmpty()) {
@@ -652,7 +459,7 @@ void CrossPointWebServer::handleCreateFolder() {
   }
 }
 
-void CrossPointWebServer::handleDelete() {
+void CrossPointWebServer::handleDelete() const {
   // Get path from form data
   if (!server->hasArg("path")) {
     server->send(400, "text/plain", "Missing path");
@@ -660,7 +467,7 @@ void CrossPointWebServer::handleDelete() {
   }
 
   String itemPath = server->arg("path");
-  String itemType = server->hasArg("type") ? server->arg("type") : "file";
+  const String itemType = server->hasArg("type") ? server->arg("type") : "file";
 
   // Validate path
   if (itemPath.isEmpty() || itemPath == "/") {
@@ -674,7 +481,7 @@ void CrossPointWebServer::handleDelete() {
   }
 
   // Security check: prevent deletion of protected items
-  String itemName = itemPath.substring(itemPath.lastIndexOf('/') + 1);
+  const String itemName = itemPath.substring(itemPath.lastIndexOf('/') + 1);
 
   // Check if item starts with a dot (hidden/system file)
   if (itemName.startsWith(".")) {

src/network/CrossPointWebServer.h

@@ -2,8 +2,6 @@
 
 #include <WebServer.h>
 
-#include <functional>
-#include <string>
 #include <vector>
 
 // Structure to hold file information
@@ -26,7 +24,7 @@ class CrossPointWebServer {
   void stop();
 
   // Call this periodically to handle client requests
-  void handleClient();
+  void handleClient() const;
 
   // Check if server is running
   bool isRunning() const { return running; }
@@ -35,22 +33,24 @@ class CrossPointWebServer {
   uint16_t getPort() const { return port; }
 
  private:
-  WebServer* server = nullptr;
+  std::unique_ptr<WebServer> server = nullptr;
   bool running = false;
+  bool apMode = false;  // true when running in AP mode, false for STA mode
   uint16_t port = 80;
 
   // File scanning
-  std::vector<FileInfo> scanFiles(const char* path = "/");
+  void scanFiles(const char* path, const std::function<void(FileInfo)>& callback) const;
-  String formatFileSize(size_t bytes);
+  String formatFileSize(size_t bytes) const;
-  bool isEpubFile(const String& filename);
+  bool isEpubFile(const String& filename) const;
 
   // Request handlers
-  void handleRoot();
+  void handleRoot() const;
-  void handleNotFound();
+  void handleNotFound() const;
-  void handleStatus();
+  void handleStatus() const;
-  void handleFileList();
+  void handleFileList() const;
-  void handleUpload();
+  void handleFileListData() const;
-  void handleUploadPost();
+  void handleUpload() const;
-  void handleCreateFolder();
+  void handleUploadPost() const;
-  void handleDelete();
+  void handleCreateFolder() const;
+  void handleDelete() const;
 };

src/network/OtaUpdater.cpp

@@ -0,0 +1,169 @@
+#include "OtaUpdater.h"
+
+#include <ArduinoJson.h>
+#include <HTTPClient.h>
+#include <Update.h>
+#include <WiFiClientSecure.h>
+
+namespace {
+constexpr char latestReleaseUrl[] = "https://api.github.com/repos/daveallie/crosspoint-reader/releases/latest";
+}
+
+OtaUpdater::OtaUpdaterError OtaUpdater::checkForUpdate() {
+  const std::unique_ptr<WiFiClientSecure> client(new WiFiClientSecure);
+  client->setInsecure();
+  HTTPClient http;
+
+  Serial.printf("[%lu] [OTA] Fetching: %s\n", millis(), latestReleaseUrl);
+
+  http.begin(*client, latestReleaseUrl);
+  http.addHeader("User-Agent", "CrossPoint-ESP32-" CROSSPOINT_VERSION);
+
+  const int httpCode = http.GET();
+  if (httpCode != HTTP_CODE_OK) {
+    Serial.printf("[%lu] [OTA] HTTP error: %d\n", millis(), httpCode);
+    http.end();
+    return HTTP_ERROR;
+  }
+
+  JsonDocument doc;
+  const DeserializationError error = deserializeJson(doc, *client);
+  http.end();
+  if (error) {
+    Serial.printf("[%lu] [OTA] JSON parse failed: %s\n", millis(), error.c_str());
+    return JSON_PARSE_ERROR;
+  }
+
+  if (!doc["tag_name"].is<std::string>()) {
+    Serial.printf("[%lu] [OTA] No tag_name found\n", millis());
+    return JSON_PARSE_ERROR;
+  }
+  if (!doc["assets"].is<JsonArray>()) {
+    Serial.printf("[%lu] [OTA] No assets found\n", millis());
+    return JSON_PARSE_ERROR;
+  }
+
+  latestVersion = doc["tag_name"].as<std::string>();
+
+  for (int i = 0; i < doc["assets"].size(); i++) {
+    if (doc["assets"][i]["name"] == "firmware.bin") {
+      otaUrl = doc["assets"][i]["browser_download_url"].as<std::string>();
+      otaSize = doc["assets"][i]["size"].as<size_t>();
+      totalSize = otaSize;
+      updateAvailable = true;
+      break;
+    }
+  }
+
+  if (!updateAvailable) {
+    Serial.printf("[%lu] [OTA] No firmware.bin asset found\n", millis());
+    return NO_UPDATE;
+  }
+
+  Serial.printf("[%lu] [OTA] Found update: %s\n", millis(), latestVersion.c_str());
+  return OK;
+}
+
+bool OtaUpdater::isUpdateNewer() {
+  if (!updateAvailable || latestVersion.empty() || latestVersion == CROSSPOINT_VERSION) {
+    return false;
+  }
+
+  // semantic version check (only match on 3 segments)
+  const auto updateMajor = stoi(latestVersion.substr(0, latestVersion.find('.')));
+  const auto updateMinor = stoi(
+      latestVersion.substr(latestVersion.find('.') + 1, latestVersion.find_last_of('.') - latestVersion.find('.') - 1));
+  const auto updatePatch = stoi(latestVersion.substr(latestVersion.find_last_of('.') + 1));
+
+  std::string currentVersion = CROSSPOINT_VERSION;
+  const auto currentMajor = stoi(currentVersion.substr(0, currentVersion.find('.')));
+  const auto currentMinor = stoi(currentVersion.substr(
+      currentVersion.find('.') + 1, currentVersion.find_last_of('.') - currentVersion.find('.') - 1));
+  const auto currentPatch = stoi(currentVersion.substr(currentVersion.find_last_of('.') + 1));
+
+  if (updateMajor > currentMajor) {
+    return true;
+  }
+  if (updateMajor < currentMajor) {
+    return false;
+  }
+
+  if (updateMinor > currentMinor) {
+    return true;
+  }
+  if (updateMinor < currentMinor) {
+    return false;
+  }
+
+  if (updatePatch > currentPatch) {
+    return true;
+  }
+  return false;
+}
+
+const std::string& OtaUpdater::getLatestVersion() { return latestVersion; }
+
+OtaUpdater::OtaUpdaterError OtaUpdater::installUpdate(const std::function<void(size_t, size_t)>& onProgress) {
+  if (!isUpdateNewer()) {
+    return UPDATE_OLDER_ERROR;
+  }
+
+  const std::unique_ptr<WiFiClientSecure> client(new WiFiClientSecure);
+  client->setInsecure();
+  HTTPClient http;
+
+  Serial.printf("[%lu] [OTA] Fetching: %s\n", millis(), otaUrl.c_str());
+
+  http.begin(*client, otaUrl.c_str());
+  http.setFollowRedirects(HTTPC_STRICT_FOLLOW_REDIRECTS);
+  http.addHeader("User-Agent", "CrossPoint-ESP32-" CROSSPOINT_VERSION);
+  const int httpCode = http.GET();
+
+  if (httpCode != HTTP_CODE_OK) {
+    Serial.printf("[%lu] [OTA] Download failed: %d\n", millis(), httpCode);
+    http.end();
+    return HTTP_ERROR;
+  }
+
+  // 2. Get length and stream
+  const size_t contentLength = http.getSize();
+
+  if (contentLength != otaSize) {
+    Serial.printf("[%lu] [OTA] Invalid content length\n", millis());
+    http.end();
+    return HTTP_ERROR;
+  }
+
+  // 3. Begin the ESP-IDF Update process
+  if (!Update.begin(otaSize)) {
+    Serial.printf("[%lu] [OTA] Not enough space. Error: %s\n", millis(), Update.errorString());
+    http.end();
+    return INTERNAL_UPDATE_ERROR;
+  }
+
+  this->totalSize = otaSize;
+  Serial.printf("[%lu] [OTA] Update started\n", millis());
+  Update.onProgress([this, onProgress](const size_t progress, const size_t total) {
+    this->processedSize = progress;
+    this->totalSize = total;
+    onProgress(progress, total);
+  });
+  const size_t written = Update.writeStream(*client);
+  http.end();
+
+  if (written == otaSize) {
+    Serial.printf("[%lu] [OTA] Successfully written %u bytes\n", millis(), written);
+  } else {
+    Serial.printf("[%lu] [OTA] Written only %u/%u bytes. Error: %s\n", millis(), written, otaSize,
+                  Update.errorString());
+    return INTERNAL_UPDATE_ERROR;
+  }
+
+  if (Update.end() && Update.isFinished()) {
+    Serial.printf("[%lu] [OTA] Update complete\n", millis());
+    return OK;
+  } else {
+    Serial.printf("[%lu] [OTA] Error Occurred: %s\n", millis(), Update.errorString());
+    return INTERNAL_UPDATE_ERROR;
+  }
+}

src/network/OtaUpdater.h

@@ -0,0 +1,30 @@
+#pragma once
+
+#include <functional>
+#include <string>
+
+class OtaUpdater {
+  bool updateAvailable = false;
+  std::string latestVersion;
+  std::string otaUrl;
+  size_t otaSize = 0;
+
+ public:
+  enum OtaUpdaterError {
+    OK = 0,
+    NO_UPDATE,
+    HTTP_ERROR,
+    JSON_PARSE_ERROR,
+    UPDATE_OLDER_ERROR,
+    INTERNAL_UPDATE_ERROR,
+    OOM_ERROR,
+  };
+  size_t processedSize = 0;
+  size_t totalSize = 0;
+
+  OtaUpdater() = default;
+  bool isUpdateNewer();
+  const std::string& getLatestVersion();
+  OtaUpdaterError checkForUpdate();
+  OtaUpdaterError installUpdate(const std::function<void(size_t, size_t)>& onProgress);
+};

src/network/html/FilesPage.html

@@ -0,0 +1,859 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <meta charset="UTF-8" />
+  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+  <title>CrossPoint Reader - Files</title>
+  <style>
+    body {
+      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
+      Oxygen, Ubuntu, sans-serif;
+      max-width: 800px;
+      margin: 0 auto;
+      padding: 20px;
+      background-color: #f5f5f5;
+      color: #333;
+    }
+    h1 {
+      color: #2c3e50;
+      margin-bottom: 5px;
+    }
+    h2 {
+      color: #34495e;
+      margin-top: 0;
+    }
+    .card {
+      background: white;
+      border-radius: 8px;
+      padding: 20px;
+      margin: 15px 0;
+      box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
+    }
+    .page-header {
+      display: flex;
+      justify-content: space-between;
+      align-items: center;
+      flex-wrap: wrap;
+      gap: 15px;
+      margin-bottom: 20px;
+      padding-bottom: 15px;
+      border-bottom: 2px solid #3498db;
+    }
+    .page-header-left {
+      display: flex;
+      align-items: baseline;
+      gap: 12px;
+      flex-wrap: wrap;
+    }
+    .breadcrumb-inline {
+      color: #7f8c8d;
+      font-size: 1.1em;
+    }
+    .breadcrumb-inline a {
+      color: #3498db;
+      text-decoration: none;
+    }
+    .breadcrumb-inline a:hover {
+      text-decoration: underline;
+    }
+    .breadcrumb-inline .sep {
+      margin: 0 6px;
+      color: #bdc3c7;
+    }
+    .breadcrumb-inline .current {
+      color: #2c3e50;
+      font-weight: 500;
+    }
+    .nav-links {
+      margin: 20px 0;
+    }
+    .nav-links a {
+      display: inline-block;
+      padding: 10px 20px;
+      background-color: #3498db;
+      color: white;
+      text-decoration: none;
+      border-radius: 4px;
+      margin-right: 10px;
+    }
+    .nav-links a:hover {
+      background-color: #2980b9;
+    }
+    /* Action buttons */
+    .action-buttons {
+      display: flex;
+      gap: 10px;
+    }
+    .action-btn {
+      color: white;
+      padding: 10px 16px;
+      border: none;
+      border-radius: 4px;
+      cursor: pointer;
+      font-size: 0.95em;
+      font-weight: 600;
+      display: flex;
+      align-items: center;
+      gap: 6px;
+    }
+    .upload-action-btn {
+      background-color: #27ae60;
+    }
+    .upload-action-btn:hover {
+      background-color: #219a52;
+    }
+    .folder-action-btn {
+      background-color: #f39c12;
+    }
+    .folder-action-btn:hover {
+      background-color: #d68910;
+    }
+    /* Upload modal */
+    .modal-overlay {
+      display: none;
+      position: fixed;
+      top: 0;
+      left: 0;
+      right: 0;
+      bottom: 0;
+      background: rgba(0, 0, 0, 0.5);
+      z-index: 200;
+      justify-content: center;
+      align-items: center;
+    }
+    .modal-overlay.open {
+      display: flex;
+    }
+    .modal {
+      background: white;
+      border-radius: 8px;
+      padding: 25px;
+      max-width: 450px;
+      width: 90%;
+      box-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
+    }
+    .modal h3 {
+      margin: 0 0 15px 0;
+      color: #2c3e50;
+    }
+    .modal-close {
+      float: right;
+      background: none;
+      border: none;
+      font-size: 1.5em;
+      cursor: pointer;
+      color: #7f8c8d;
+      line-height: 1;
+    }
+    .modal-close:hover {
+      color: #2c3e50;
+    }
+    .file-table {
+      width: 100%;
+      border-collapse: collapse;
+    }
+    .file-table th,
+    .file-table td {
+      padding: 12px;
+      text-align: left;
+      border-bottom: 1px solid #eee;
+    }
+    .file-table th {
+      background-color: #f8f9fa;
+      font-weight: 600;
+      color: #7f8c8d;
+    }
+    .file-table tr:hover {
+      background-color: #f8f9fa;
+    }
+    .epub-file {
+      background-color: #e8f6e9 !important;
+    }
+    .epub-file:hover {
+      background-color: #d4edda !important;
+    }
+    .folder-row {
+      background-color: #fff9e6 !important;
+    }
+    .folder-row:hover {
+      background-color: #fff3cd !important;
+    }
+    .epub-badge {
+      display: inline-block;
+      padding: 2px 8px;
+      background-color: #27ae60;
+      color: white;
+      border-radius: 10px;
+      font-size: 0.75em;
+      margin-left: 8px;
+    }
+    .folder-badge {
+      display: inline-block;
+      padding: 2px 8px;
+      background-color: #f39c12;
+      color: white;
+      border-radius: 10px;
+      font-size: 0.75em;
+      margin-left: 8px;
+    }
+    .file-icon {
+      margin-right: 8px;
+    }
+    .folder-link {
+      color: #2c3e50;
+      text-decoration: none;
+      cursor: pointer;
+    }
+    .folder-link:hover {
+      color: #3498db;
+      text-decoration: underline;
+    }
+    .upload-form {
+      margin-top: 10px;
+    }
+    .upload-form input[type="file"] {
+      margin: 10px 0;
+      width: 100%;
+    }
+    .upload-btn {
+      background-color: #27ae60;
+      color: white;
+      padding: 10px 20px;
+      border: none;
+      border-radius: 4px;
+      cursor: pointer;
+      font-size: 1em;
+      width: 100%;
+    }
+    .upload-btn:hover {
+      background-color: #219a52;
+    }
+    .upload-btn:disabled {
+      background-color: #95a5a6;
+      cursor: not-allowed;
+    }
+    .file-info {
+      color: #7f8c8d;
+      font-size: 0.85em;
+      margin: 8px 0;
+    }
+    .no-files {
+      text-align: center;
+      color: #95a5a6;
+      padding: 40px;
+      font-style: italic;
+    }
+    .message {
+      padding: 15px;
+      border-radius: 4px;
+      margin: 15px 0;
+    }
+    .message.success {
+      background-color: #d4edda;
+      color: #155724;
+      border: 1px solid #c3e6cb;
+    }
+    .message.error {
+      background-color: #f8d7da;
+      color: #721c24;
+      border: 1px solid #f5c6cb;
+    }
+    .contents-header {
+      display: flex;
+      justify-content: space-between;
+      align-items: center;
+      margin-bottom: 12px;
+    }
+    .contents-title {
+      font-size: 1.1em;
+      font-weight: 600;
+      color: #34495e;
+      margin: 0;
+    }
+    .summary-inline {
+      color: #7f8c8d;
+      font-size: 0.9em;
+    }
+    #progress-container {
+      display: none;
+      margin-top: 10px;
+    }
+    #progress-bar {
+      width: 100%;
+      height: 20px;
+      background-color: #e0e0e0;
+      border-radius: 10px;
+      overflow: hidden;
+    }
+    #progress-fill {
+      height: 100%;
+      background-color: #27ae60;
+      width: 0%;
+      transition: width 0.3s;
+    }
+    #progress-text {
+      text-align: center;
+      margin-top: 5px;
+      font-size: 0.9em;
+      color: #7f8c8d;
+    }
+    .folder-form {
+      margin-top: 10px;
+    }
+    .folder-input {
+      width: 100%;
+      padding: 10px;
+      border: 1px solid #ddd;
+      border-radius: 4px;
+      font-size: 1em;
+      margin-bottom: 10px;
+      box-sizing: border-box;
+    }
+    .folder-btn {
+      background-color: #f39c12;
+      color: white;
+      padding: 10px 20px;
+      border: none;
+      border-radius: 4px;
+      cursor: pointer;
+      font-size: 1em;
+      width: 100%;
+    }
+    .folder-btn:hover {
+      background-color: #d68910;
+    }
+    /* Delete button styles */
+    .delete-btn {
+      background: none;
+      border: none;
+      cursor: pointer;
+      font-size: 1.1em;
+      padding: 4px 8px;
+      border-radius: 4px;
+      color: #95a5a6;
+      transition: all 0.15s;
+    }
+    .delete-btn:hover {
+      background-color: #fee;
+      color: #e74c3c;
+    }
+    .actions-col {
+      width: 60px;
+      text-align: center;
+    }
+    /* Delete modal */
+    .delete-warning {
+      color: #e74c3c;
+      font-weight: 600;
+      margin: 10px 0;
+    }
+    .delete-item-name {
+      font-weight: 600;
+      color: #2c3e50;
+      word-break: break-all;
+    }
+    .delete-btn-confirm {
+      background-color: #e74c3c;
+      color: white;
+      padding: 10px 20px;
+      border: none;
+      border-radius: 4px;
+      cursor: pointer;
+      font-size: 1em;
+      width: 100%;
+    }
+    .delete-btn-confirm:hover {
+      background-color: #c0392b;
+    }
+    .delete-btn-cancel {
+      background-color: #95a5a6;
+      color: white;
+      padding: 10px 20px;
+      border: none;
+      border-radius: 4px;
+      cursor: pointer;
+      font-size: 1em;
+      width: 100%;
+      margin-top: 10px;
+    }
+    .delete-btn-cancel:hover {
+      background-color: #7f8c8d;
+    }
+    .loader-container {
+      display: flex;
+      justify-content: center;
+      align-items: center;
+      margin: 20px 0;
+    }
+    .loader {
+      width: 48px;
+      height: 48px;
+      border: 5px solid #AAA;
+      border-bottom-color: transparent;
+      border-radius: 50%;
+      display: inline-block;
+      box-sizing: border-box;
+      animation: rotation 1s linear infinite;
+    }
+    @keyframes rotation {
+      from {
+        transform: rotate(0deg);
+      }
+      to {
+        transform: rotate(360deg);
+      }
+    }
+    /* Mobile responsive styles */
+    @media (max-width: 600px) {
+      body {
+        padding: 10px;
+        font-size: 14px;
+      }
+      .card {
+        padding: 12px;
+        margin: 10px 0;
+      }
+      .page-header {
+        gap: 10px;
+        margin-bottom: 12px;
+        padding-bottom: 10px;
+      }
+      .page-header-left {
+        gap: 8px;
+      }
+      h1 {
+        font-size: 1.3em;
+      }
+      .breadcrumb-inline {
+        font-size: 0.95em;
+      }
+      .nav-links a {
+        padding: 8px 12px;
+        margin-right: 6px;
+        font-size: 0.9em;
+      }
+      .action-buttons {
+        gap: 6px;
+      }
+      .action-btn {
+        padding: 8px 10px;
+        font-size: 0.85em;
+      }
+      .file-table th,
+      .file-table td {
+        padding: 8px 6px;
+        font-size: 0.9em;
+      }
+      .file-table th {
+        font-size: 0.85em;
+      }
+      .file-icon {
+        margin-right: 4px;
+      }
+      .epub-badge,
+      .folder-badge {
+        padding: 2px 5px;
+        font-size: 0.65em;
+        margin-left: 4px;
+      }
+      .contents-header {
+        margin-bottom: 8px;
+        flex-wrap: wrap;
+        gap: 4px;
+      }
+      .contents-title {
+        font-size: 1em;
+      }
+      .summary-inline {
+        font-size: 0.8em;
+      }
+      .modal {
+        padding: 15px;
+      }
+      .modal h3 {
+        font-size: 1.1em;
+      }
+      .actions-col {
+        width: 40px;
+      }
+      .delete-btn {
+        font-size: 1em;
+        padding: 2px 4px;
+      }
+      .no-files {
+        padding: 20px;
+        font-size: 0.9em;
+      }
+    }
+  </style>
+</head>
+<body>
+<div class="nav-links">
+  <a href="/">Home</a>
+  <a href="/files">File Manager</a>
+</div>
+
+<div class="page-header">
+  <div class="page-header-left">
+    <h1>📁 File Manager</h1>
+    <div class="breadcrumb-inline" id="directory-breadcrumbs"></div>
+  </div>
+
+  <div class="action-buttons">
+    <button class="action-btn upload-action-btn" onclick="openUploadModal()">📤 Upload</button>
+    <button class="action-btn folder-action-btn" onclick="openFolderModal()">📁 New Folder</button>
+  </div>
+</div>
+
+<div class="card">
+  <div class="contents-header">
+    <h2 class="contents-title">Contents</h2>
+    <span class="summary-inline" id="folder-summary"></span>
+  </div>
+
+  <div id="file-table">
+    <div class="loader-container">
+      <span class="loader"></span>
+    </div>
+  </div>
+</div>
+
+<div class="card">
+  <p style="text-align: center; color: #95a5a6; margin: 0;">
+    CrossPoint E-Reader • Open Source
+  </p>
+</div>
+
+<!-- Upload Modal -->
+<div class="modal-overlay" id="uploadModal">
+  <div class="modal">
+    <button class="modal-close" onclick="closeUploadModal()">&times;</button>
+    <h3>📤 Upload file</h3>
+    <div class="upload-form">
+      <p class="file-info">Select a file to upload to <strong id="uploadPathDisplay"></strong></p>
+      <input type="file" id="fileInput" onchange="validateFile()">
+      <button id="uploadBtn" class="upload-btn" onclick="uploadFile()" disabled>Upload</button>
+      <div id="progress-container">
+        <div id="progress-bar"><div id="progress-fill"></div></div>
+        <div id="progress-text"></div>
+      </div>
+    </div>
+  </div>
+</div>
+
+<!-- New Folder Modal -->
+<div class="modal-overlay" id="folderModal">
+  <div class="modal">
+    <button class="modal-close" onclick="closeFolderModal()">&times;</button>
+    <h3>📁 New Folder</h3>
+    <div class="folder-form">
+      <p class="file-info">Create a new folder in <strong id="folderPathDisplay"></strong></p>
+      <input type="text" id="folderName" class="folder-input" placeholder="Folder name...">
+      <button class="folder-btn" onclick="createFolder()">Create Folder</button>
+    </div>
+  </div>
+</div>
+
+<!-- Delete Confirmation Modal -->
+<div class="modal-overlay" id="deleteModal">
+  <div class="modal">
+    <button class="modal-close" onclick="closeDeleteModal()">&times;</button>
+    <h3>🗑️ Delete Item</h3>
+    <div class="folder-form">
+      <p class="delete-warning">⚠️ This action cannot be undone!</p>
+      <p class="file-info">Are you sure you want to delete:</p>
+      <p class="delete-item-name" id="deleteItemName"></p>
+      <input type="hidden" id="deleteItemPath">
+      <input type="hidden" id="deleteItemType">
+      <button class="delete-btn-confirm" onclick="confirmDelete()">Delete</button>
+      <button class="delete-btn-cancel" onclick="closeDeleteModal()">Cancel</button>
+    </div>
+  </div>
+</div>
+
+<script>
+  // get current path from query parameter
+  const currentPath = decodeURIComponent(new URLSearchParams(window.location.search).get('path') || '/');
+
+  function escapeHtml(unsafe) {
+    return unsafe
+      .replaceAll("&", "&amp;")
+      .replaceAll("<", "&lt;")
+      .replaceAll(">", "&gt;")
+      .replaceAll('"', "&quot;")
+      .replaceAll("'", "&#039;");
+  }
+
+  function formatFileSize(bytes) {
+    if (bytes === 0) return '0 B';
+    const k = 1024;
+    const sizes = ['B', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];
+    const i = Math.floor(Math.log(bytes) / Math.log(k));
+    return parseFloat((bytes / Math.pow(k, i)).toFixed(2)).toLocaleString() + ' ' + sizes[i];
+  }
+
+  async function hydrate() {
+    // Close modals when clicking overlay
+    document.querySelectorAll('.modal-overlay').forEach(function(overlay) {
+      overlay.addEventListener('click', function(e) {
+        if (e.target === overlay) {
+          overlay.classList.remove('open');
+        }
+      });
+    });
+
+    const breadcrumbs = document.getElementById('directory-breadcrumbs');
+    const fileTable = document.getElementById('file-table');
+
+    let breadcrumbContent = '<span class="sep">/</span>';
+    if (currentPath === '/') {
+      breadcrumbContent += '<span class="current">🏠</span>';
+    } else {
+      breadcrumbContent += '<a href="/files">🏠</a>';
+      const pathSegments = currentPath.split('/');
+      pathSegments.slice(1, pathSegments.length - 1).forEach(function(segment, index) {
+        breadcrumbContent += '<span class="sep">/</span><a href="/files?path=' + encodeURIComponent(pathSegments.slice(0, index + 2).join('/')) + '">' + escapeHtml(segment) + '</a>';
+      });
+      breadcrumbContent += '<span class="sep">/</span>';
+      breadcrumbContent += '<span class="current">' + escapeHtml(pathSegments[pathSegments.length - 1]) + '</span>';
+    }
+    breadcrumbs.innerHTML = breadcrumbContent;
+
+    let files = [];
+    try {
+      const response = await fetch('/api/files?path=' + encodeURIComponent(currentPath));
+      if (!response.ok) {
+        throw new Error('Failed to load files: ' + response.status + ' ' + response.statusText);
+      }
+      files = await response.json();
+    } catch (e) {
+      console.error(e);
+      fileTable.innerHTML = '<div class="no-files">An error occurred while loading the files</div>';
+      return;
+    }
+
+    let folderCount = 0;
+    let totalSize = 0;
+    files.forEach(file => {
+      if (file.isDirectory) folderCount++;
+      totalSize += file.size;
+    });
+
+    document.getElementById('folder-summary').innerHTML = `${folderCount} folders, ${files.length - folderCount} files, ${formatFileSize(totalSize)}`;
+
+    if (files.length === 0) {
+      fileTable.innerHTML = '<div class="no-files">This folder is empty</div>';
+    } else {
+      let fileTableContent = '<table class="file-table">';
+      fileTableContent += '<tr><th>Name</th><th>Type</th><th>Size</th><th class="actions-col">Actions</th></tr>';
+
+      const sortedFiles = files.sort((a, b) => {
+        // Directories first, then epub files, then other files, alphabetically within each group
+        if (a.isDirectory && !b.isDirectory) return -1;
+        if (!a.isDirectory && b.isDirectory) return 1;
+        if (a.isEpub && !b.isEpub) return -1;
+        if (!a.isEpub && b.isEpub) return 1;
+        return a.name.localeCompare(b.name);
+      });
+
+      sortedFiles.forEach(file => {
+        if (file.isDirectory) {
+          let folderPath = currentPath;
+          if (!folderPath.endsWith("/")) folderPath += "/";
+          folderPath += file.name;
+
+          fileTableContent += '<tr class="folder-row">';
+          fileTableContent += `<td><span class="file-icon">📁</span><a href="/files?path=${encodeURIComponent(folderPath)}" class="folder-link">${escapeHtml(file.name)}</a><span class="folder-badge">FOLDER</span></td>`;
+          fileTableContent += '<td>Folder</td>';
+          fileTableContent += '<td>-</td>';
+          fileTableContent += `<td class="actions-col"><button class="delete-btn" onclick="openDeleteModal('${file.name.replaceAll("'", "\\'")}', '${folderPath.replaceAll("'", "\\'")}', true)" title="Delete folder">🗑️</button></td>`;
+          fileTableContent += '</tr>';
+        } else {
+          let filePath = currentPath;
+          if (!filePath.endsWith("/")) filePath += "/";
+          filePath += file.name;
+
+          fileTableContent += `<tr class="${file.isEpub ? 'epub-file' : ''}">`;
+          fileTableContent += `<td><span class="file-icon">${file.isEpub ? '📗' : '📄'}</span>${escapeHtml(file.name)}`;
+          if (file.isEpub) fileTableContent += '<span class="epub-badge">EPUB</span>';
+          fileTableContent += '</td>';
+          fileTableContent += `<td>${file.name.split('.').pop().toUpperCase()}</td>`;
+          fileTableContent += `<td>${formatFileSize(file.size)}</td>`;
+          fileTableContent += `<td class="actions-col"><button class="delete-btn" onclick="openDeleteModal('${file.name.replaceAll("'", "\\'")}', '${filePath.replaceAll("'", "\\'")}', false)" title="Delete file">🗑️</button></td>`;
+          fileTableContent += '</tr>';
+        }
+      });
+
+      fileTableContent += '</table>';
+      fileTable.innerHTML = fileTableContent;
+    }
+  }
+
+  // Modal functions
+  function openUploadModal() {
+    document.getElementById('uploadPathDisplay').textContent = currentPath === '/' ? '/ 🏠' : currentPath;
+    document.getElementById('uploadModal').classList.add('open');
+  }
+
+  function closeUploadModal() {
+    document.getElementById('uploadModal').classList.remove('open');
+    document.getElementById('fileInput').value = '';
+    document.getElementById('uploadBtn').disabled = true;
+    document.getElementById('progress-container').style.display = 'none';
+    document.getElementById('progress-fill').style.width = '0%';
+    document.getElementById('progress-fill').style.backgroundColor = '#27ae60';
+  }
+
+  function openFolderModal() {
+    document.getElementById('folderPathDisplay').textContent = currentPath === '/' ? '/ 🏠' : currentPath;
+    document.getElementById('folderModal').classList.add('open');
+    document.getElementById('folderName').value = '';
+  }
+
+  function closeFolderModal() {
+    document.getElementById('folderModal').classList.remove('open');
+  }
+
+  function validateFile() {
+    const fileInput = document.getElementById('fileInput');
+    const uploadBtn = document.getElementById('uploadBtn');
+    const file = fileInput.files[0];
+    uploadBtn.disabled = !file;
+  }
+
+  function uploadFile() {
+    const fileInput = document.getElementById('fileInput');
+    const file = fileInput.files[0];
+
+    if (!file) {
+      alert('Please select a file first!');
+      return;
+    }
+
+    const formData = new FormData();
+    formData.append('file', file);
+
+    const progressContainer = document.getElementById('progress-container');
+    const progressFill = document.getElementById('progress-fill');
+    const progressText = document.getElementById('progress-text');
+    const uploadBtn = document.getElementById('uploadBtn');
+
+    progressContainer.style.display = 'block';
+    uploadBtn.disabled = true;
+
+    const xhr = new XMLHttpRequest();
+    // Include path as query parameter since multipart form data doesn't make
+    // form fields available until after file upload completes
+    xhr.open('POST', '/upload?path=' + encodeURIComponent(currentPath), true);
+
+    xhr.upload.onprogress = function(e) {
+      if (e.lengthComputable) {
+        const percent = Math.round((e.loaded / e.total) * 100);
+        progressFill.style.width = percent + '%';
+        progressText.textContent = 'Uploading: ' + percent + '%';
+      }
+    };
+
+    xhr.onload = function() {
+      if (xhr.status === 200) {
+        progressText.textContent = 'Upload complete!';
+        setTimeout(function() {
+          window.location.reload();
+        }, 1000);
+      } else {
+        progressText.textContent = 'Upload failed: ' + xhr.responseText;
+        progressFill.style.backgroundColor = '#e74c3c';
+        uploadBtn.disabled = false;
+      }
+    };
+
+    xhr.onerror = function() {
+      progressText.textContent = 'Upload failed - network error';
+      progressFill.style.backgroundColor = '#e74c3c';
+      uploadBtn.disabled = false;
+    };
+
+    xhr.send(formData);
+  }
+
+  function createFolder() {
+    const folderName = document.getElementById('folderName').value.trim();
+
+    if (!folderName) {
+      alert('Please enter a folder name!');
+      return;
+    }
+
+    // Validate folder name (no special characters except underscore and hyphen)
+    const validName = /^[a-zA-Z0-9_\-]+$/.test(folderName);
+    if (!validName) {
+      alert('Folder name can only contain letters, numbers, underscores, and hyphens.');
+      return;
+    }
+
+    const formData = new FormData();
+    formData.append('name', folderName);
+    formData.append('path', currentPath);
+
+    const xhr = new XMLHttpRequest();
+    xhr.open('POST', '/mkdir', true);
+
+    xhr.onload = function() {
+      if (xhr.status === 200) {
+        window.location.reload();
+      } else {
+        alert('Failed to create folder: ' + xhr.responseText);
+      }
+    };
+
+    xhr.onerror = function() {
+      alert('Failed to create folder - network error');
+    };
+
+    xhr.send(formData);
+  }
+
+  // Delete functions
+  function openDeleteModal(name, path, isFolder) {
+    document.getElementById('deleteItemName').textContent = (isFolder ? '📁 ' : '📄 ') + name;
+    document.getElementById('deleteItemPath').value = path;
+    document.getElementById('deleteItemType').value = isFolder ? 'folder' : 'file';
+    document.getElementById('deleteModal').classList.add('open');
+  }
+
+  function closeDeleteModal() {
+    document.getElementById('deleteModal').classList.remove('open');
+  }
+
+  function confirmDelete() {
+    const path = document.getElementById('deleteItemPath').value;
+    const itemType = document.getElementById('deleteItemType').value;
+
+    const formData = new FormData();
+    formData.append('path', path);
+    formData.append('type', itemType);
+
+    const xhr = new XMLHttpRequest();
+    xhr.open('POST', '/delete', true);
+
+    xhr.onload = function() {
+      if (xhr.status === 200) {
+        window.location.reload();
+      } else {
+        alert('Failed to delete: ' + xhr.responseText);
+        closeDeleteModal();
+      }
+    };
+
+    xhr.onerror = function() {
+      alert('Failed to delete - network error');
+      closeDeleteModal();
+    };
+
+    xhr.send(formData);
+  }
+
+  hydrate();
+</script>
+</body>
+</html>

src/network/html/HomePage.html

@@ -83,7 +83,7 @@
       <h2>Device Status</h2>
       <div class="info-row">
         <span class="label">Version</span>
-        <span class="value">%VERSION%</span>
+        <span class="value" id="version"></span>
       </div>
       <div class="info-row">
         <span class="label">WiFi Status</span>
@@ -91,11 +91,11 @@
       </div>
       <div class="info-row">
         <span class="label">IP Address</span>
-        <span class="value">%IP_ADDRESS%</span>
+        <span class="value" id="ip-address"></span>
       </div>
       <div class="info-row">
         <span class="label">Free Memory</span>
-        <span class="value">%FREE_HEAP% bytes</span>
+        <span class="value" id="free-heap"></span>
       </div>
     </div>
 
@@ -104,5 +104,26 @@
         CrossPoint E-Reader • Open Source
       </p>
     </div>
+  <script>
+    async function fetchStatus() {
+      try {
+        const response = await fetch('/api/status');
+        if (!response.ok) {
+          throw new Error('Failed to fetch status: ' + response.status + ' ' + response.statusText);
+        }
+        const data = await response.json();
+        document.getElementById('version').textContent = data.version || 'N/A';
+        document.getElementById('ip-address').textContent = data.ip || 'N/A';
+        document.getElementById('free-heap').textContent = data.freeHeap
+          ? data.freeHeap.toLocaleString() + ' bytes'
+          : 'N/A';
+      } catch (error) {
+        console.error('Error fetching status:', error);
+      }
+    }
+
+    // Fetch status on page load
+    window.onload = fetchStatus;
+  </script>
   </body>
 </html>