Cut release 0.9.0

## Summary

* Use single unified cache file for book spine, table of contents, and
core metadata (title, author, cover image)
* Use new temp item store file in OPF parsing to store items to be
rescaned when parsing spine
  * This avoids us holding these items in memory
* Use new toc.bin.tmp and spine.bin.tmp to build out partial toc / spine
data as part of parsing content.opf and the NCX file
  * These files are re-read multiple times to ultimately build book.bin

## Additional Context

* Spec for file format included below as an image
* This should help with:
  * #10 
  * #60 
  * #99

.github/workflows/ci.yml

@@ -34,7 +34,7 @@ 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)

.gitignore

@@ -3,3 +3,4 @@
 .DS_Store
 .vscode
 lib/EpdFont/fontsrc
+*.generated.h

README.md

@@ -23,18 +23,23 @@ CrossPoint Reader aims to:
 
 This project is **not affiliated with Xteink**; it's built as a community project.
 
-## Features
+## Features & Usage
 
 - [x] EPUB parsing and rendering
+- [ ] Image support within EPUB
 - [x] Saved reading position
-- [ ] File explorer with file picker
+- [x] File explorer with file picker
   - [x] Basic EPUB picker from root directory
   - [x] Support nested folders
   - [ ] EPUB picker with cover art
-- [ ] Image support within EPUB
+- [x] Custom sleep screen
+  - [ ] Cover sleep screen
+- [x] Wifi book upload
+- [ ] Wifi OTA updates
 - [ ] Configurable font, layout, and display options
-- [ ] WiFi connectivity
-- [ ] BLE connectivity
+- [ ] Screen rotation
+
+See [the user guide](./USER_GUIDE.md) for instructions on operating CrossPoint.
 
 ## Installing
 
@@ -59,10 +64,6 @@ back to the other partition using the "Swap boot partition" button here https://
 
 See [Development](#development) below.
 
-## Usage
-
-See [the user guide](./USER_GUIDE.md) for instructions on operating CrossPoint.
-
 ## Development
 
 ### Prerequisites

USER_GUIDE.md

@@ -19,24 +19,72 @@ The device utilises the standard buttons on the Xtink X4 in the same layout:
 
 ### Power On / Off
 
-To turn the device on or off, **press and hold the Power button for 1 full second**.
+To turn the device on or off, **press and hold the Power button for half a second**. In **Settings** you can configure
+the power button to trigger on a short press instead of a long one.
 
 ### First Launch
 
-Upon turning the device on for the first time, you will be placed on the **Book Selection Screen** (File Browser).
+Upon turning the device on for the first time, you will be placed on the **Home** screen.
 
 > **Note:** On subsequent restarts, the firmware will automatically reopen the last book you were reading.
 
 ---
 
-## 3. Book Selection
+## 3. Screens
 
-The Home Screen acts as a folder and file browser.
+### 3.1 Home Screen
+
+The Home Screen is the main entry point to the firmware. From here you can navigate to the **Book Selection** screen,
+**Settings** screen, or **File Upload** screen.
+
+### 3.2 Book Selection (Read)
+
+The Book Selection acts as a folder and file browser.
 
 * **Navigate List:** Use **Left** (or **Volume Up**), or **Right** (or **Volume Down**) to move the selection cursor up 
   and down through folders and books.
 * **Open Selection:** Press **Confirm** to open a folder or read a selected book.
 
+### 3.3 Reading Screen
+
+See [4. Reading Mode](#4-reading-mode) below for more information.
+
+### 3.4 File Upload Screen
+
+The File Upload screen allows you to upload new e-books to the device. When you enter the screen you'll be prompted with
+a WiFi selection dialog and then your X4 will start hosting a web server.
+
+See the [webserver docs](./docs/webserver.md) for more information on how to connect to the web server and upload files.
+
+### 3.5 Settings
+
+The Settings screen allows you to configure the device's behavior. There are a few settings you can adjust:
+- **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
@@ -76,3 +124,4 @@ are planned for future updates:
 
 * **Images:** Embedded images in e-books will not render.
 * **Text Formatting:** There are currently no settings to adjust font type, size, line spacing, or margins.
+* **Rotation**: Different rotation options are not supported.

docs/webserver.md

@@ -0,0 +1,272 @@
+# Web Server Guide
+
+This guide explains how to connect your CrossPoint Reader to WiFi and use the built-in web server to upload EPUB files from your computer or phone.
+
+## Overview
+
+CrossPoint Reader includes a built-in web server that allows you to:
+
+- Upload EPUB files wirelessly from any device on the same WiFi network
+- Browse and manage files on your device's SD card
+- Create folders to organize your ebooks
+- Delete files and folders
+
+## Prerequisites
+
+- Your CrossPoint Reader device
+- A WiFi network
+- A computer, phone, or tablet connected to the **same WiFi network**
+
+---
+
+## Step 1: Accessing the WiFi Screen
+
+1. From the main menu or file browser, navigate to the **Settings** screen
+2. Select the **WiFi** option
+3. The device will automatically start scanning for available networks
+
+---
+
+## Step 2: Connecting to WiFi
+
+### Viewing Available Networks
+
+Once the scan completes, you'll see a list of available WiFi networks with the following indicators:
+
+- **Signal strength bars** (`||||`, `|||`, `||`, `|`) - Shows connection quality
+- **`*` symbol** - Indicates the network is password-protected (encrypted)
+- **`+` symbol** - Indicates you have previously saved credentials for this network
+
+<img src="./images/wifi/wifi_networks.jpeg" height="500">
+
+### Selecting a Network
+
+1. Use the **Left/Right** (or **Volume Up/Down**) buttons to navigate through the network list
+2. Press **Confirm** to select the highlighted network
+
+### Entering Password (for encrypted networks)
+
+If the network requires a password:
+
+1. An on-screen keyboard will appear
+2. Use the navigation buttons to select characters
+3. Press **Confirm** to enter each character
+4. When complete, select the **Done** option on the keyboard
+
+<img src="./images/wifi/wifi_password.jpeg" height="500">
+
+**Note:** If you've previously connected to this network, the saved password will be used automatically.
+
+### Connection Process
+
+The device will display "Connecting..." while establishing the connection. This typically takes 5-10 seconds.
+
+### Saving Credentials
+
+If this is a new network, you'll be prompted to save the password:
+
+- Select **Yes** to save credentials for automatic connection next time (NOTE: These are stored in plaintext on the device's SD card. Do not use this for sensitive networks.)
+- Select **No** to connect without saving
+
+---
+
+## Step 3: Connection Success
+
+Once connected, the screen will display:
+
+- **Network name** (SSID)
+- **IP Address** (e.g., `192.168.1.102`)
+- **Web server URL** (e.g., `http://192.168.1.102/`)
+
+<img src="./images/wifi/wifi_connected.jpeg" height="500">
+
+**Important:** Make note of the IP address - you'll need this to access the web interface from your computer or phone.
+
+---
+
+## Step 4: Accessing the Web Interface
+
+### From a Computer
+
+1. Ensure your computer is connected to the **same WiFi network** as your CrossPoint Reader
+2. Open any web browser (Chrome is recommended)
+3. Type the IP address shown on your device into the browser's address bar
+   - Example: `http://192.168.1.102/`
+4. Press Enter
+
+### From a Phone or Tablet
+
+1. Ensure your phone/tablet is connected to the **same WiFi network** as your CrossPoint Reader
+2. Open your mobile browser (Safari, Chrome, etc.)
+3. Type the IP address into the address bar
+   - Example: `http://192.168.1.102/`
+4. Tap Go
+
+---
+
+## Step 5: Using the Web Interface
+
+### Home Page
+
+The home page displays:
+
+- Device status and version information
+- WiFi connection status
+- Current IP address
+- Available memory
+
+Navigation links:
+
+- **Home** - Returns to the status page
+- **File Manager** - Access file management features
+
+<img src="./images/wifi/webserver_homepage.png" width="600">
+
+### File Manager
+
+Click **File Manager** to access file management features.
+
+#### Browsing Files
+
+- The file manager displays all files and folders on your SD card
+- **Folders** are highlighted in yellow with a 📁 icon
+- **EPUB files** are highlighted in green with a 📗 icon
+- Click on a folder name to navigate into it
+- Use the breadcrumb navigation at the top to go back to parent folders
+
+<img src="./images/wifi/webserver_files.png" width="600">
+
+#### Uploading EPUB Files
+
+1. Click the **+ Add** button in the top-right corner
+2. Select **Upload eBook** from the dropdown menu
+3. Click **Choose File** and select an `.epub` file from your device
+4. Click **Upload**
+5. A progress bar will show the upload status
+6. The page will automatically refresh when the upload is complete
+
+**Note:** Only `.epub` files are accepted. Other file types will be rejected.
+
+<img src="./images/wifi/webserver_upload.png" width="600">
+
+#### Creating Folders
+
+1. Click the **+ Add** button in the top-right corner
+2. Select **New Folder** from the dropdown menu
+3. Enter a folder name (letters, numbers, underscores, and hyphens only)
+4. Click **Create Folder**
+
+This is useful for organizing your ebooks by genre, author, or series.
+
+#### Deleting Files and Folders
+
+1. Click the **🗑️** (trash) icon next to any file or folder
+2. Confirm the deletion in the popup dialog
+3. Click **Delete** to permanently remove the item
+
+**Warning:** Deletion is permanent and cannot be undone!
+
+**Note:** Folders must be empty before they can be deleted.
+
+---
+
+## Troubleshooting
+
+### Cannot See the Device on the Network
+
+**Problem:** Browser shows "Cannot connect" or "Site can't be reached"
+
+**Solutions:**
+
+1. Verify both devices are on the **same WiFi network**
+   - Check your computer/phone WiFi settings
+   - Confirm the CrossPoint Reader shows "Connected" status
+2. Double-check the IP address
+   - Make sure you typed it correctly
+   - Include `http://` at the beginning
+3. Try disabling VPN if you're using one
+4. Some networks have "client isolation" enabled - check with your network administrator
+
+### Connection Drops or Times Out
+
+**Problem:** WiFi connection is unstable
+
+**Solutions:**
+
+1. Move closer to the WiFi router
+2. Check signal strength on the device (should be at least `||` or better)
+3. Avoid interference from other devices
+4. Try a different WiFi network if available
+
+### Upload Fails
+
+**Problem:** File upload doesn't complete or shows an error
+
+**Solutions:**
+
+1. Ensure the file is a valid `.epub` file
+2. Check that the SD card has enough free space
+3. Try uploading a smaller file first to test
+4. Refresh the browser page and try again
+
+### Saved Password Not Working
+
+**Problem:** Device fails to connect with saved credentials
+
+**Solutions:**
+
+1. When connection fails, you'll be prompted to "Forget Network"
+2. Select **Yes** to remove the saved password
+3. Reconnect and enter the password again
+4. Choose to save the new password
+
+---
+
+## Security Notes
+
+- The web server runs on port 80 (standard HTTP)
+- **No authentication is required** - anyone on the same network can access the interface
+- The web server is only accessible while the WiFi screen shows "Connected"
+- The web server automatically stops when you exit the WiFi screen
+- For security, only use on trusted private networks
+
+---
+
+## Technical Details
+
+- **Supported WiFi:** 2.4GHz networks (802.11 b/g/n)
+- **Web Server Port:** 80 (HTTP)
+- **Maximum Upload Size:** Limited by available SD card space
+- **Supported File Format:** `.epub` only
+- **Browser Compatibility:** All modern browsers (Chrome, Firefox, Safari, Edge)
+
+---
+
+## Tips and Best Practices
+
+1. **Organize with folders** - Create folders before uploading to keep your library organized
+2. **Check signal strength** - Stronger signals (`|||` or `||||`) provide faster, more reliable uploads
+3. **Upload multiple files** - You can upload files one at a time; the page refreshes after each upload
+4. **Use descriptive names** - Name your folders clearly (e.g., "SciFi", "Mystery", "Non-Fiction")
+5. **Keep credentials saved** - Save your WiFi password for quick reconnection in the future
+6. **Exit when done** - Press **Back** to exit the WiFi screen and save battery
+
+---
+
+## Exiting WiFi Mode
+
+When you're finished uploading files:
+
+1. Press the **Back** button on your CrossPoint Reader
+2. The web server will automatically stop
+3. WiFi will disconnect to conserve battery
+4. You'll return to the previous screen
+
+Your uploaded files will be immediately available in the file browser!
+
+---
+
+## Related Documentation
+
+- [User Guide](../USER_GUIDE.md) - General device operation
+- [README](../README.md) - Project overview and features

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());
@@ -63,137 +70,154 @@ 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;
-  if (!opfParser.coverItemId.empty() && opfParser.items.count(opfParser.coverItemId) > 0) {
-    coverImageItem = opfParser.items.at(opfParser.coverItemId);
-  }
+  bookMetadata.title = opfParser.title;
+  // TODO: Parse author
+  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;
-  if (!getItemSize(tocNcxItem, &tocSize)) {
-    Serial.printf("[%lu] [EBP] Could not get size of toc ncx\n", millis());
+  Serial.printf("[%lu] [EBP] Parsing toc ncx file: %s\n", millis(), tocNcxItem.c_str());
+
+  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)) {
-    Serial.printf("[%lu] [EBP] Could not read toc ncx stream\n", millis());
-    ncxParser.teardown();
+  const auto ncxBuffer = static_cast<uint8_t*>(malloc(1024));
+  if (!ncxBuffer) {
+    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;
-  if (!findContentOpfFile(&contentOpfFilePath)) {
-    Serial.printf("[%lu] [EBP] Could not find content.opf in zip\n", millis());
+  // Initialize spine/TOC cache
+  bookMetadataCache.reset(new BookMetadataCache(cachePath));
+
+  // 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());
-
-  contentBasePath = contentOpfFilePath.substr(0, contentOpfFilePath.find_last_of('/') + 1);
-
-  if (!parseContentOpf(contentOpfFilePath)) {
+  // OPF Pass
+  BookMetadataCache::BookMetadata bookMetadata;
+  if (!bookMetadataCache->beginContentOpfPass()) {
+    Serial.printf("[%lu] [EBP] Could not begin writing content.opf pass\n", millis());
+    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;
   }
-
-  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();
+  if (!bookMetadataCache->endTocPass()) {
+    Serial.printf("[%lu] [EBP] Could not end writing toc pass\n", millis());
+    return false;
   }
-  Serial.printf("[%lu] [EBP] Book size: %lu\n", millis(), cumSpineItemSize);
+
+  // 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;
+  }
+
+  Serial.printf("[%lu] [EBP] Loaded ePub: %s\n", millis(), filepath.c_str());
+  return true;
 }
 
 bool Epub::clearCache() const {
@@ -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::getCoverImageItem() const { return coverImageItem; }
-
-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;
-    }
+const std::string& Epub::getTitle() const {
+  static std::string blank;
+  if (!bookMetadataCache || !bookMetadataCache->isLoaded()) {
+    return blank;
   }
 
-  if (!component.empty()) {
-    components.push_back(component);
-  }
-
-  std::string result;
-  for (const auto& c : components) {
-    if (!result.empty()) {
-      result += "/";
-    }
-    result += c;
-  }
-
-  return result;
+  return bookMetadataCache->coreMetadata.title;
 }
 
-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) {
@@ -284,77 +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) {
-  if (spineIndex < 0 || spineIndex >= spine.size()) {
+BookMetadataCache::SpineEntry Epub::getSpineItem(const int spineIndex) const {
+  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) {
-  if (tocTndex < 0 || tocTndex >= toc.size()) {
-    Serial.printf("[%lu] [EBP] getTocItem index:%d is out of range\n", millis(), tocTndex);
-    return toc.at(0);
+BookMetadataCache::TocEntry Epub::getTocItem(const int tocIndex) const {
+  if (!bookMetadataCache || !bookMetadataCache->isLoaded()) {
+    Serial.printf("[%lu] [EBP] getTocItem called but cache not loaded\n", millis());
+    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 {
-  // the toc entry should have an href that matches the spine item
-  // so we can find the spine index by looking for the href
-  for (int i = 0; i < spine.size(); i++) {
-    if (spine[i].second == toc[tocIndex].href) {
-      return i;
-    }
+  if (!bookMetadataCache || !bookMetadataCache->isLoaded()) {
+    Serial.printf("[%lu] [EBP] getSpineIndexForTocIndex called but cache not loaded\n", millis());
+    return 0;
   }
 
-  Serial.printf("[%lu] [EBP] Section not found\n", millis());
-  // not found - default to the start of the book
-  return 0;
-}
-
-int Epub::getTocIndexForSpineIndex(const int spineIndex) const {
-  // 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;
-    }
+  if (tocIndex < 0 || tocIndex >= bookMetadataCache->getTocCount()) {
+    Serial.printf("[%lu] [EBP] getSpineIndexForTocIndex: tocIndex %d out of range\n", millis(), tocIndex);
+    return 0;
   }
 
-  Serial.printf("[%lu] [EBP] TOC item not found\n", millis());
-  return -1;
+  const int spineIndex = bookMetadataCache->getTocEntry(tocIndex).spineIndex;
+  if (spineIndex < 0) {
+    Serial.printf("[%lu] [EBP] Section not found for TOC index %d\n", millis(), tocIndex);
+    return 0;
+  }
+
+  return spineIndex;
 }
 
-size_t Epub::getBookSize() const { return getCumulativeSpineItemSize(getSpineItemsCount() - 1); }
+int Epub::getTocIndexForSpineIndex(const int spineIndex) const { return getSpineItem(spineIndex).tocIndex; }
+
+size_t Epub::getBookSize() const {
+  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) {
-  size_t prevChapterSize = (currentSpineIndex >= 1) ? getCumulativeSpineItemSize(currentSpineIndex - 1) : 0;
-  size_t curChapterSize = getCumulativeSpineItemSize(currentSpineIndex) - prevChapterSize;
-  size_t bookSize = getBookSize();
-  size_t sectionProgSize = currentSpineRead * curChapterSize;
+uint8_t Epub::calculateProgress(const int currentSpineIndex, const float currentSpineRead) const {
+  const size_t bookSize = getBookSize();
+  if (bookSize == 0) {
+    return 0;
+  }
+  const size_t prevChapterSize = (currentSpineIndex >= 1) ? getCumulativeSpineItemSize(currentSpineIndex - 1) : 0;
+  const size_t curChapterSize = getCumulativeSpineItemSize(currentSpineIndex) - prevChapterSize;
+  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 parseTocNcxFile();
-  void initializeSpineItemSizes();
+  bool parseContentOpf(BookMetadataCache::BookMetadata& bookMetadata);
+  bool parseTocNcxFile() const;
+  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) {
-  serialization::writePod(os, xPos);
-  serialization::writePod(os, yPos);
+void PageLine::serialize(File& file) {
+  serialization::writePod(file, xPos);
+  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(is, yPos);
+  serialization::readPod(file, xPos);
+  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 {
-  serialization::writePod(os, PAGE_FILE_VERSION);
+void Page::serialize(File& file) const {
+  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));
-    el->serialize(os);
+    serialization::writePod(file, static_cast<uint8_t>(TAG_PageLine));
+    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;
-  static std::unique_ptr<PageLine> deserialize(std::istream& is);
+  void serialize(File& file) override;
+  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;
-  static std::unique_ptr<Page> deserialize(std::istream& is);
+  void serialize(File& file) const;
+  static std::unique_ptr<Page> deserialize(File& file);
 };

lib/Epub/Epub/ParsedText.cpp

@@ -19,20 +19,35 @@ 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);
-  // width of 1em to indent first line of paragraph if Extra Spacing is enabled
-  const int indentWidth = (!extraParagraphSpacing) ? 1 * renderer.getTextWidth(fontId, "m", REGULAR) : 0;
+  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);
 
+  // add em-space at the beginning of first word in paragraph to indent
+  if (!extraParagraphSpacing) {
+    std::string& first_word = words.front();
+    first_word.insert(0, "\xe2\x80\x83");
+  }
+
   auto wordsIt = words.begin();
   auto wordStylesIt = wordStyles.begin();
 
@@ -43,6 +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'
@@ -53,7 +75,7 @@ void ParsedText::layoutAndExtractLines(const GfxRenderer& renderer, const int fo
   ans[totalWordCount - 1] = totalWordCount - 1;
 
   for (int i = totalWordCount - 2; i >= 0; --i) {
-    int currlen = -spaceWidth + indentWidth;
+    int currlen = -spaceWidth;
     dp[i] = MAX_COST;
 
     for (size_t j = i; j < totalWordCount; ++j) {
@@ -102,70 +124,59 @@ void ParsedText::layoutAndExtractLines(const GfxRenderer& renderer, const int fo
     currentWordIndex = nextBreakIndex;
   }
 
-  // Initialize iterators for consumption
-  auto wordStartIt = words.begin();
-  auto wordStyleStartIt = wordStyles.begin();
-  size_t wordWidthIndex = 0;
-
-  size_t lastBreakAt = 0;
-  for (const size_t lineBreak : lineBreakIndices) {
-    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) {
-      lineWordWidthSum += wordWidths[wordWidthIndex + i];
-    }
-
-    // Calculate spacing
-    int spareSpace = pageWidth - lineWordWidthSum;
-    if (wordWidthIndex == 0) {
-      spareSpace -= indentWidth;
-    }
-
-    int spacing = spaceWidth;
-    const bool isLastLine = lineBreak == totalWordCount;
-
-    if (style == TextBlock::JUSTIFIED && !isLastLine && lineWordCount >= 2) {
-      spacing = spareSpace / (lineWordCount - 1);
-    }
-
-    // Calculate initial x position
-    uint16_t xpos = (wordWidthIndex == 0) ? indentWidth : 0;
-
-    if (style == TextBlock::RIGHT_ALIGN) {
-      xpos = spareSpace - (lineWordCount - 1) * spaceWidth;
-    } else if (style == TextBlock::CENTER_ALIGN) {
-      xpos = (spareSpace - (lineWordCount - 1) * spaceWidth) / 2;
-    }
-
-    // Pre-calculate X positions for words
-    std::list<uint16_t> lineXPos;
-    for (size_t i = 0; i < lineWordCount; ++i) {
-      const uint16_t currentWordWidth = wordWidths[wordWidthIndex + i];
-      lineXPos.push_back(xpos);
-      xpos += currentWordWidth + spacing;
-    }
-
-    // *** CRITICAL STEP: CONSUME DATA USING SPLICE ***
-    std::list<std::string> lineWords;
-    lineWords.splice(lineWords.begin(), words, wordStartIt, wordEndIt);
-    std::list<EpdFontStyle> lineWordStyles;
-    lineWordStyles.splice(lineWordStyles.begin(), wordStyles, wordStyleStartIt, wordStyleEndIt);
-
-    processLine(
-        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;
-  }
+  return lineBreakIndices;
+}
+
+void ParsedText::extractLine(const size_t breakIndex, const int pageWidth, const int spaceWidth,
+                             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 total word width for this line
+  int lineWordWidthSum = 0;
+  for (size_t i = lastBreakAt; i < lineBreak; i++) {
+    lineWordWidthSum += wordWidths[i];
+  }
+
+  // Calculate spacing
+  const int spareSpace = pageWidth - lineWordWidthSum;
+
+  int spacing = spaceWidth;
+  const bool isLastLine = breakIndex == lineBreakIndices.size() - 1;
+
+  if (style == TextBlock::JUSTIFIED && !isLastLine && lineWordCount >= 2) {
+    spacing = spareSpace / (lineWordCount - 1);
+  }
+
+  // Calculate initial x position
+  uint16_t xpos = 0;
+  if (style == TextBlock::RIGHT_ALIGN) {
+    xpos = spareSpace - (lineWordCount - 1) * spaceWidth;
+  } else if (style == TextBlock::CENTER_ALIGN) {
+    xpos = (spareSpace - (lineWordCount - 1) * spaceWidth) / 2;
+  }
+
+  // Pre-calculate X positions for words
+  std::list<uint16_t> lineXPos;
+  for (size_t i = lastBreakAt; i < lineBreak; 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, words.begin(), wordEndIt);
+  std::list<EpdFontStyle> lineWordStyles;
+  lineWordStyles.splice(lineWordStyles.begin(), wordStyles, wordStyles.begin(), wordStyleEndIt);
+
+  processLine(std::make_shared<TextBlock>(std::move(lineWords), std::move(lineXPos), std::move(lineWordStyles), style));
 }

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 = 5;
 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();
 
@@ -28,7 +29,10 @@ void Section::onPageComplete(std::unique_ptr<Page> page) {
 void Section::writeCacheMetadata(const int fontId, const float lineCompression, const int marginTop,
                                  const int marginRight, const int marginBottom, const int marginLeft,
                                  const bool extraParagraphSpacing) 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);
@@ -44,17 +48,12 @@ 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) {
-  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;
@@ -117,15 +116,14 @@ 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 auto localPath = epub->getSpineItem(spineIndex);
-
-  // TODO: Should we get rid of this file all together?
-  //       It currently saves us a bit of memory by allowing for all the inflation bits to be released
-  //       before loading the XML parser
+  const auto localPath = epub->getSpineItem(spineIndex).href;
   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);
-  f.close();
+  File tmpHtml;
+  if (!FsHelpers::openFileForWrite("SCT", tmpHtmlPath, tmpHtml)) {
+    return false;
+  }
+  bool success = epub->readItemContentsToStream(localPath, tmpHtml, 1024);
+  tmpHtml.close();
 
   if (!success) {
     Serial.printf("[%lu] [SCT] Failed to stream item contents to temp file\n", millis());
@@ -134,10 +132,8 @@ bool Section::persistPageDataToSD(const int fontId, const float lineCompression,
 
   Serial.printf("[%lu] [SCT] Streamed temp HTML to %s\n", millis(), tmpHtmlPath.c_str());
 
-  const auto sdTmpHtmlPath = "/sd" + tmpHtmlPath;
-
-  ChapterHtmlSlimParser visitor(sdTmpHtmlPath.c_str(), renderer, fontId, lineCompression, marginTop, marginRight,
-                                marginBottom, marginLeft, extraParagraphSpacing,
+  ChapterHtmlSlimParser visitor(tmpHtmlPath, renderer, fontId, lineCompression, marginTop, marginRight, marginBottom,
+                                marginLeft, extraParagraphSpacing,
                                 [this](std::unique_ptr<Page> page) { this->onPageComplete(std::move(page)); });
   success = visitor.parseAndBuildPages();
 
@@ -153,13 +149,12 @@ 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";
-  if (!SD.exists(filePath.c_str() + 3)) {
-    Serial.printf("[%lu] [SCT] Page file does not exist: %s\n", millis(), filePath.c_str());
+  const auto filePath = cachePath + "/page_" + std::to_string(currentPage) + ".bin";
+
+  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

@@ -21,9 +21,10 @@ class Section {
   int currentPage = 0;
 
   explicit Section(const std::shared_ptr<Epub>& epub, const int spineIndex, GfxRenderer& renderer)
-      : epub(epub), spineIndex(spineIndex), renderer(renderer) {
-    cachePath = epub->getCachePath() + "/" + std::to_string(spineIndex);
-  }
+      : epub(epub),
+        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);

lib/Epub/Epub/blocks/TextBlock.cpp

@@ -17,27 +17,27 @@ 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);
-  for (const auto& w : words) serialization::writeString(os, w);
+  serialization::writePod(file, wc);
+  for (const auto& w : words) serialization::writeString(file, w);
 
   // wordXpos
   const uint32_t xc = wordXpos.size();
-  serialization::writePod(os, xc);
-  for (auto x : wordXpos) serialization::writePod(os, x);
+  serialization::writePod(file, xc);
+  for (auto x : wordXpos) serialization::writePod(file, x);
 
   // wordStyles
   const uint32_t sc = wordStyles.size();
-  serialization::writePod(os, sc);
-  for (auto s : wordStyles) serialization::writePod(os, s);
+  serialization::writePod(file, sc);
+  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 +45,22 @@ std::unique_ptr<TextBlock> TextBlock::deserialize(std::istream& is) {
   BLOCK_STYLE style;
 
   // words
-  serialization::readPod(is, wc);
+  serialization::readPod(file, wc);
   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);
 
   // 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;
-  static std::unique_ptr<TextBlock> deserialize(std::istream& is);
+  void serialize(File& file) const;
+  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 +11,13 @@
 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"};
+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"};
@@ -75,6 +76,18 @@ void XMLCALL ChapterHtmlSlimParser::startElement(void* userData, const XML_Char*
     return;
   }
 
+  // Skip blocks with role="doc-pagebreak" and epub:type="pagebreak"
+  if (atts != nullptr) {
+    for (int i = 0; atts[i]; i += 2) {
+      if (strcmp(atts[i], "role") == 0 && strcmp(atts[i + 1], "doc-pagebreak") == 0 ||
+          strcmp(atts[i], "epub:type") == 0 && strcmp(atts[i + 1], "pagebreak") == 0) {
+        self->skipUntilDepth = self->depth;
+        self->depth += 1;
+        return;
+      }
+    }
+  }
+
   if (matches(name, HEADER_TAGS, NUM_HEADER_TAGS)) {
     self->startNewTextBlock(TextBlock::CENTER_ALIGN);
     self->boldUntilDepth = min(self->boldUntilDepth, self->depth);
@@ -131,6 +144,17 @@ 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) {
@@ -191,48 +215,59 @@ bool ChapterHtmlSlimParser::parseAndBuildPages() {
     return false;
   }
 
-  XML_SetUserData(parser, this);
-  XML_SetElementHandler(parser, startElement, endElement);
-  XML_SetCharacterDataHandler(parser, characterData);
-
-  FILE* file = fopen(filepath, "r");
-  if (!file) {
-    Serial.printf("[%lu] [EHP] Couldn't open file %s\n", millis(), filepath);
+  File file;
+  if (!FsHelpers::openFileForRead("EHP", filepath, file)) {
     XML_ParserFree(parser);
     return false;
   }
 
+  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);
+    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

@@ -15,7 +15,7 @@ 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;
   int depth = 0;
@@ -45,7 +45,7 @@ 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)

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()) {
@@ -140,14 +175,29 @@ void XMLCALL ContentOpfParser::startElement(void* userData, const XML_Char* name
     return;
   }
 
-  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]);
-        break;
+  // 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) {
+          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;
     }
-    return;
   }
 }
 
@@ -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::map<std::string, std::string> items;
-  std::vector<std::string> spineRefs;
+  std::string coverItemHref;
 
-  explicit ContentOpfParser(const std::string& baseContentPath, const size_t xmlSize)
-      : baseContentPath(baseContentPath), remainingSize(xmlSize) {}
+  explicit ContentOpfParser(const std::string& cachePath, const std::string& baseContentPath, const size_t 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
-      self->toc.emplace_back(self->currentLabel, href, anchor, self->currentDepth);
+      if (self->cache) {
+        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"
-#include "expat.h"
+class BookMetadataCache;
 
 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)
-      : baseContentPath(baseContentPath), remainingSize(xmlSize) {}
+  explicit TocNcxParser(const std::string& baseContentPath, const size_t xmlSize, BookMetadataCache* cache)
+      : baseContentPath(baseContentPath), remainingSize(xmlSize), cache(cache) {}
+  ~TocNcxParser() override;
 
   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

@@ -0,0 +1,200 @@
+#include "Bitmap.h"
+
+#include <cstdlib>
+#include <cstring>
+
+uint16_t Bitmap::readLE16(File& f) {
+  const int c0 = f.read();
+  const int c1 = f.read();
+  const auto b0 = static_cast<uint8_t>(c0 < 0 ? 0 : c0);
+  const auto b1 = static_cast<uint8_t>(c1 < 0 ? 0 : c1);
+  return static_cast<uint16_t>(b0) | (static_cast<uint16_t>(b1) << 8);
+}
+
+uint32_t Bitmap::readLE32(File& f) {
+  const int c0 = f.read();
+  const int c1 = f.read();
+  const int c2 = f.read();
+  const int c3 = f.read();
+
+  const auto b0 = static_cast<uint8_t>(c0 < 0 ? 0 : c0);
+  const auto b1 = static_cast<uint8_t>(c1 < 0 ? 0 : c1);
+  const auto b2 = static_cast<uint8_t>(c2 < 0 ? 0 : c2);
+  const auto b3 = static_cast<uint8_t>(c3 < 0 ? 0 : c3);
+
+  return static_cast<uint32_t>(b0) | (static_cast<uint32_t>(b1) << 8) | (static_cast<uint32_t>(b2) << 16) |
+         (static_cast<uint32_t>(b3) << 24);
+}
+
+const char* Bitmap::errorToString(BmpReaderError err) {
+  switch (err) {
+    case BmpReaderError::Ok:
+      return "Ok";
+    case BmpReaderError::FileInvalid:
+      return "FileInvalid";
+    case BmpReaderError::SeekStartFailed:
+      return "SeekStartFailed";
+    case BmpReaderError::NotBMP:
+      return "NotBMP (missing 'BM')";
+    case BmpReaderError::DIBTooSmall:
+      return "DIBTooSmall (<40 bytes)";
+    case BmpReaderError::BadPlanes:
+      return "BadPlanes (!= 1)";
+    case BmpReaderError::UnsupportedBpp:
+      return "UnsupportedBpp (expected 1, 2, 8, 24, or 32)";
+    case BmpReaderError::UnsupportedCompression:
+      return "UnsupportedCompression (expected BI_RGB or BI_BITFIELDS for 32bpp)";
+    case BmpReaderError::BadDimensions:
+      return "BadDimensions";
+    case BmpReaderError::PaletteTooLarge:
+      return "PaletteTooLarge";
+
+    case BmpReaderError::SeekPixelDataFailed:
+      return "SeekPixelDataFailed";
+    case BmpReaderError::BufferTooSmall:
+      return "BufferTooSmall";
+
+    case BmpReaderError::OomRowBuffer:
+      return "OomRowBuffer";
+    case BmpReaderError::ShortReadRow:
+      return "ShortReadRow";
+  }
+  return "Unknown";
+}
+
+BmpReaderError Bitmap::parseHeaders() {
+  if (!file) return BmpReaderError::FileInvalid;
+  if (!file.seek(0)) return BmpReaderError::SeekStartFailed;
+
+  // --- BMP FILE HEADER ---
+  const uint16_t bfType = readLE16(file);
+  if (bfType != 0x4D42) return BmpReaderError::NotBMP;
+
+  file.seek(8, SeekCur);
+  bfOffBits = readLE32(file);
+
+  // --- DIB HEADER ---
+  const uint32_t biSize = readLE32(file);
+  if (biSize < 40) return BmpReaderError::DIBTooSmall;
+
+  width = static_cast<int32_t>(readLE32(file));
+  const auto rawHeight = static_cast<int32_t>(readLE32(file));
+  topDown = rawHeight < 0;
+  height = topDown ? -rawHeight : rawHeight;
+
+  const uint16_t planes = readLE16(file);
+  bpp = readLE16(file);
+  const uint32_t comp = readLE32(file);
+  const bool validBpp = bpp == 1 || bpp == 2 || bpp == 8 || bpp == 24 || bpp == 32;
+
+  if (planes != 1) return BmpReaderError::BadPlanes;
+  if (!validBpp) return BmpReaderError::UnsupportedBpp;
+  // Allow BI_RGB (0) for all, and BI_BITFIELDS (3) for 32bpp which is common for BGRA masks.
+  if (!(comp == 0 || (bpp == 32 && comp == 3))) return BmpReaderError::UnsupportedCompression;
+
+  file.seek(12, SeekCur);  // biSizeImage, biXPelsPerMeter, biYPelsPerMeter
+  const uint32_t colorsUsed = readLE32(file);
+  if (colorsUsed > 256u) return BmpReaderError::PaletteTooLarge;
+  file.seek(4, SeekCur);  // biClrImportant
+
+  if (width <= 0 || height <= 0) return BmpReaderError::BadDimensions;
+
+  // Pre-calculate Row Bytes to avoid doing this every row
+  rowBytes = (width * bpp + 31) / 32 * 4;
+
+  for (int i = 0; i < 256; i++) paletteLum[i] = static_cast<uint8_t>(i);
+  if (colorsUsed > 0) {
+    for (uint32_t i = 0; i < colorsUsed; i++) {
+      uint8_t rgb[4];
+      file.read(rgb, 4);  // Read B, G, R, Reserved in one go
+      paletteLum[i] = (77u * rgb[2] + 150u * rgb[1] + 29u * rgb[0]) >> 8;
+    }
+  }
+
+  if (!file.seek(bfOffBits)) {
+    return BmpReaderError::SeekPixelDataFailed;
+  }
+
+  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 {
+  // Note: rowBuffer should be pre-allocated by the caller to size 'rowBytes'
+  if (file.read(rowBuffer, rowBytes) != rowBytes) return BmpReaderError::ShortReadRow;
+
+  uint8_t* outPtr = data;
+  uint8_t currentOutByte = 0;
+  int bitShift = 6;
+
+  // Helper lambda to pack 2bpp color into the output stream
+  auto packPixel = [&](const uint8_t lum) {
+    uint8_t color = (lum >> 6);  // Simple 2-bit reduction: 0-255 -> 0-3
+    currentOutByte |= (color << bitShift);
+    if (bitShift == 0) {
+      *outPtr++ = currentOutByte;
+      currentOutByte = 0;
+      bitShift = 6;
+    } else {
+      bitShift -= 2;
+    }
+  };
+
+  uint8_t lum;
+
+  switch (bpp) {
+    case 32: {
+      const uint8_t* p = rowBuffer;
+      for (int x = 0; x < width; 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++) {
+        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++) {
+        lum = (rowBuffer[x >> 3] & (0x80 >> (x & 7))) ? 0xFF : 0x00;
+        packPixel(lum);
+      }
+      break;
+    }
+    default:
+      return BmpReaderError::UnsupportedBpp;
+  }
+
+  // Flush remaining bits if width is not a multiple of 4
+  if (bitShift != 6) *outPtr = currentOutByte;
+
+  return BmpReaderError::Ok;
+}
+
+BmpReaderError Bitmap::rewindToData() const {
+  if (!file.seek(bfOffBits)) {
+    return BmpReaderError::SeekPixelDataFailed;
+  }
+
+  return BmpReaderError::Ok;
+}

lib/GfxRenderer/Bitmap.h

@@ -0,0 +1,52 @@
+#pragma once
+
+#include <FS.h>
+
+enum class BmpReaderError : uint8_t {
+  Ok = 0,
+  FileInvalid,
+  SeekStartFailed,
+
+  NotBMP,
+  DIBTooSmall,
+
+  BadPlanes,
+  UnsupportedBpp,
+  UnsupportedCompression,
+
+  BadDimensions,
+  PaletteTooLarge,
+
+  SeekPixelDataFailed,
+  BufferTooSmall,
+  OomRowBuffer,
+  ShortReadRow,
+};
+
+class Bitmap {
+ public:
+  static const char* errorToString(BmpReaderError err);
+
+  explicit Bitmap(File& file) : file(file) {}
+  BmpReaderError parseHeaders();
+  BmpReaderError readRow(uint8_t* data, uint8_t* rowBuffer) const;
+  BmpReaderError rewindToData() const;
+  int getWidth() const { return width; }
+  int getHeight() const { return height; }
+  bool isTopDown() const { return topDown; }
+  bool hasGreyscale() const { return bpp > 1; }
+  int getRowBytes() const { return rowBytes; }
+
+ private:
+  static uint16_t readLE16(File& f);
+  static uint32_t readLE32(File& f);
+
+  File& file;
+  int width = 0;
+  int height = 0;
+  bool topDown = false;
+  uint32_t bfOffBits = 0;
+  uint16_t bpp = 0;
+  int rowBytes = 0;
+  uint8_t paletteLum[256] = {};
+};

lib/GfxRenderer/GfxRenderer.cpp

@@ -119,10 +119,81 @@ void GfxRenderer::drawImage(const uint8_t bitmap[], const int x, const int y, co
   einkDisplay.drawImage(bitmap, y, x, height, width);
 }
 
+void GfxRenderer::drawBitmap(const Bitmap& bitmap, const int x, const int y, const int maxWidth,
+                             const int maxHeight) const {
+  float scale = 1.0f;
+  bool isScaled = false;
+  if (maxWidth > 0 && bitmap.getWidth() > maxWidth) {
+    scale = static_cast<float>(maxWidth) / static_cast<float>(bitmap.getWidth());
+    isScaled = true;
+  }
+  if (maxHeight > 0 && bitmap.getHeight() > maxHeight) {
+    scale = std::min(scale, static_cast<float>(maxHeight) / static_cast<float>(bitmap.getHeight()));
+    isScaled = true;
+  }
+
+  const uint8_t 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.
+    int screenY = y + (bitmap.isTopDown() ? bmpY : bitmap.getHeight() - 1 - bmpY);
+    if (isScaled) {
+      screenY = std::floor(screenY * scale);
+    }
+    if (screenY >= getScreenHeight()) {
+      break;
+    }
+
+    if (bitmap.readRow(outputRow, rowBytes) != BmpReaderError::Ok) {
+      Serial.printf("[%lu] [GFX] Failed to read row %d from bitmap\n", millis(), bmpY);
+      free(outputRow);
+      free(rowBytes);
+      return;
+    }
+
+    for (int bmpX = 0; bmpX < bitmap.getWidth(); bmpX++) {
+      int screenX = x + bmpX;
+      if (isScaled) {
+        screenX = std::floor(screenX * scale);
+      }
+      if (screenX >= getScreenWidth()) {
+        break;
+      }
+
+      const uint8_t val = outputRow[bmpX / 4] >> (6 - ((bmpX * 2) % 8)) & 0x3;
+
+      if (renderMode == BW && val < 3) {
+        drawPixel(screenX, screenY);
+      } else if (renderMode == GRAYSCALE_MSB && (val == 1 || val == 2)) {
+        drawPixel(screenX, screenY, false);
+      } else if (renderMode == GRAYSCALE_LSB && val == 1) {
+        drawPixel(screenX, screenY, false);
+      }
+    }
+  }
+
+  free(outputRow);
+  free(rowBytes);
+}
+
 void GfxRenderer::clearScreen(const uint8_t color) const { einkDisplay.clearScreen(color); }
 
 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];
   }
@@ -196,6 +267,10 @@ 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++) {
@@ -246,6 +321,12 @@ 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

@@ -2,9 +2,12 @@
 
 #include <EInkDisplay.h>
 #include <EpdFontFamily.h>
+#include <FS.h>
 
 #include <map>
 
+#include "Bitmap.h"
+
 class GfxRenderer {
  public:
   enum RenderMode { BW, GRAYSCALE_LSB, GRAYSCALE_MSB };
@@ -45,6 +48,7 @@ class GfxRenderer {
   void drawRect(int x, int y, int width, int height, bool state = true) const;
   void fillRect(int x, int y, int width, int height, bool state = true) const;
   void drawImage(const uint8_t bitmap[], int x, int y, int width, int height) const;
+  void drawBitmap(const Bitmap& bitmap, int x, int y, int maxWidth, int maxHeight) const;
 
   // Text
   int getTextWidth(int fontId, const char* text, EpdFontStyle style = REGULAR) const;

lib/JpegToBmpConverter/JpegToBmpConverter.cpp

@@ -0,0 +1,258 @@
+#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;
+};
+
+// Helper function: Convert 8-bit grayscale to 2-bit (0-3)
+uint8_t JpegToBmpConverter::grayscaleTo2Bit(const uint8_t grayscale) {
+  // Simple threshold mapping:
+  // 0-63 -> 0 (black)
+  // 64-127 -> 1 (dark gray)
+  // 128-191 -> 2 (light gray)
+  // 192-255 -> 3 (white)
+  return grayscale >> 6;
+}
+
+inline void write16(Print& out, const uint16_t value) {
+  // out.write(reinterpret_cast<const uint8_t *>(&value), 2);
+  out.write(value & 0xFF);
+  out.write((value >> 8) & 0xFF);
+}
+
+inline void write32(Print& out, const uint32_t value) {
+  // out.write(reinterpret_cast<const uint8_t *>(&value), 4);
+  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(reinterpret_cast<const uint8_t *>(&value), 4);
+  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 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);
+
+  // Write BMP header
+  writeBmpHeader(bmpOut, imageInfo.m_width, imageInfo.m_height);
+
+  // Calculate row parameters
+  const int bytesPerRow = (imageInfo.m_width * 2 + 31) / 32 * 4;
+
+  // Allocate row buffer for packed 2-bit pixels
+  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;
+  auto* mcuRowBuffer = static_cast<uint8_t*>(malloc(mcuRowPixels));
+  if (!mcuRowBuffer) {
+    Serial.printf("[%lu] [JPG] Failed to allocate MCU row buffer\n", millis());
+    free(rowBuffer);
+    return false;
+  }
+
+  // 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;
+      }
+
+      // Process MCU block into MCU row buffer
+      // MCUs are composed of 8x8 blocks. For 16x16 MCUs, there are four 8x8 blocks:
+      // Block layout for 16x16 MCU:  [0, 64]  (top row of blocks)
+      //                              [128, 192] (bottom row of blocks)
+      for (int blockY = 0; blockY < mcuPixelHeight; blockY++) {
+        for (int blockX = 0; blockX < mcuPixelWidth; blockX++) {
+          const int pixelX = mcuX * mcuPixelWidth + blockX;
+
+          // Skip pixels outside image width (can happen with MCU alignment)
+          if (pixelX >= imageInfo.m_width) {
+            continue;
+          }
+
+          // Calculate which 8x8 block and position within that block
+          const int block8x8Col = blockX / 8;  // 0 or 1 for 16-wide MCU
+          const int block8x8Row = blockY / 8;  // 0 or 1 for 16-tall MCU
+          const int pixelInBlockX = blockX % 8;
+          const int pixelInBlockY = blockY % 8;
+
+          // Calculate byte offset: each 8x8 block is 64 bytes
+          // Blocks are arranged: [0, 64], [128, 192]
+          const int blockOffset = (block8x8Row * (mcuPixelWidth / 8) + block8x8Col) * 64;
+          const int mcuIndex = blockOffset + pixelInBlockY * 8 + pixelInBlockX;
+
+          // Get grayscale value
+          uint8_t gray;
+          if (imageInfo.m_comps == 1) {
+            // Grayscale image
+            gray = imageInfo.m_pMCUBufR[mcuIndex];
+          } else {
+            // RGB image - convert to grayscale
+            const uint8_t r = imageInfo.m_pMCUBufR[mcuIndex];
+            const uint8_t g = imageInfo.m_pMCUBufG[mcuIndex];
+            const uint8_t b = imageInfo.m_pMCUBufB[mcuIndex];
+            // Luminance formula: Y = 0.299*R + 0.587*G + 0.114*B
+            // Using integer approximation: (30*R + 59*G + 11*B) / 100
+            gray = (r * 30 + g * 59 + b * 11) / 100;
+          }
+
+          // Store grayscale value in MCU row buffer
+          mcuRowBuffer[blockY * imageInfo.m_width + pixelX] = gray;
+        }
+      }
+    }
+
+    // Write all pixel rows from this MCU row to BMP file
+    const int startRow = mcuY * mcuPixelHeight;
+    const int endRow = (mcuY + 1) * mcuPixelHeight;
+
+    for (int y = startRow; y < endRow && y < imageInfo.m_height; y++) {
+      memset(rowBuffer, 0, bytesPerRow);
+
+      // Pack 4 pixels per byte (2 bits each)
+      for (int x = 0; x < imageInfo.m_width; x++) {
+        const int bufferY = y - startRow;
+        const uint8_t gray = mcuRowBuffer[bufferY * imageInfo.m_width + x];
+        const uint8_t twoBit = grayscaleTo2Bit(gray);
+
+        const int byteIndex = (x * 2) / 8;
+        const int bitOffset = 6 - ((x * 2) % 8);  // 6, 4, 2, 0
+        rowBuffer[byteIndex] |= (twoBit << bitOffset);
+      }
+
+      // Write row with padding
+      bmpOut.write(rowBuffer, bytesPerRow);
+    }
+  }
+
+  // Clean up
+  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);
+  static uint8_t grayscaleTo2Bit(uint8_t grayscale);
+  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 {
-  mz_zip_archive zipArchive = {};
-  const bool status = mz_zip_reader_init_file(&zipArchive, filePath.c_str(), 0);
+ZipFile::ZipFile(std::string filePath) : filePath(std::move(filePath)) {
+  const bool status = mz_zip_reader_init_file(&zipArchive, this->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;
 }
 
@@ -62,6 +59,10 @@ long ZipFile::getDataOffset(const mz_zip_archive_file_stat& fileStat) const {
   const uint64_t fileOffset = fileStat.m_local_header_ofs;
 
   FILE* file = fopen(filePath.c_str(), "r");
+  if (!file) {
+    Serial.printf("[%lu] [ZIP] Failed to open file for reading local header\n", millis());
+    return -1;
+  }
   fseek(file, fileOffset, SEEK_SET);
   const size_t read = fread(pLocalHeader, 1, localHeaderSize, file);
   fclose(file);
@@ -104,12 +105,21 @@ uint8_t* ZipFile::readFileToMemory(const char* filename, size_t* size, const boo
   }
 
   FILE* file = fopen(filePath.c_str(), "rb");
+  if (!file) {
+    Serial.printf("[%lu] [ZIP] Failed to open file for reading\n", millis());
+    return nullptr;
+  }
   fseek(file, fileOffset, SEEK_SET);
 
   const auto deflatedDataSize = static_cast<size_t>(fileStat.m_comp_size);
   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
@@ -175,6 +185,10 @@ bool ZipFile::readFileToStream(const char* filename, Print& out, const size_t ch
   }
 
   FILE* file = fopen(filePath.c_str(), "rb");
+  if (!file) {
+    Serial.printf("[%lu] [ZIP] Failed to open file for streaming\n", millis());
+    return false;
+  }
   fseek(file, fileOffset, SEEK_SET);
 
   const auto deflatedDataSize = static_cast<size_t>(fileStat.m_comp_size);

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)) {}
-  ~ZipFile() = default;
+  explicit ZipFile(std::string filePath);
+  ~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
@@ -31,11 +31,15 @@ board_build.flash_mode = dio
 board_build.flash_size = 16MB
 board_build.partitions = partitions.csv
 
+extra_scripts =
+  pre:scripts/build_html.py
+
 ; Libraries
 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
 
 [env:default]
 extends = base

scripts/build_html.py

@@ -0,0 +1,51 @@
+import os
+import re
+
+SRC_DIR = "src"
+
+def minify_html(html: str) -> str:
+    # Tags where whitespace should be preserved
+    preserve_tags = ['pre', 'code', 'textarea', 'script', 'style']
+    preserve_regex = '|'.join(preserve_tags)
+
+    # Protect preserve blocks with placeholders
+    preserve_blocks = []
+    def preserve(match):
+        preserve_blocks.append(match.group(0))
+        return f"__PRESERVE_BLOCK_{len(preserve_blocks)-1}__"
+
+    html = re.sub(rf'<({preserve_regex})[\s\S]*?</\1>', preserve, html, flags=re.IGNORECASE)
+
+    # Remove HTML comments
+    html = re.sub(r'<!--.*?-->', '', html, flags=re.DOTALL)
+
+    # Collapse all whitespace between tags
+    html = re.sub(r'>\s+<', '><', html)
+
+    # Collapse multiple spaces inside tags
+    html = re.sub(r'\s+', ' ', html)
+
+    # Restore preserved blocks
+    for i, block in enumerate(preserve_blocks):
+        html = html.replace(f"__PRESERVE_BLOCK_{i}__", block)
+
+    return html.strip()
+
+for root, _, files in os.walk(SRC_DIR):
+    for file in files:
+        if file.endswith(".html"):
+            html_path = os.path.join(root, file)
+            with open(html_path, "r", encoding="utf-8") as f:
+                html_content = f.read()
+
+            # minified = regex.sub("\g<1>", html_content)
+            minified = minify_html(html_content)
+            base_name = f"{os.path.splitext(file)[0]}Html"
+            header_path = os.path.join(root, f"{base_name}.generated.h")
+
+            with open(header_path, "w", encoding="utf-8") as h:
+                h.write(f"// THIS FILE IS AUTOGENERATED, DO NOT EDIT MANUALLY\n\n")
+                h.write(f"#pragma once\n")
+                h.write(f'constexpr char {base_name}[] PROGMEM = R"rawliteral({minified})rawliteral";\n')
+
+            print(f"Generated: {header_path}")

src/CrossPointSettings.cpp

@@ -1,30 +1,33 @@
 #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;
-constexpr uint8_t SETTINGS_COUNT = 2;
-constexpr char SETTINGS_FILE[] = "/sd/.crosspoint/settings.bin";
+constexpr uint8_t SETTINGS_COUNT = 3;
+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);
   outputFile.close();
 
   Serial.printf("[%lu] [CPS] Settings saved to file\n", millis());
@@ -32,13 +35,11 @@ bool CrossPointSettings::saveToFile() const {
 }
 
 bool CrossPointSettings::loadFromFile() {
-  if (!SD.exists(SETTINGS_FILE + 3)) {  // +3 to skip "/sd" prefix
-    Serial.printf("[%lu] [CPS] Settings file does not exist, using defaults\n", millis());
+  File inputFile;
+  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) {
@@ -51,15 +52,15 @@ bool CrossPointSettings::loadFromFile() {
   serialization::readPod(inputFile, fileSettingsCount);
 
   // load settings that exist
-  switch (fileSettingsCount) {
-    case 1:
-      serialization::readPod(inputFile, whiteSleepScreen);
-      break;
-    case 2:
-      serialization::readPod(inputFile, whiteSleepScreen);
-      serialization::readPod(inputFile, extraParagraphSpacing);
-      break;
-  }
+  uint8_t settingsRead = 0;
+  do {
+    serialization::readPod(inputFile, sleepScreen);
+    if (++settingsRead >= fileSettingsCount) break;
+    serialization::readPod(inputFile, extraParagraphSpacing);
+    if (++settingsRead >= fileSettingsCount) break;
+    serialization::readPod(inputFile, shortPwrBtn);
+    if (++settingsRead >= fileSettingsCount) break;
+  } while (false);
 
   inputFile.close();
   Serial.printf("[%lu] [CPS] Settings loaded from file\n", millis());

src/CrossPointSettings.h

@@ -15,17 +15,23 @@ class CrossPointSettings {
   CrossPointSettings(const CrossPointSettings&) = delete;
   CrossPointSettings& operator=(const CrossPointSettings&) = delete;
 
-  // Sleep screen settings
-  uint8_t whiteSleepScreen = 0;
+  // Should match with SettingsActivity text
+  enum SLEEP_SCREEN_MODE { DARK = 0, LIGHT = 1, CUSTOM = 2, COVER = 3 };
 
+  // Sleep screen settings
+  uint8_t sleepScreen = DARK;
   // Text rendering settings
   uint8_t extraParagraphSpacing = 1;
+  // Duration of the power button press
+  uint8_t shortPwrBtn = 0;
 
   ~CrossPointSettings() = default;
 
   // Get singleton instance
   static CrossPointSettings& getInstance() { return instance; }
 
+  uint16_t getPowerButtonDuration() const { return shortPwrBtn ? 10 : 500; }
+
   bool saveToFile() const;
   bool loadFromFile();
 };

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

@@ -0,0 +1,154 @@
+#include "WifiCredentialStore.h"
+
+#include <FsHelpers.h>
+#include <HardwareSerial.h>
+#include <SD.h>
+#include <Serialization.h>
+
+// Initialize the static instance
+WifiCredentialStore WifiCredentialStore::instance;
+
+namespace {
+// File format version
+constexpr uint8_t WIFI_FILE_VERSION = 1;
+
+// WiFi credentials file path
+constexpr char WIFI_FILE[] = "/.crosspoint/wifi.bin";
+
+// Obfuscation key - "CrossPoint" in ASCII
+// This is NOT cryptographic security, just prevents casual file reading
+constexpr uint8_t OBFUSCATION_KEY[] = {0x43, 0x72, 0x6F, 0x73, 0x73, 0x50, 0x6F, 0x69, 0x6E, 0x74};
+constexpr size_t KEY_LENGTH = sizeof(OBFUSCATION_KEY);
+}  // namespace
+
+void WifiCredentialStore::obfuscate(std::string& data) const {
+  Serial.printf("[%lu] [WCS] Obfuscating/deobfuscating %zu bytes\n", millis(), data.size());
+  for (size_t i = 0; i < data.size(); i++) {
+    data[i] ^= OBFUSCATION_KEY[i % KEY_LENGTH];
+  }
+}
+
+bool WifiCredentialStore::saveToFile() const {
+  // Make sure the directory exists
+  SD.mkdir("/.crosspoint");
+
+  File file;
+  if (!FsHelpers::openFileForWrite("WCS", WIFI_FILE, file)) {
+    return false;
+  }
+
+  // Write header
+  serialization::writePod(file, WIFI_FILE_VERSION);
+  serialization::writePod(file, static_cast<uint8_t>(credentials.size()));
+
+  // Write each credential
+  for (const auto& cred : credentials) {
+    // Write SSID (plaintext - not sensitive)
+    serialization::writeString(file, cred.ssid);
+    Serial.printf("[%lu] [WCS] Saving SSID: %s, password length: %zu\n", millis(), cred.ssid.c_str(),
+                  cred.password.size());
+
+    // Write password (obfuscated)
+    std::string obfuscatedPwd = cred.password;
+    obfuscate(obfuscatedPwd);
+    serialization::writeString(file, obfuscatedPwd);
+  }
+
+  file.close();
+  Serial.printf("[%lu] [WCS] Saved %zu WiFi credentials to file\n", millis(), credentials.size());
+  return true;
+}
+
+bool WifiCredentialStore::loadFromFile() {
+  File file;
+  if (!FsHelpers::openFileForRead("WCS", WIFI_FILE, file)) {
+    return false;
+  }
+
+  // Read and verify version
+  uint8_t version;
+  serialization::readPod(file, version);
+  if (version != WIFI_FILE_VERSION) {
+    Serial.printf("[%lu] [WCS] Unknown file version: %u\n", millis(), version);
+    file.close();
+    return false;
+  }
+
+  // Read credential count
+  uint8_t count;
+  serialization::readPod(file, count);
+
+  // Read credentials
+  credentials.clear();
+  for (uint8_t i = 0; i < count && i < MAX_NETWORKS; i++) {
+    WifiCredential cred;
+
+    // Read SSID
+    serialization::readString(file, cred.ssid);
+
+    // Read and deobfuscate password
+    serialization::readString(file, cred.password);
+    Serial.printf("[%lu] [WCS] Loaded SSID: %s, obfuscated password length: %zu\n", millis(), cred.ssid.c_str(),
+                  cred.password.size());
+    obfuscate(cred.password);  // XOR is symmetric, so same function deobfuscates
+    Serial.printf("[%lu] [WCS] After deobfuscation, password length: %zu\n", millis(), cred.password.size());
+
+    credentials.push_back(cred);
+  }
+
+  file.close();
+  Serial.printf("[%lu] [WCS] Loaded %zu WiFi credentials from file\n", millis(), credentials.size());
+  return true;
+}
+
+bool WifiCredentialStore::addCredential(const std::string& ssid, const std::string& password) {
+  // Check if this SSID already exists and update it
+  const auto cred = find_if(credentials.begin(), credentials.end(),
+                            [&ssid](const WifiCredential& cred) { return cred.ssid == ssid; });
+  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) {
+    Serial.printf("[%lu] [WCS] Cannot add more networks, limit of %zu reached\n", millis(), MAX_NETWORKS);
+    return false;
+  }
+
+  // Add new credential
+  credentials.push_back({ssid, password});
+  Serial.printf("[%lu] [WCS] Added credentials for: %s\n", millis(), ssid.c_str());
+  return saveToFile();
+}
+
+bool WifiCredentialStore::removeCredential(const std::string& ssid) {
+  const auto cred = find_if(credentials.begin(), credentials.end(),
+                            [&ssid](const WifiCredential& cred) { return cred.ssid == ssid; });
+  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 {
+  const auto cred = find_if(credentials.begin(), credentials.end(),
+                            [&ssid](const WifiCredential& cred) { return cred.ssid == ssid; });
+
+  if (cred != credentials.end()) {
+    return &*cred;
+  }
+
+  return nullptr;
+}
+
+bool WifiCredentialStore::hasSavedCredential(const std::string& ssid) const { return findCredential(ssid) != nullptr; }
+
+void WifiCredentialStore::clearAll() {
+  credentials.clear();
+  saveToFile();
+  Serial.printf("[%lu] [WCS] Cleared all WiFi credentials\n", millis());
+}

src/WifiCredentialStore.h

@@ -0,0 +1,56 @@
+#pragma once
+#include <string>
+#include <vector>
+
+struct WifiCredential {
+  std::string ssid;
+  std::string password;  // Stored obfuscated in file
+};
+
+/**
+ * Singleton class for storing WiFi credentials on the SD card.
+ * Credentials are stored in /sd/.crosspoint/wifi.bin with basic
+ * XOR obfuscation to prevent casual reading (not cryptographically secure).
+ */
+class WifiCredentialStore {
+ private:
+  static WifiCredentialStore instance;
+  std::vector<WifiCredential> credentials;
+
+  static constexpr size_t MAX_NETWORKS = 8;
+
+  // Private constructor for singleton
+  WifiCredentialStore() = default;
+
+  // XOR obfuscation (symmetric - same for encode/decode)
+  void obfuscate(std::string& data) const;
+
+ public:
+  // Delete copy constructor and assignment
+  WifiCredentialStore(const WifiCredentialStore&) = delete;
+  WifiCredentialStore& operator=(const WifiCredentialStore&) = delete;
+
+  // Get singleton instance
+  static WifiCredentialStore& getInstance() { return instance; }
+
+  // Save/load from SD card
+  bool saveToFile() const;
+  bool loadFromFile();
+
+  // Credential management
+  bool addCredential(const std::string& ssid, const std::string& password);
+  bool removeCredential(const std::string& ssid);
+  const WifiCredential* findCredential(const std::string& ssid) const;
+
+  // Get all stored credentials (for UI display)
+  const std::vector<WifiCredential>& getCredentials() const { return credentials; }
+
+  // Check if a network is saved
+  bool hasSavedCredential(const std::string& ssid) const;
+
+  // Clear all credentials
+  void clearAll();
+};
+
+// Helper macro to access credentials store
+#define WIFI_STORE WifiCredentialStore::getInstance()

src/activities/Activity.h

@@ -1,18 +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)
-      : renderer(renderer), inputManager(inputManager) {}
+  explicit Activity(std::string name, GfxRenderer& renderer, InputManager& inputManager)
+      : name(std::move(name)), renderer(renderer), inputManager(inputManager) {}
   virtual ~Activity() = default;
-  virtual void onEnter() {}
-  virtual void onExit() {}
+  virtual void onEnter() { Serial.printf("[%lu] [ACT] Entering activity: %s\n", millis(), name.c_str()); }
+  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)
-      : Activity(renderer, inputManager) {}
+  explicit ActivityWithSubactivity(std::string name, GfxRenderer& renderer, InputManager& 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

@@ -1,24 +1,200 @@
 #include "SleepActivity.h"
 
+#include <Epub.h>
+#include <FsHelpers.h>
 #include <GfxRenderer.h>
+#include <SD.h>
+
+#include <vector>
 
 #include "CrossPointSettings.h"
+#include "CrossPointState.h"
 #include "config.h"
 #include "images/CrossLarge.h"
 
 void SleepActivity::onEnter() {
-  const auto pageWidth = GfxRenderer::getScreenWidth();
-  const auto pageHeight = GfxRenderer::getScreenHeight();
+  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()) {
+    std::vector<std::string> files;
+    // collect all valid BMP files
+    for (File file = dir.openNextFile(); file; file = dir.openNextFile()) {
+      if (file.isDirectory()) {
+        file.close();
+        continue;
+      }
+      auto filename = std::string(file.name());
+      if (filename[0] == '.') {
+        file.close();
+        continue;
+      }
+
+      if (filename.substr(filename.length() - 4) != ".bmp") {
+        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());
+        file.close();
+        continue;
+      }
+      files.emplace_back(filename);
+      file.close();
+    }
+    const auto numFiles = files.size();
+    if (numFiles > 0) {
+      // Generate a random number between 1 and numFiles
+      const auto randomFileIndex = random(numFiles);
+      const auto filename = "/sleep/" + files[randomFileIndex];
+      File file;
+      if (FsHelpers::openFileForRead("SLP", filename, file)) {
+        Serial.printf("[%lu] [SLP] Randomly loading: /sleep/%s\n", millis(), files[randomFileIndex].c_str());
+        delay(100);
+        Bitmap bitmap(file);
+        if (bitmap.parseHeaders() == BmpReaderError::Ok) {
+          renderBitmapSleepScreen(bitmap);
+          dir.close();
+          return;
+        }
+      }
+    }
+  }
+  if (dir) dir.close();
+
+  // 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.
+  File 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());
+      renderBitmapSleepScreen(bitmap);
+      return;
+    }
+  }
+
+  renderDefaultSleepScreen();
+}
+
+void SleepActivity::renderDefaultSleepScreen() const {
+  const auto pageWidth = renderer.getScreenWidth();
+  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
-  if (!SETTINGS.whiteSleepScreen) {
+  // Make sleep screen dark unless light is selected in settings
+  if (SETTINGS.sleepScreen != CrossPointSettings::SLEEP_SCREEN_MODE::LIGHT) {
     renderer.invertScreen();
   }
 
   renderer.displayBuffer(EInkDisplay::HALF_REFRESH);
 }
+
+void SleepActivity::renderBitmapSleepScreen(const Bitmap& bitmap) const {
+  int x, y;
+  const auto pageWidth = renderer.getScreenWidth();
+  const auto pageHeight = renderer.getScreenHeight();
+
+  if (bitmap.getWidth() > pageWidth || bitmap.getHeight() > pageHeight) {
+    // image will scale, make sure placement is right
+    const float ratio = static_cast<float>(bitmap.getWidth()) / static_cast<float>(bitmap.getHeight());
+    const float screenRatio = static_cast<float>(pageWidth) / static_cast<float>(pageHeight);
+
+    if (ratio > screenRatio) {
+      // image wider than viewport ratio, scaled down image needs to be centered vertically
+      x = 0;
+      y = (pageHeight - pageWidth / ratio) / 2;
+    } else {
+      // image taller than viewport ratio, scaled down image needs to be centered horizontally
+      x = (pageWidth - pageHeight * ratio) / 2;
+      y = 0;
+    }
+  } else {
+    // center the image
+    x = (pageWidth - bitmap.getWidth()) / 2;
+    y = (pageHeight - bitmap.getHeight()) / 2;
+  }
+
+  renderer.clearScreen();
+  renderer.drawBitmap(bitmap, x, y, pageWidth, pageHeight);
+  renderer.displayBuffer(EInkDisplay::HALF_REFRESH);
+
+  if (bitmap.hasGreyscale()) {
+    bitmap.rewindToData();
+    renderer.clearScreen(0x00);
+    renderer.setRenderMode(GfxRenderer::GRAYSCALE_LSB);
+    renderer.drawBitmap(bitmap, x, y, pageWidth, pageHeight);
+    renderer.copyGrayscaleLsbBuffers();
+
+    bitmap.rewindToData();
+    renderer.clearScreen(0x00);
+    renderer.setRenderMode(GfxRenderer::GRAYSCALE_MSB);
+    renderer.drawBitmap(bitmap, x, y, pageWidth, pageHeight);
+    renderer.copyGrayscaleMsbBuffers();
+
+    renderer.displayGrayBuffer();
+    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

@@ -1,8 +1,18 @@
 #pragma once
 #include "../Activity.h"
 
+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 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

@@ -1,12 +1,13 @@
 #include "HomeActivity.h"
 
 #include <GfxRenderer.h>
+#include <InputManager.h>
 #include <SD.h>
 
 #include "config.h"
 
 namespace {
-constexpr int menuItemCount = 2;
+constexpr int menuItemCount = 3;
 }
 
 void HomeActivity::taskTrampoline(void* param) {
@@ -15,6 +16,8 @@ void HomeActivity::taskTrampoline(void* param) {
 }
 
 void HomeActivity::onEnter() {
+  Activity::onEnter();
+
   renderingMutex = xSemaphoreCreateMutex();
 
   selectorIndex = 0;
@@ -31,6 +34,8 @@ 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) {
@@ -51,6 +56,8 @@ void HomeActivity::loop() {
     if (selectorIndex == 0) {
       onReaderOpen();
     } else if (selectorIndex == 1) {
+      onFileTransferOpen();
+    } else if (selectorIndex == 2) {
       onSettingsOpen();
     }
   } else if (prevPressed) {
@@ -77,14 +84,15 @@ void HomeActivity::displayTaskLoop() {
 void HomeActivity::render() const {
   renderer.clearScreen();
 
-  const auto pageWidth = GfxRenderer::getScreenWidth();
-  const auto pageHeight = GfxRenderer::getScreenHeight();
+  const auto pageWidth = renderer.getScreenWidth();
+  const auto pageHeight = renderer.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, "Settings", selectorIndex != 1);
+  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);
   renderer.drawText(UI_FONT_ID, 25 + (105 - renderer.getTextWidth(UI_FONT_ID, "Back")) / 2, pageHeight - 35, "Back");

src/activities/home/HomeActivity.h

@@ -14,6 +14,7 @@ class HomeActivity final : public Activity {
   bool updateRequired = false;
   const std::function<void()> onReaderOpen;
   const std::function<void()> onSettingsOpen;
+  const std::function<void()> onFileTransferOpen;
 
   static void taskTrampoline(void* param);
   [[noreturn]] void displayTaskLoop();
@@ -21,8 +22,11 @@ class HomeActivity final : public Activity {
 
  public:
   explicit HomeActivity(GfxRenderer& renderer, InputManager& inputManager, const std::function<void()>& onReaderOpen,
-                        const std::function<void()>& onSettingsOpen)
-      : Activity(renderer, inputManager), onReaderOpen(onReaderOpen), onSettingsOpen(onSettingsOpen) {}
+                        const std::function<void()>& onSettingsOpen, const std::function<void()>& onFileTransferOpen)
+      : Activity("Home", renderer, inputManager),
+        onReaderOpen(onReaderOpen),
+        onSettingsOpen(onSettingsOpen),
+        onFileTransferOpen(onFileTransferOpen) {}
   void onEnter() override;
   void onExit() override;
   void loop() override;

src/activities/network/CrossPointWebServerActivity.cpp

@@ -0,0 +1,393 @@
+#include "CrossPointWebServerActivity.h"
+
+#include <DNSServer.h>
+#include <ESPmDNS.h>
+#include <GfxRenderer.h>
+#include <InputManager.h>
+#include <WiFi.h>
+
+#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() {
+  ActivityWithSubactivity::onEnter();
+
+  Serial.printf("[%lu] [WEBACT] [MEM] Free heap at onEnter: %d bytes\n", millis(), ESP.getFreeHeap());
+
+  renderingMutex = xSemaphoreCreateMutex();
+
+  // Reset state
+  state = WebServerActivityState::MODE_SELECTION;
+  networkMode = NetworkMode::JOIN_NETWORK;
+  isApMode = false;
+  connectedIP.clear();
+  connectedSSID.clear();
+  lastHandleClientTime = 0;
+  updateRequired = true;
+
+  xTaskCreate(&CrossPointWebServerActivity::taskTrampoline, "WebServerActivityTask",
+              2048,               // Stack size
+              this,               // Parameters
+              1,                  // Priority
+              &displayTaskHandle  // Task handle
+  );
+
+  // Launch network mode selection subactivity
+  Serial.printf("[%lu] [WEBACT] Launching NetworkModeSelectionActivity...\n", millis());
+  enterNewActivity(new NetworkModeSelectionActivity(
+      renderer, inputManager, [this](const NetworkMode mode) { onNetworkModeSelected(mode); },
+      [this]() { onGoBack(); }  // Cancel goes back to home
+      ));
+}
+
+void CrossPointWebServerActivity::onExit() {
+  ActivityWithSubactivity::onExit();
+
+  Serial.printf("[%lu] [WEBACT] [MEM] Free heap at onExit start: %d bytes\n", millis(), ESP.getFreeHeap());
+
+  state = WebServerActivityState::SHUTTING_DOWN;
+
+  // Stop the web server first (before disconnecting WiFi)
+  stopWebServer();
+
+  // Stop mDNS
+  MDNS.end();
+
+  // Stop DNS server if running (AP mode)
+  if (dnsServer) {
+    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
+  Serial.printf("[%lu] [WEBACT] Waiting 500ms for network stack to flush pending packets...\n", millis());
+  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());
+  WiFi.mode(WIFI_OFF);
+  delay(100);  // Allow WiFi hardware to fully power down
+
+  Serial.printf("[%lu] [WEBACT] [MEM] Free heap after WiFi disconnect: %d bytes\n", millis(), ESP.getFreeHeap());
+
+  // Acquire mutex before deleting task
+  Serial.printf("[%lu] [WEBACT] Acquiring rendering mutex before task deletion...\n", millis());
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
+
+  // Delete the display task
+  Serial.printf("[%lu] [WEBACT] Deleting display task...\n", millis());
+  if (displayTaskHandle) {
+    vTaskDelete(displayTaskHandle);
+    displayTaskHandle = nullptr;
+    Serial.printf("[%lu] [WEBACT] Display task deleted\n", millis());
+  }
+
+  // Delete the mutex
+  Serial.printf("[%lu] [WEBACT] Deleting mutex...\n", millis());
+  vSemaphoreDelete(renderingMutex);
+  renderingMutex = nullptr;
+  Serial.printf("[%lu] [WEBACT] Mutex deleted\n", millis());
+
+  Serial.printf("[%lu] [WEBACT] [MEM] Free heap at onExit end: %d bytes\n", millis(), ESP.getFreeHeap());
+}
+
+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 = static_cast<WifiSelectionActivity*>(subActivity.get())->getConnectedIP();
+    connectedSSID = WiFi.SSID().c_str();
+    isApMode = false;
+
+    exitActivity();
+
+    // 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 to mode selection
+    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());
+
+  // Create the web server instance
+  webServer.reset(new CrossPointWebServer());
+  webServer->begin();
+
+  if (webServer->isRunning()) {
+    state = WebServerActivityState::SERVER_RUNNING;
+    Serial.printf("[%lu] [WEBACT] Web server started successfully\n", millis());
+
+    // Force an immediate render since we're transitioning from a subactivity
+    // that had its own rendering task. We need to make sure our display is shown.
+    xSemaphoreTake(renderingMutex, portMAX_DELAY);
+    render();
+    xSemaphoreGive(renderingMutex);
+    Serial.printf("[%lu] [WEBACT] Rendered File Transfer screen\n", millis());
+  } else {
+    Serial.printf("[%lu] [WEBACT] ERROR: Failed to start web server!\n", millis());
+    webServer.reset();
+    // Go back on error
+    onGoBack();
+  }
+}
+
+void CrossPointWebServerActivity::stopWebServer() {
+  if (webServer && webServer->isRunning()) {
+    Serial.printf("[%lu] [WEBACT] Stopping web server...\n", millis());
+    webServer->stop();
+    Serial.printf("[%lu] [WEBACT] Web server stopped\n", millis());
+  }
+  webServer.reset();
+}
+
+void CrossPointWebServerActivity::loop() {
+  if (subActivity) {
+    // Forward loop to subactivity
+    subActivity->loop();
+    return;
+  }
+
+  // Handle different states
+  if (state == WebServerActivityState::SERVER_RUNNING) {
+    // Handle DNS requests for captive portal (AP mode only)
+    if (isApMode && dnsServer) {
+      dnsServer->processNextRequest();
+    }
+
+    // Handle web server requests - call handleClient multiple times per loop
+    // to improve responsiveness and upload throughput
+    if (webServer && webServer->isRunning()) {
+      const unsigned long timeSinceLastHandleClient = millis() - lastHandleClientTime;
+
+      // Log if there's a significant gap between handleClient calls (>100ms)
+      if (lastHandleClientTime > 0 && timeSinceLastHandleClient > 100) {
+        Serial.printf("[%lu] [WEBACT] WARNING: %lu ms gap since last handleClient\n", millis(),
+                      timeSinceLastHandleClient);
+      }
+
+      // Call handleClient multiple times to process pending requests faster
+      // This is critical for upload performance - HTTP file uploads send data
+      // in chunks and each handleClient() call processes incoming data
+      constexpr int HANDLE_CLIENT_ITERATIONS = 10;
+      for (int i = 0; i < HANDLE_CLIENT_ITERATIONS && webServer->isRunning(); i++) {
+        webServer->handleClient();
+      }
+      lastHandleClientTime = millis();
+    }
+
+    // Handle exit on Back button
+    if (inputManager.wasPressed(InputManager::BTN_BACK)) {
+      onGoBack();
+      return;
+    }
+  }
+}
+
+void CrossPointWebServerActivity::displayTaskLoop() {
+  while (true) {
+    if (updateRequired) {
+      updateRequired = false;
+      xSemaphoreTake(renderingMutex, portMAX_DELAY);
+      render();
+      xSemaphoreGive(renderingMutex);
+    }
+    vTaskDelay(10 / portTICK_PERIOD_MS);
+  }
+}
+
+void CrossPointWebServerActivity::render() const {
+  // Only render our own UI when server is running
+  // 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 CrossPointWebServerActivity::renderServerRunning() const {
+  const auto pageHeight = renderer.getScreenHeight();
+
+  // Use consistent line spacing
+  constexpr int LINE_SPACING = 28;  // Space between lines
+
+  renderer.drawCenteredText(READER_FONT_ID, 15, "File Transfer", true, BOLD);
+
+  if (isApMode) {
+    // AP mode display - center the content block
+    const 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);
+
+    // 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);
+  } else {
+    // STA mode display (original behavior)
+    const int startY = 65;
+
+    std::string ssidInfo = "Network: " + connectedSSID;
+    if (ssidInfo.length() > 28) {
+      ssidInfo.replace(25, ssidInfo.length() - 25, "...");
+    }
+    renderer.drawCenteredText(UI_FONT_ID, startY, ssidInfo.c_str(), true, REGULAR);
+
+    std::string ipInfo = "IP Address: " + connectedIP;
+    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, startY + LINE_SPACING * 2, webInfo.c_str(), true, BOLD);
+
+    // 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, startY + LINE_SPACING * 4, "Open this URL in your browser", true, REGULAR);
+  }
+
+  renderer.drawCenteredText(SMALL_FONT_ID, pageHeight - 30, "Press BACK to exit", true, REGULAR);
+}

src/activities/network/CrossPointWebServerActivity.h

@@ -0,0 +1,73 @@
+#pragma once
+#include <freertos/FreeRTOS.h>
+#include <freertos/semphr.h>
+#include <freertos/task.h>
+
+#include <functional>
+#include <memory>
+#include <string>
+
+#include "NetworkModeSelectionActivity.h"
+#include "activities/ActivityWithSubactivity.h"
+#include "network/CrossPointWebServer.h"
+
+// Web server activity states
+enum class WebServerActivityState {
+  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
+};
+
+/**
+ * CrossPointWebServerActivity is the entry point for file transfer functionality.
+ * It:
+ * - First presents a choice between "Join a Network" (STA) and "Create Hotspot" (AP)
+ * - 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 ActivityWithSubactivity {
+  TaskHandle_t displayTaskHandle = nullptr;
+  SemaphoreHandle_t renderingMutex = nullptr;
+  bool updateRequired = false;
+  WebServerActivityState state = WebServerActivityState::MODE_SELECTION;
+  const std::function<void()> onGoBack;
+
+  // Network mode
+  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;  // For STA mode: network name, For AP mode: AP name
+
+  // Performance monitoring
+  unsigned long lastHandleClientTime = 0;
+
+  static void taskTrampoline(void* param);
+  [[noreturn]] void displayTaskLoop();
+  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)
+      : ActivityWithSubactivity("CrossPointWebServer", renderer, inputManager), onGoBack(onGoBack) {}
+  void onEnter() override;
+  void onExit() override;
+  void loop() override;
+  bool skipLoopDelay() override { return webServer && webServer->isRunning(); }
+};

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.drawCenteredText(SMALL_FONT_ID, pageHeight - 30, "Press OK to select, BACK to cancel", true, REGULAR);
+
+  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

@@ -0,0 +1,700 @@
+#include "WifiSelectionActivity.h"
+
+#include <GfxRenderer.h>
+#include <WiFi.h>
+
+#include <map>
+
+#include "WifiCredentialStore.h"
+#include "activities/util/KeyboardEntryActivity.h"
+#include "config.h"
+
+void WifiSelectionActivity::taskTrampoline(void* param) {
+  auto* self = static_cast<WifiSelectionActivity*>(param);
+  self->displayTaskLoop();
+}
+
+void WifiSelectionActivity::onEnter() {
+  Activity::onEnter();
+
+  renderingMutex = xSemaphoreCreateMutex();
+
+  // 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;
+  networks.clear();
+  state = WifiSelectionState::SCANNING;
+  selectedSSID.clear();
+  connectedIP.clear();
+  connectionError.clear();
+  enteredPassword.clear();
+  usedSavedPassword = false;
+  savePromptSelection = 0;
+  forgetPromptSelection = 0;
+
+  // Trigger first update to show scanning message
+  updateRequired = true;
+
+  xTaskCreate(&WifiSelectionActivity::taskTrampoline, "WifiSelectionTask",
+              4096,               // Stack size (larger for WiFi operations)
+              this,               // Parameters
+              1,                  // Priority
+              &displayTaskHandle  // Task handle
+  );
+
+  // Start WiFi scan
+  startWifiScan();
+}
+
+void WifiSelectionActivity::onExit() {
+  Activity::onExit();
+
+  Serial.printf("[%lu] [WIFI] [MEM] Free heap at onExit start: %d bytes\n", millis(), ESP.getFreeHeap());
+
+  // Stop any ongoing WiFi scan
+  Serial.printf("[%lu] [WIFI] Deleting WiFi scan...\n", millis());
+  WiFi.scanDelete();
+  Serial.printf("[%lu] [WIFI] [MEM] Free heap after scanDelete: %d bytes\n", millis(), ESP.getFreeHeap());
+
+  // Note: We do NOT disconnect WiFi here - the parent activity (CrossPointWebServerActivity)
+  // manages WiFi connection state. We just clean up the scan and task.
+
+  // Acquire mutex before deleting task to ensure task isn't using it
+  // This prevents hangs/crashes if the task holds the mutex when deleted
+  Serial.printf("[%lu] [WIFI] Acquiring rendering mutex before task deletion...\n", millis());
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
+
+  // Delete the display task (we now hold the mutex, so task is blocked if it needs it)
+  Serial.printf("[%lu] [WIFI] Deleting display task...\n", millis());
+  if (displayTaskHandle) {
+    vTaskDelete(displayTaskHandle);
+    displayTaskHandle = nullptr;
+    Serial.printf("[%lu] [WIFI] Display task deleted\n", millis());
+  }
+
+  // Now safe to delete the mutex since we own it
+  Serial.printf("[%lu] [WIFI] Deleting mutex...\n", millis());
+  vSemaphoreDelete(renderingMutex);
+  renderingMutex = nullptr;
+  Serial.printf("[%lu] [WIFI] Mutex deleted\n", millis());
+
+  Serial.printf("[%lu] [WIFI] [MEM] Free heap at onExit end: %d bytes\n", millis(), ESP.getFreeHeap());
+}
+
+void WifiSelectionActivity::startWifiScan() {
+  state = WifiSelectionState::SCANNING;
+  networks.clear();
+  updateRequired = true;
+
+  // Set WiFi mode to station
+  WiFi.mode(WIFI_STA);
+  WiFi.disconnect();
+  delay(100);
+
+  // Start async scan
+  WiFi.scanNetworks(true);  // true = async scan
+}
+
+void WifiSelectionActivity::processWifiScanResults() {
+  const int16_t scanResult = WiFi.scanComplete();
+
+  if (scanResult == WIFI_SCAN_RUNNING) {
+    // Scan still in progress
+    return;
+  }
+
+  if (scanResult == WIFI_SCAN_FAILED) {
+    state = WifiSelectionState::NETWORK_LIST;
+    updateRequired = true;
+    return;
+  }
+
+  // Scan complete, process results
+  // Use a map to deduplicate networks by SSID, keeping the strongest signal
+  std::map<std::string, WifiNetworkInfo> uniqueNetworks;
+
+  for (int i = 0; i < scanResult; i++) {
+    std::string ssid = WiFi.SSID(i).c_str();
+    const int32_t rssi = WiFi.RSSI(i);
+
+    // Skip hidden networks (empty SSID)
+    if (ssid.empty()) {
+      continue;
+    }
+
+    // Check if we've already seen this SSID
+    auto it = uniqueNetworks.find(ssid);
+    if (it == uniqueNetworks.end() || rssi > it->second.rssi) {
+      // New network or stronger signal than existing entry
+      WifiNetworkInfo network;
+      network.ssid = ssid;
+      network.rssi = rssi;
+      network.isEncrypted = (WiFi.encryptionType(i) != WIFI_AUTH_OPEN);
+      network.hasSavedPassword = WIFI_STORE.hasSavedCredential(network.ssid);
+      uniqueNetworks[ssid] = network;
+    }
+  }
+
+  // Convert map to vector
+  networks.clear();
+  for (const auto& pair : uniqueNetworks) {
+    // cppcheck-suppress useStlAlgorithm
+    networks.push_back(pair.second);
+  }
+
+  // Sort by signal strength (strongest first)
+  std::sort(networks.begin(), networks.end(),
+            [](const WifiNetworkInfo& a, const WifiNetworkInfo& b) { return a.rssi > b.rssi; });
+
+  WiFi.scanDelete();
+  state = WifiSelectionState::NETWORK_LIST;
+  selectedNetworkIndex = 0;
+  updateRequired = true;
+}
+
+void WifiSelectionActivity::selectNetwork(const int index) {
+  if (index < 0 || index >= static_cast<int>(networks.size())) {
+    return;
+  }
+
+  const auto& network = networks[index];
+  selectedSSID = network.ssid;
+  selectedRequiresPassword = network.isEncrypted;
+  usedSavedPassword = false;
+  enteredPassword.clear();
+
+  // Check if we have saved credentials for this network
+  const auto* savedCred = WIFI_STORE.findCredential(selectedSSID);
+  if (savedCred && !savedCred->password.empty()) {
+    // Use saved password - connect directly
+    enteredPassword = savedCred->password;
+    usedSavedPassword = true;
+    Serial.printf("[%lu] [WiFi] Using saved password for %s, length: %zu\n", millis(), selectedSSID.c_str(),
+                  enteredPassword.size());
+    attemptConnection();
+    return;
+  }
+
+  if (selectedRequiresPassword) {
+    // Show password entry
+    state = WifiSelectionState::PASSWORD_ENTRY;
+    enterNewActivity(new KeyboardEntryActivity(renderer, inputManager, "Enter WiFi Password",
+                                               "",    // No initial text
+                                               64,    // Max password length
+                                               false  // Show password by default (hard keyboard to use)
+                                               ));
+    updateRequired = true;
+  } else {
+    // Connect directly for open networks
+    attemptConnection();
+  }
+}
+
+void WifiSelectionActivity::attemptConnection() {
+  state = WifiSelectionState::CONNECTING;
+  connectionStartTime = millis();
+  connectedIP.clear();
+  connectionError.clear();
+  updateRequired = true;
+
+  WiFi.mode(WIFI_STA);
+
+  // Get password from keyboard if we just entered it
+  if (subActivity && !usedSavedPassword) {
+    enteredPassword = static_cast<KeyboardEntryActivity*>(subActivity.get())->getText();
+  }
+
+  if (selectedRequiresPassword && !enteredPassword.empty()) {
+    WiFi.begin(selectedSSID.c_str(), enteredPassword.c_str());
+  } else {
+    WiFi.begin(selectedSSID.c_str());
+  }
+}
+
+void WifiSelectionActivity::checkConnectionStatus() {
+  if (state != WifiSelectionState::CONNECTING) {
+    return;
+  }
+
+  const wl_status_t status = WiFi.status();
+
+  if (status == WL_CONNECTED) {
+    // Successfully connected
+    IPAddress ip = WiFi.localIP();
+    char ipStr[16];
+    snprintf(ipStr, sizeof(ipStr), "%d.%d.%d.%d", ip[0], ip[1], ip[2], ip[3]);
+    connectedIP = ipStr;
+
+    // If we entered a new password, ask if user wants to save it
+    // Otherwise, immediately complete so parent can start web server
+    if (!usedSavedPassword && !enteredPassword.empty()) {
+      state = WifiSelectionState::SAVE_PROMPT;
+      savePromptSelection = 0;  // Default to "Yes"
+      updateRequired = true;
+    } else {
+      // Using saved password or open network - complete immediately
+      Serial.printf("[%lu] [WIFI] Connected with saved/open credentials, completing immediately\n", millis());
+      onComplete(true);
+    }
+    return;
+  }
+
+  if (status == WL_CONNECT_FAILED || status == WL_NO_SSID_AVAIL) {
+    connectionError = "Connection failed";
+    if (status == WL_NO_SSID_AVAIL) {
+      connectionError = "Network not found";
+    }
+    state = WifiSelectionState::CONNECTION_FAILED;
+    updateRequired = true;
+    return;
+  }
+
+  // Check for timeout
+  if (millis() - connectionStartTime > CONNECTION_TIMEOUT_MS) {
+    WiFi.disconnect();
+    connectionError = "Connection timeout";
+    state = WifiSelectionState::CONNECTION_FAILED;
+    updateRequired = true;
+    return;
+  }
+}
+
+void WifiSelectionActivity::loop() {
+  // Check scan progress
+  if (state == WifiSelectionState::SCANNING) {
+    processWifiScanResults();
+    return;
+  }
+
+  // Check connection progress
+  if (state == WifiSelectionState::CONNECTING) {
+    checkConnectionStatus();
+    return;
+  }
+
+  // Handle password entry state
+  if (state == WifiSelectionState::PASSWORD_ENTRY && subActivity) {
+    const auto keyboard = static_cast<KeyboardEntryActivity*>(subActivity.get());
+    keyboard->handleInput();
+
+    if (keyboard->isComplete()) {
+      attemptConnection();
+      return;
+    }
+
+    if (keyboard->isCancelled()) {
+      state = WifiSelectionState::NETWORK_LIST;
+      exitActivity();
+      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)) {
+      if (savePromptSelection > 0) {
+        savePromptSelection--;
+        updateRequired = true;
+      }
+    } else if (inputManager.wasPressed(InputManager::BTN_RIGHT) || inputManager.wasPressed(InputManager::BTN_DOWN)) {
+      if (savePromptSelection < 1) {
+        savePromptSelection++;
+        updateRequired = true;
+      }
+    } 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);
+    } else if (inputManager.wasPressed(InputManager::BTN_BACK)) {
+      // Skip saving, complete anyway
+      onComplete(true);
+    }
+    return;
+  }
+
+  // Handle forget prompt state (connection failed with saved credentials)
+  if (state == WifiSelectionState::FORGET_PROMPT) {
+    if (inputManager.wasPressed(InputManager::BTN_LEFT) || inputManager.wasPressed(InputManager::BTN_UP)) {
+      if (forgetPromptSelection > 0) {
+        forgetPromptSelection--;
+        updateRequired = true;
+      }
+    } else if (inputManager.wasPressed(InputManager::BTN_RIGHT) || inputManager.wasPressed(InputManager::BTN_DOWN)) {
+      if (forgetPromptSelection < 1) {
+        forgetPromptSelection++;
+        updateRequired = true;
+      }
+    } 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
+        const auto network = find_if(networks.begin(), networks.end(),
+                                     [this](const WifiNetworkInfo& net) { return net.ssid == selectedSSID; });
+        if (network != networks.end()) {
+          network->hasSavedPassword = false;
+        }
+      }
+      // Go back to network list
+      state = WifiSelectionState::NETWORK_LIST;
+      updateRequired = true;
+    } else if (inputManager.wasPressed(InputManager::BTN_BACK)) {
+      // Skip forgetting, go back to network list
+      state = WifiSelectionState::NETWORK_LIST;
+      updateRequired = true;
+    }
+    return;
+  }
+
+  // Handle connected state (should not normally be reached - connection completes immediately)
+  if (state == WifiSelectionState::CONNECTED) {
+    // Safety fallback - immediately complete
+    onComplete(true);
+    return;
+  }
+
+  // Handle connection failed state
+  if (state == WifiSelectionState::CONNECTION_FAILED) {
+    if (inputManager.wasPressed(InputManager::BTN_BACK) || inputManager.wasPressed(InputManager::BTN_CONFIRM)) {
+      // If we used saved credentials, offer to forget the network
+      if (usedSavedPassword) {
+        state = WifiSelectionState::FORGET_PROMPT;
+        forgetPromptSelection = 0;  // Default to "Yes"
+      } else {
+        // Go back to network list on failure
+        state = WifiSelectionState::NETWORK_LIST;
+      }
+      updateRequired = true;
+      return;
+    }
+  }
+
+  // Handle network list state
+  if (state == WifiSelectionState::NETWORK_LIST) {
+    // Check for Back button to exit (cancel)
+    if (inputManager.wasPressed(InputManager::BTN_BACK)) {
+      onComplete(false);
+      return;
+    }
+
+    // Check for Confirm button to select network or rescan
+    if (inputManager.wasPressed(InputManager::BTN_CONFIRM)) {
+      if (!networks.empty()) {
+        selectNetwork(selectedNetworkIndex);
+      } else {
+        startWifiScan();
+      }
+      return;
+    }
+
+    // Handle UP/DOWN navigation
+    if (inputManager.wasPressed(InputManager::BTN_UP) || inputManager.wasPressed(InputManager::BTN_LEFT)) {
+      if (selectedNetworkIndex > 0) {
+        selectedNetworkIndex--;
+        updateRequired = true;
+      }
+    } else if (inputManager.wasPressed(InputManager::BTN_DOWN) || inputManager.wasPressed(InputManager::BTN_RIGHT)) {
+      if (!networks.empty() && selectedNetworkIndex < static_cast<int>(networks.size()) - 1) {
+        selectedNetworkIndex++;
+        updateRequired = true;
+      }
+    }
+  }
+}
+
+std::string WifiSelectionActivity::getSignalStrengthIndicator(const int32_t rssi) const {
+  // Convert RSSI to signal bars representation
+  if (rssi >= -50) {
+    return "||||";  // Excellent
+  }
+  if (rssi >= -60) {
+    return "||| ";  // Good
+  }
+  if (rssi >= -70) {
+    return "||  ";  // Fair
+  }
+  if (rssi >= -80) {
+    return "|   ";  // Weak
+  }
+  return "    ";  // Very weak
+}
+
+void WifiSelectionActivity::displayTaskLoop() {
+  while (true) {
+    if (updateRequired) {
+      updateRequired = false;
+      xSemaphoreTake(renderingMutex, portMAX_DELAY);
+      render();
+      xSemaphoreGive(renderingMutex);
+    }
+    vTaskDelay(10 / portTICK_PERIOD_MS);
+  }
+}
+
+void WifiSelectionActivity::render() const {
+  renderer.clearScreen();
+
+  switch (state) {
+    case WifiSelectionState::SCANNING:
+      renderConnecting();  // Reuse connecting screen with different message
+      break;
+    case WifiSelectionState::NETWORK_LIST:
+      renderNetworkList();
+      break;
+    case WifiSelectionState::PASSWORD_ENTRY:
+      renderPasswordEntry();
+      break;
+    case WifiSelectionState::CONNECTING:
+      renderConnecting();
+      break;
+    case WifiSelectionState::CONNECTED:
+      renderConnected();
+      break;
+    case WifiSelectionState::SAVE_PROMPT:
+      renderSavePrompt();
+      break;
+    case WifiSelectionState::CONNECTION_FAILED:
+      renderConnectionFailed();
+      break;
+    case WifiSelectionState::FORGET_PROMPT:
+      renderForgetPrompt();
+      break;
+  }
+
+  renderer.displayBuffer();
+}
+
+void WifiSelectionActivity::renderNetworkList() const {
+  const auto pageWidth = renderer.getScreenWidth();
+  const auto pageHeight = renderer.getScreenHeight();
+
+  // Draw header
+  renderer.drawCenteredText(READER_FONT_ID, 10, "WiFi Networks", true, BOLD);
+
+  if (networks.empty()) {
+    // No networks found or scan failed
+    const auto height = renderer.getLineHeight(UI_FONT_ID);
+    const auto top = (pageHeight - height) / 2;
+    renderer.drawCenteredText(UI_FONT_ID, top, "No networks found", true, REGULAR);
+    renderer.drawCenteredText(SMALL_FONT_ID, top + height + 10, "Press OK to scan again", true, REGULAR);
+  } else {
+    // Calculate how many networks we can display
+    constexpr int startY = 60;
+    constexpr int lineHeight = 25;
+    const int maxVisibleNetworks = (pageHeight - startY - 40) / lineHeight;
+
+    // Calculate scroll offset to keep selected item visible
+    int scrollOffset = 0;
+    if (selectedNetworkIndex >= maxVisibleNetworks) {
+      scrollOffset = selectedNetworkIndex - maxVisibleNetworks + 1;
+    }
+
+    // Draw networks
+    int displayIndex = 0;
+    for (size_t i = scrollOffset; i < networks.size() && displayIndex < maxVisibleNetworks; i++, displayIndex++) {
+      const int networkY = startY + displayIndex * lineHeight;
+      const auto& network = networks[i];
+
+      // Draw selection indicator
+      if (static_cast<int>(i) == selectedNetworkIndex) {
+        renderer.drawText(UI_FONT_ID, 5, networkY, ">");
+      }
+
+      // Draw network name (truncate if too long)
+      std::string displayName = network.ssid;
+      if (displayName.length() > 16) {
+        displayName.replace(13, displayName.length() - 13, "...");
+      }
+      renderer.drawText(UI_FONT_ID, 20, networkY, displayName.c_str());
+
+      // Draw signal strength indicator
+      std::string signalStr = getSignalStrengthIndicator(network.rssi);
+      renderer.drawText(UI_FONT_ID, pageWidth - 90, networkY, signalStr.c_str());
+
+      // Draw saved indicator (checkmark) for networks with saved passwords
+      if (network.hasSavedPassword) {
+        renderer.drawText(UI_FONT_ID, pageWidth - 50, networkY, "+");
+      }
+
+      // Draw lock icon for encrypted networks
+      if (network.isEncrypted) {
+        renderer.drawText(UI_FONT_ID, pageWidth - 30, networkY, "*");
+      }
+    }
+
+    // Draw scroll indicators if needed
+    if (scrollOffset > 0) {
+      renderer.drawText(SMALL_FONT_ID, pageWidth - 15, startY - 10, "^");
+    }
+    if (scrollOffset + maxVisibleNetworks < static_cast<int>(networks.size())) {
+      renderer.drawText(SMALL_FONT_ID, pageWidth - 15, startY + maxVisibleNetworks * lineHeight, "v");
+    }
+
+    // Show network count
+    char countStr[32];
+    snprintf(countStr, sizeof(countStr), "%zu networks found", networks.size());
+    renderer.drawText(SMALL_FONT_ID, 20, pageHeight - 45, countStr);
+  }
+
+  // Draw help text
+  renderer.drawText(SMALL_FONT_ID, 20, pageHeight - 30, "OK: Connect | * = Encrypted | + = Saved");
+}
+
+void WifiSelectionActivity::renderPasswordEntry() const {
+  // 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.replace(27, networkInfo.length() - 27, "...");
+  }
+  renderer.drawCenteredText(UI_FONT_ID, 38, networkInfo.c_str(), true, REGULAR);
+
+  // Draw keyboard
+  if (subActivity) {
+    static_cast<KeyboardEntryActivity*>(subActivity.get())->render(58);
+  }
+}
+
+void WifiSelectionActivity::renderConnecting() const {
+  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);
+
+    std::string ssidInfo = "to " + selectedSSID;
+    if (ssidInfo.length() > 25) {
+      ssidInfo.replace(22, ssidInfo.length() - 22, "...");
+    }
+    renderer.drawCenteredText(UI_FONT_ID, top, ssidInfo.c_str(), true, REGULAR);
+  }
+}
+
+void WifiSelectionActivity::renderConnected() const {
+  const auto pageHeight = renderer.getScreenHeight();
+  const auto height = renderer.getLineHeight(UI_FONT_ID);
+  const auto top = (pageHeight - height * 4) / 2;
+
+  renderer.drawCenteredText(READER_FONT_ID, top - 30, "Connected!", true, BOLD);
+
+  std::string ssidInfo = "Network: " + selectedSSID;
+  if (ssidInfo.length() > 28) {
+    ssidInfo.replace(25, ssidInfo.length() - 25, "...");
+  }
+  renderer.drawCenteredText(UI_FONT_ID, top + 10, ssidInfo.c_str(), true, REGULAR);
+
+  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 = renderer.getScreenWidth();
+  const auto pageHeight = renderer.getScreenHeight();
+  const auto height = renderer.getLineHeight(UI_FONT_ID);
+  const auto top = (pageHeight - height * 3) / 2;
+
+  renderer.drawCenteredText(READER_FONT_ID, top - 40, "Connected!", true, BOLD);
+
+  std::string ssidInfo = "Network: " + selectedSSID;
+  if (ssidInfo.length() > 28) {
+    ssidInfo.replace(25, ssidInfo.length() - 25, "...");
+  }
+  renderer.drawCenteredText(UI_FONT_ID, top, ssidInfo.c_str(), true, REGULAR);
+
+  renderer.drawCenteredText(UI_FONT_ID, top + 40, "Save password for next time?", true, REGULAR);
+
+  // Draw Yes/No buttons
+  const int buttonY = top + 80;
+  constexpr int buttonWidth = 60;
+  constexpr int buttonSpacing = 30;
+  constexpr int totalWidth = buttonWidth * 2 + buttonSpacing;
+  const int startX = (pageWidth - totalWidth) / 2;
+
+  // Draw "Yes" button
+  if (savePromptSelection == 0) {
+    renderer.drawText(UI_FONT_ID, startX, buttonY, "[Yes]");
+  } else {
+    renderer.drawText(UI_FONT_ID, startX + 4, buttonY, "Yes");
+  }
+
+  // Draw "No" button
+  if (savePromptSelection == 1) {
+    renderer.drawText(UI_FONT_ID, startX + buttonWidth + buttonSpacing, buttonY, "[No]");
+  } else {
+    renderer.drawText(UI_FONT_ID, startX + buttonWidth + buttonSpacing + 4, buttonY, "No");
+  }
+
+  renderer.drawCenteredText(SMALL_FONT_ID, pageHeight - 30, "LEFT/RIGHT: Select | OK: Confirm", true, REGULAR);
+}
+
+void WifiSelectionActivity::renderConnectionFailed() const {
+  const auto pageHeight = renderer.getScreenHeight();
+  const auto height = renderer.getLineHeight(UI_FONT_ID);
+  const auto top = (pageHeight - height * 2) / 2;
+
+  renderer.drawCenteredText(READER_FONT_ID, top - 20, "Connection Failed", true, BOLD);
+  renderer.drawCenteredText(UI_FONT_ID, top + 20, connectionError.c_str(), true, REGULAR);
+  renderer.drawCenteredText(SMALL_FONT_ID, pageHeight - 30, "Press any button to continue", true, REGULAR);
+}
+
+void WifiSelectionActivity::renderForgetPrompt() const {
+  const auto pageWidth = renderer.getScreenWidth();
+  const auto pageHeight = renderer.getScreenHeight();
+  const auto height = renderer.getLineHeight(UI_FONT_ID);
+  const auto top = (pageHeight - height * 3) / 2;
+
+  renderer.drawCenteredText(READER_FONT_ID, top - 40, "Forget Network?", true, BOLD);
+
+  std::string ssidInfo = "Network: " + selectedSSID;
+  if (ssidInfo.length() > 28) {
+    ssidInfo.replace(25, ssidInfo.length() - 25, "...");
+  }
+  renderer.drawCenteredText(UI_FONT_ID, top, ssidInfo.c_str(), true, REGULAR);
+
+  renderer.drawCenteredText(UI_FONT_ID, top + 40, "Remove saved password?", true, REGULAR);
+
+  // Draw Yes/No buttons
+  const int buttonY = top + 80;
+  constexpr int buttonWidth = 60;
+  constexpr int buttonSpacing = 30;
+  constexpr int totalWidth = buttonWidth * 2 + buttonSpacing;
+  const int startX = (pageWidth - totalWidth) / 2;
+
+  // Draw "Yes" button
+  if (forgetPromptSelection == 0) {
+    renderer.drawText(UI_FONT_ID, startX, buttonY, "[Yes]");
+  } else {
+    renderer.drawText(UI_FONT_ID, startX + 4, buttonY, "Yes");
+  }
+
+  // Draw "No" button
+  if (forgetPromptSelection == 1) {
+    renderer.drawText(UI_FONT_ID, startX + buttonWidth + buttonSpacing, buttonY, "[No]");
+  } else {
+    renderer.drawText(UI_FONT_ID, startX + buttonWidth + buttonSpacing + 4, buttonY, "No");
+  }
+
+  renderer.drawCenteredText(SMALL_FONT_ID, pageHeight - 30, "LEFT/RIGHT: Select | OK: Confirm", true, REGULAR);
+}

src/activities/network/WifiSelectionActivity.h

@@ -0,0 +1,104 @@
+#pragma once
+#include <freertos/FreeRTOS.h>
+#include <freertos/semphr.h>
+#include <freertos/task.h>
+
+#include <cstdint>
+#include <functional>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "activities/ActivityWithSubactivity.h"
+
+// Structure to hold WiFi network information
+struct WifiNetworkInfo {
+  std::string ssid;
+  int32_t rssi;
+  bool isEncrypted;
+  bool hasSavedPassword;  // Whether we have saved credentials for this network
+};
+
+// WiFi selection states
+enum class WifiSelectionState {
+  SCANNING,           // Scanning for networks
+  NETWORK_LIST,       // Displaying available networks
+  PASSWORD_ENTRY,     // Entering password for selected network
+  CONNECTING,         // Attempting to connect
+  CONNECTED,          // Successfully connected
+  SAVE_PROMPT,        // Asking user if they want to save the password
+  CONNECTION_FAILED,  // Connection failed
+  FORGET_PROMPT       // Asking user if they want to forget the network
+};
+
+/**
+ * WifiSelectionActivity is responsible for scanning WiFi APs and connecting to them.
+ * It will:
+ * - Enter scanning mode on entry
+ * - List available WiFi networks
+ * - Allow selection and launch KeyboardEntryActivity for password if needed
+ * - Save the password if requested
+ * - Call onComplete callback when connected or cancelled
+ *
+ * The onComplete callback receives true if connected successfully, false if cancelled.
+ */
+class WifiSelectionActivity final : public ActivityWithSubactivity {
+  TaskHandle_t displayTaskHandle = nullptr;
+  SemaphoreHandle_t renderingMutex = nullptr;
+  bool updateRequired = false;
+  WifiSelectionState state = WifiSelectionState::SCANNING;
+  int selectedNetworkIndex = 0;
+  std::vector<WifiNetworkInfo> networks;
+  const std::function<void(bool connected)> onComplete;
+
+  // Selected network for connection
+  std::string selectedSSID;
+  bool selectedRequiresPassword = false;
+
+  // Connection result
+  std::string connectedIP;
+  std::string connectionError;
+
+  // Password to potentially save (from keyboard or saved credentials)
+  std::string enteredPassword;
+
+  // Whether network was connected using a saved password (skip save prompt)
+  bool usedSavedPassword = false;
+
+  // Save/forget prompt selection (0 = Yes, 1 = No)
+  int savePromptSelection = 0;
+  int forgetPromptSelection = 0;
+
+  // Connection timeout
+  static constexpr unsigned long CONNECTION_TIMEOUT_MS = 15000;
+  unsigned long connectionStartTime = 0;
+
+  static void taskTrampoline(void* param);
+  [[noreturn]] void displayTaskLoop();
+  void render() const;
+  void renderNetworkList() const;
+  void renderPasswordEntry() const;
+  void renderConnecting() const;
+  void renderConnected() const;
+  void renderSavePrompt() const;
+  void renderConnectionFailed() const;
+  void renderForgetPrompt() const;
+
+  void startWifiScan();
+  void processWifiScanResults();
+  void selectNetwork(int index);
+  void attemptConnection();
+  void checkConnectionStatus();
+  std::string getSignalStrengthIndicator(int32_t rssi) const;
+
+ public:
+  explicit WifiSelectionActivity(GfxRenderer& renderer, InputManager& inputManager,
+                                 const std::function<void(bool connected)>& onComplete)
+      : ActivityWithSubactivity("WifiSelection", renderer, inputManager), onComplete(onComplete) {}
+  void onEnter() override;
+  void onExit() override;
+  void loop() override;
+
+  // Get the IP address after successful connection
+  const std::string& getConnectedIP() const { return connectedIP; }
+};

src/activities/reader/EpubReaderActivity.cpp

@@ -1,11 +1,13 @@
 #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"
 
@@ -25,6 +27,8 @@ void EpubReaderActivity::taskTrampoline(void* param) {
 }
 
 void EpubReaderActivity::onEnter() {
+  ActivityWithSubactivity::onEnter();
+
   if (!epub) {
     return;
   }
@@ -33,16 +37,21 @@ void EpubReaderActivity::onEnter() {
 
   epub->setupCacheDir();
 
-  if (SD.exists((epub->getCachePath() + "/progress.bin").c_str())) {
-    File f = SD.open((epub->getCachePath() + "/progress.bin").c_str());
+  File f;
+  if (FsHelpers::openFileForRead("ERS", epub->getCachePath() + "/progress.bin", f)) {
     uint8_t data[4];
-    f.read(data, 4);
-    currentSpineIndex = data[0] + (data[1] << 8);
-    nextPageNumber = data[2] + (data[3] << 8);
-    Serial.printf("[%lu] [ERS] Loaded cache: %d, %d\n", millis(), currentSpineIndex, nextPageNumber);
+    if (f.read(data, 4) == 4) {
+      currentSpineIndex = data[0] + (data[1] << 8);
+      nextPageNumber = data[2] + (data[3] << 8);
+      Serial.printf("[%lu] [ERS] Loaded cache: %d, %d\n", millis(), currentSpineIndex, nextPageNumber);
+    }
     f.close();
   }
 
+  // Save current epub as last opened epub
+  APP_STATE.openEpubPath = epub->getPath();
+  APP_STATE.saveToFile();
+
   // Trigger first update
   updateRequired = true;
 
@@ -55,6 +64,8 @@ void EpubReaderActivity::onEnter() {
 }
 
 void EpubReaderActivity::onExit() {
+  ActivityWithSubactivity::onExit();
+
   // Wait until not rendering to delete task to avoid killing mid-instruction to EPD
   xSemaphoreTake(renderingMutex, portMAX_DELAY);
   if (displayTaskHandle) {
@@ -69,8 +80,8 @@ void EpubReaderActivity::onExit() {
 
 void EpubReaderActivity::loop() {
   // Pass input responsibility to sub activity if exists
-  if (subAcitivity) {
-    subAcitivity->loop();
+  if (subActivity) {
+    subActivity->loop();
     return;
   }
 
@@ -78,11 +89,11 @@ 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();
-          subAcitivity.reset();
+          exitActivity();
           updateRequired = true;
         },
         [this](const int newSpineIndex) {
@@ -91,11 +102,9 @@ void EpubReaderActivity::loop() {
             nextPageNumber = 0;
             section.reset();
           }
-          subAcitivity->onExit();
-          subAcitivity.reset();
+          exitActivity();
           updateRequired = true;
         }));
-    subAcitivity->onEnter();
     xSemaphoreGive(renderingMutex);
   }
 
@@ -203,7 +212,7 @@ 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,
@@ -213,12 +222,11 @@ void EpubReaderActivity::renderScreen() {
       {
         const int textWidth = renderer.getTextWidth(READER_FONT_ID, "Indexing...");
         constexpr int margin = 20;
-        // Round all coordinates to 8 pixel boundaries
-        const int x = ((GfxRenderer::getScreenWidth() - textWidth - margin * 2) / 2 + 7) / 8 * 8;
-        constexpr int y = 56;
-        const int w = (textWidth + margin * 2 + 7) / 8 * 8;
-        const int h = (renderer.getLineHeight(READER_FONT_ID) + margin * 2 + 7) / 8 * 8;
-        renderer.clearScreen();
+        const int x = (GfxRenderer::getScreenWidth() - textWidth - margin * 2) / 2;
+        constexpr int y = 50;
+        const int w = textWidth + margin * 2;
+        const int h = renderer.getLineHeight(READER_FONT_ID) + margin * 2;
+        renderer.fillRect(x, y, w, h, false);
         renderer.drawText(READER_FONT_ID, x + margin, y + margin, "Indexing...");
         renderer.drawRect(x + 5, y + 5, w - 10, h - 10);
         renderer.displayBuffer();
@@ -274,14 +282,16 @@ 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);
-  uint8_t data[4];
-  data[0] = currentSpineIndex & 0xFF;
-  data[1] = (currentSpineIndex >> 8) & 0xFF;
-  data[2] = section->currentPage & 0xFF;
-  data[3] = (section->currentPage >> 8) & 0xFF;
-  f.write(data, 4);
-  f.close();
+  File f;
+  if (FsHelpers::openFileForWrite("ERS", epub->getCachePath() + "/progress.bin", f)) {
+    uint8_t data[4];
+    data[0] = currentSpineIndex & 0xFF;
+    data[1] = (currentSpineIndex >> 8) & 0xFF;
+    data[2] = section->currentPage & 0xFF;
+    data[3] = (section->currentPage >> 8) & 0xFF;
+    f.write(data, 4);
+    f.close();
+  }
 }
 
 void EpubReaderActivity::renderContents(std::unique_ptr<Page> page) {
@@ -325,8 +335,8 @@ void EpubReaderActivity::renderStatusBar() const {
   constexpr auto textY = 776;
 
   // Calculate progress in book
-  float sectionChapterProg = static_cast<float>(section->currentPage) / section->pageCount;
-  uint8_t bookProgress = epub->calculateProgress(currentSpineIndex, sectionChapterProg);
+  const float sectionChapterProg = static_cast<float>(section->currentPage) / section->pageCount;
+  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) +
@@ -382,8 +392,8 @@ void EpubReaderActivity::renderStatusBar() const {
     const auto tocItem = epub->getTocItem(tocIndex);
     title = tocItem.title;
     titleWidth = renderer.getTextWidth(SMALL_FONT_ID, title.c_str());
-    while (titleWidth > availableTextWidth) {
-      title = title.substr(0, title.length() - 8) + "...";
+    while (titleWidth > availableTextWidth && title.length() > 11) {
+      title.replace(title.length() - 8, 8, "...");
       titleWidth = renderer.getTextWidth(SMALL_FONT_ID, title.c_str());
     }
   }

src/activities/reader/EpubReaderActivity.h

@@ -5,14 +5,13 @@
 #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;
@@ -28,7 +27,7 @@ class EpubReaderActivity final : public Activity {
  public:
   explicit EpubReaderActivity(GfxRenderer& renderer, InputManager& inputManager, std::unique_ptr<Epub> epub,
                               const std::function<void()>& onGoBack)
-      : Activity(renderer, inputManager), epub(std::move(epub)), onGoBack(onGoBack) {}
+      : ActivityWithSubactivity("EpubReader", renderer, inputManager), epub(std::move(epub)), onGoBack(onGoBack) {}
   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 {
 constexpr int PAGE_ITEMS = 24;
 constexpr int SKIP_PAGE_MS = 700;
+}  // namespace
 
 void EpubReaderChapterSelectionActivity::taskTrampoline(void* param) {
   auto* self = static_cast<EpubReaderChapterSelectionActivity*>(param);
@@ -14,6 +17,8 @@ void EpubReaderChapterSelectionActivity::taskTrampoline(void* param) {
 }
 
 void EpubReaderChapterSelectionActivity::onEnter() {
+  Activity::onEnter();
+
   if (!epub) {
     return;
   }
@@ -24,7 +29,7 @@ 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
@@ -32,6 +37,8 @@ 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) {

src/activities/reader/EpubReaderChapterSelectionActivity.h

@@ -27,7 +27,7 @@ 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 +1,16 @@
 #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;
+}  // 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;
@@ -43,6 +49,8 @@ void FileSelectionActivity::loadFiles() {
 }
 
 void FileSelectionActivity::onEnter() {
+  Activity::onEnter();
+
   renderingMutex = xSemaphoreCreateMutex();
 
   basepath = "/";
@@ -61,6 +69,8 @@ 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 +83,12 @@ void FileSelectionActivity::onExit() {
 }
 
 void FileSelectionActivity::loop() {
-  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);
+  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()) {
@@ -93,7 +105,7 @@ void FileSelectionActivity::loop() {
     }
   } else if (inputManager.wasPressed(InputManager::BTN_BACK)) {
     if (basepath != "/") {
-      basepath = basepath.substr(0, basepath.rfind('/'));
+      basepath.replace(basepath.find_last_of('/'), std::string::npos, "");
       if (basepath.empty()) basepath = "/";
       loadFiles();
       updateRequired = true;
@@ -101,11 +113,19 @@ void FileSelectionActivity::loop() {
       // At root level, go back home
       onGoHome();
     }
-  } else if (prevPressed) {
-    selectorIndex = (selectorIndex + files.size() - 1) % files.size();
+  } 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) {
-    selectorIndex = (selectorIndex + 1) % files.size();
+  } else if (nextReleased) {
+    if (skipPage) {
+      selectorIndex = ((selectorIndex / PAGE_ITEMS + 1) * PAGE_ITEMS) % files.size();
+    } else {
+      selectorIndex = (selectorIndex + 1) % files.size();
+    }
     updateRequired = true;
   }
 }
@@ -126,21 +146,27 @@ 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");
 
   if (files.empty()) {
     renderer.drawText(UI_FONT_ID, 20, 60, "No EPUBs found");
-  } else {
-    // Draw selection
-    renderer.fillRect(0, 60 + selectorIndex * 30 + 2, pageWidth - 1, 30);
+    renderer.displayBuffer();
+    return;
+  }
 
-    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

@@ -28,7 +28,7 @@ class FileSelectionActivity final : public Activity {
   explicit FileSelectionActivity(GfxRenderer& renderer, InputManager& inputManager,
                                  const std::function<void(const std::string&)>& onSelect,
                                  const std::function<void()>& onGoHome)
-      : Activity(renderer, inputManager), onSelect(onSelect), onGoHome(onGoHome) {}
+      : Activity("FileSelection", renderer, inputManager), onSelect(onSelect), onGoHome(onGoHome) {}
   void onEnter() override;
   void onExit() override;
   void loop() override;

src/activities/reader/ReaderActivity.cpp

@@ -2,7 +2,6 @@
 
 #include <SD.h>
 
-#include "CrossPointState.h"
 #include "Epub.h"
 #include "EpubReaderActivity.h"
 #include "FileSelectionActivity.h"
@@ -29,8 +28,6 @@ void ReaderActivity::onSelectEpubFile(const std::string& path) {
 
   auto epub = loadEpub(path);
   if (epub) {
-    APP_STATE.openEpubPath = path;
-    APP_STATE.saveToFile();
     onGoToEpubReader(std::move(epub));
   } else {
     exitActivity();
@@ -53,6 +50,8 @@ void ReaderActivity::onGoToEpubReader(std::unique_ptr<Epub> epub) {
 }
 
 void ReaderActivity::onEnter() {
+  ActivityWithSubactivity::onEnter();
+
   if (initialEpubPath.empty()) {
     onGoToFileSelection();
     return;

src/activities/reader/ReaderActivity.h

@@ -17,7 +17,7 @@ class ReaderActivity final : public ActivityWithSubactivity {
  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

@@ -1,15 +1,23 @@
 #include "SettingsActivity.h"
 
 #include <GfxRenderer.h>
+#include <InputManager.h>
 
 #include "CrossPointSettings.h"
+#include "OtaUpdateActivity.h"
 #include "config.h"
 
 // Define the static settings list
-
-const SettingInfo SettingsActivity::settingsList[settingsCount] = {
-    {"White Sleep Screen", &CrossPointSettings::whiteSleepScreen},
-    {"Extra Paragraph Spacing", &CrossPointSettings::extraParagraphSpacing}};
+namespace {
+constexpr int settingsCount = 4;
+const SettingInfo settingsList[settingsCount] = {
+    // Should match with SLEEP_SCREEN_MODE
+    {"Sleep Screen", SettingType::ENUM, &CrossPointSettings::sleepScreen, {"Dark", "Light", "Custom", "Cover"}},
+    {"Extra Paragraph Spacing", SettingType::TOGGLE, &CrossPointSettings::extraParagraphSpacing, {}},
+    {"Short Power Button Click", SettingType::TOGGLE, &CrossPointSettings::shortPwrBtn, {}},
+    {"Check for updates", SettingType::ACTION, nullptr, {}},
+};
+}  // namespace
 
 void SettingsActivity::taskTrampoline(void* param) {
   auto* self = static_cast<SettingsActivity*>(param);
@@ -17,6 +25,8 @@ void SettingsActivity::taskTrampoline(void* param) {
 }
 
 void SettingsActivity::onEnter() {
+  Activity::onEnter();
+
   renderingMutex = xSemaphoreCreateMutex();
 
   // Reset selection to first item
@@ -34,6 +44,8 @@ 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) {
@@ -45,6 +57,11 @@ void SettingsActivity::onExit() {
 }
 
 void SettingsActivity::loop() {
+  if (subActivity) {
+    subActivity->loop();
+    return;
+  }
+
   // Handle actions with early return
   if (inputManager.wasPressed(InputManager::BTN_CONFIRM)) {
     toggleCurrentSetting();
@@ -64,9 +81,11 @@ void SettingsActivity::loop() {
     selectedSettingIndex = (selectedSettingIndex > 0) ? (selectedSettingIndex - 1) : (settingsCount - 1);
     updateRequired = true;
   } else if (inputManager.wasPressed(InputManager::BTN_DOWN) || inputManager.wasPressed(InputManager::BTN_RIGHT)) {
-    // Move selection down (with wrap-around)
-    selectedSettingIndex = (selectedSettingIndex < settingsCount - 1) ? (selectedSettingIndex + 1) : 0;
-    updateRequired = true;
+    // Move selection down
+    if (selectedSettingIndex < settingsCount - 1) {
+      selectedSettingIndex++;
+      updateRequired = true;
+    }
   }
 }
 
@@ -76,9 +95,29 @@ void SettingsActivity::toggleCurrentSetting() {
     return;
   }
 
-  // Toggle the boolean value using the member pointer
-  bool currentValue = SETTINGS.*(settingsList[selectedSettingIndex].valuePtr);
-  SETTINGS.*(settingsList[selectedSettingIndex].valuePtr) = !currentValue;
+  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
+    return;
+  }
 
   // Save settings when they change
   SETTINGS.saveToFile();
@@ -86,7 +125,7 @@ void SettingsActivity::toggleCurrentSetting() {
 
 void SettingsActivity::displayTaskLoop() {
   while (true) {
-    if (updateRequired) {
+    if (updateRequired && !subActivity) {
       updateRequired = false;
       xSemaphoreTake(renderingMutex, portMAX_DELAY);
       render();
@@ -105,8 +144,6 @@ void SettingsActivity::render() const {
   // Draw header
   renderer.drawCenteredText(READER_FONT_ID, 10, "Settings", true, BOLD);
 
-  // We always have at least one setting
-
   // Draw all settings
   for (int i = 0; i < settingsCount; i++) {
     const int settingY = 60 + i * 30;  // 30 pixels between settings
@@ -116,14 +153,25 @@ void SettingsActivity::render() const {
       renderer.drawText(UI_FONT_ID, 5, settingY, ">");
     }
 
-    // Draw setting name and value
+    // Draw setting name
     renderer.drawText(UI_FONT_ID, 20, settingY, settingsList[i].name);
-    bool value = SETTINGS.*(settingsList[i].valuePtr);
-    renderer.drawText(UI_FONT_ID, pageWidth - 80, settingY, value ? "ON" : "OFF");
+
+    // Draw value based on setting type
+    if (settingsList[i].type == SettingType::TOGGLE && settingsList[i].valuePtr != nullptr) {
+      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.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

@@ -3,31 +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, ACTION };
+
 // Structure to hold setting information
 struct SettingInfo {
   const char* name;                        // Display name of the setting
-  uint8_t CrossPointSettings::* valuePtr;  // Pointer to member in CrossPointSettings
+  SettingType type;                        // Type of setting
+  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 = 2;  // Number of settings
-  static const SettingInfo settingsList[settingsCount];
-
   static void taskTrampoline(void* param);
   [[noreturn]] void displayTaskLoop();
   void render() const;
@@ -35,7 +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

@@ -0,0 +1,308 @@
+#include "KeyboardEntryActivity.h"
+
+#include "../../config.h"
+
+// Keyboard layouts - lowercase
+const char* const KeyboardEntryActivity::keyboard[NUM_ROWS] = {
+    "`1234567890-=", "qwertyuiop[]\\", "asdfghjkl;'", "zxcvbnm,./",
+    "^  _____<OK"  // ^ = shift, _ = space, < = backspace, OK = done
+};
+
+// Keyboard layouts - uppercase/symbols
+const char* const KeyboardEntryActivity::keyboardShift[NUM_ROWS] = {"~!@#$%^&*()_+", "QWERTYUIOP{}|", "ASDFGHJKL:\"",
+                                                                    "ZXCVBNM<>?", "^  _____<OK"};
+
+void KeyboardEntryActivity::setText(const std::string& newText) {
+  text = newText;
+  if (maxLength > 0 && text.length() > maxLength) {
+    text.resize(maxLength);
+  }
+}
+
+void KeyboardEntryActivity::reset(const std::string& newTitle, const std::string& newInitialText) {
+  if (!newTitle.empty()) {
+    title = newTitle;
+  }
+  text = newInitialText;
+  selectedRow = 0;
+  selectedCol = 0;
+  shiftActive = false;
+  complete = false;
+  cancelled = false;
+}
+
+void KeyboardEntryActivity::onEnter() {
+  Activity::onEnter();
+
+  // Reset state when entering the activity
+  complete = false;
+  cancelled = false;
+}
+
+void KeyboardEntryActivity::loop() {
+  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
+  switch (row) {
+    case 0:
+      return 13;  // `1234567890-=
+    case 1:
+      return 13;  // qwertyuiop[]backslash
+    case 2:
+      return 11;  // asdfghjkl;'
+    case 3:
+      return 10;  // zxcvbnm,./
+    case 4:
+      return 10;  // ^, space (5 wide), backspace, OK (2 wide)
+    default:
+      return 0;
+  }
+}
+
+char KeyboardEntryActivity::getSelectedChar() const {
+  const char* const* layout = shiftActive ? keyboardShift : keyboard;
+
+  if (selectedRow < 0 || selectedRow >= NUM_ROWS) return '\0';
+  if (selectedCol < 0 || selectedCol >= getRowLength(selectedRow)) return '\0';
+
+  return layout[selectedRow][selectedCol];
+}
+
+void KeyboardEntryActivity::handleKeyPress() {
+  // Handle special row (bottom row with shift, space, backspace, done)
+  if (selectedRow == SHIFT_ROW) {
+    if (selectedCol == SHIFT_COL) {
+      // Shift toggle
+      shiftActive = !shiftActive;
+      return;
+    }
+
+    if (selectedCol >= SPACE_COL && selectedCol < BACKSPACE_COL) {
+      // Space bar
+      if (maxLength == 0 || text.length() < maxLength) {
+        text += ' ';
+      }
+      return;
+    }
+
+    if (selectedCol == BACKSPACE_COL) {
+      // Backspace
+      if (!text.empty()) {
+        text.pop_back();
+      }
+      return;
+    }
+
+    if (selectedCol >= DONE_COL) {
+      // Done button
+      complete = true;
+      if (onComplete) {
+        onComplete(text);
+      }
+      return;
+    }
+  }
+
+  // Regular character
+  char c = getSelectedChar();
+  if (c != '\0' && c != '^' && c != '_' && c != '<') {
+    if (maxLength == 0 || text.length() < maxLength) {
+      text += c;
+      // Auto-disable shift after typing a letter
+      if (shiftActive && ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z'))) {
+        shiftActive = false;
+      }
+    }
+  }
+}
+
+bool KeyboardEntryActivity::handleInput() {
+  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;
+      if (selectedCol > maxCol) selectedCol = maxCol;
+    }
+    handled = true;
+  } else if (inputManager.wasPressed(InputManager::BTN_DOWN)) {
+    if (selectedRow < NUM_ROWS - 1) {
+      selectedRow++;
+      int maxCol = getRowLength(selectedRow) - 1;
+      if (selectedCol > maxCol) selectedCol = maxCol;
+    }
+    handled = true;
+  } else if (inputManager.wasPressed(InputManager::BTN_LEFT)) {
+    if (selectedCol > 0) {
+      selectedCol--;
+    } else if (selectedRow > 0) {
+      // Wrap to previous row
+      selectedRow--;
+      selectedCol = getRowLength(selectedRow) - 1;
+    }
+    handled = true;
+  } else if (inputManager.wasPressed(InputManager::BTN_RIGHT)) {
+    int maxCol = getRowLength(selectedRow) - 1;
+    if (selectedCol < maxCol) {
+      selectedCol++;
+    } else if (selectedRow < NUM_ROWS - 1) {
+      // Wrap to next row
+      selectedRow++;
+      selectedCol = 0;
+    }
+    handled = true;
+  }
+
+  // Selection
+  if (inputManager.wasPressed(InputManager::BTN_CONFIRM)) {
+    handleKeyPress();
+    handled = true;
+  }
+
+  // Cancel
+  if (inputManager.wasPressed(InputManager::BTN_BACK)) {
+    cancelled = true;
+    if (onCancel) {
+      onCancel();
+    }
+    handled = true;
+  }
+
+  return handled;
+}
+
+void KeyboardEntryActivity::render(int startY) const {
+  const auto pageWidth = GfxRenderer::getScreenWidth();
+
+  // Draw title
+  renderer.drawCenteredText(UI_FONT_ID, startY, title.c_str(), true, REGULAR);
+
+  // Draw input field
+  int inputY = startY + 22;
+  renderer.drawText(UI_FONT_ID, 10, inputY, "[");
+
+  std::string displayText;
+  if (isPassword) {
+    displayText = std::string(text.length(), '*');
+  } else {
+    displayText = text;
+  }
+
+  // Show cursor at end
+  displayText += "_";
+
+  // Truncate if too long for display - use actual character width from font
+  int charWidth = renderer.getSpaceWidth(UI_FONT_ID);
+  if (charWidth < 1) charWidth = 8;  // Fallback to approximate width
+  int maxDisplayLen = (pageWidth - 40) / charWidth;
+  if (displayText.length() > static_cast<size_t>(maxDisplayLen)) {
+    displayText = "..." + displayText.substr(displayText.length() - maxDisplayLen + 3);
+  }
+
+  renderer.drawText(UI_FONT_ID, 20, inputY, displayText.c_str());
+  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 keyWidth = 18;
+  const int keyHeight = 18;
+  const 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);
+  int leftMargin = (pageWidth - maxRowWidth) / 2;
+
+  for (int row = 0; row < NUM_ROWS; row++) {
+    int rowY = keyboardStartY + row * (keyHeight + keySpacing);
+
+    // Left-align all rows for consistent navigation
+    int startX = leftMargin;
+
+    // Handle bottom row (row 4) specially with proper multi-column keys
+    if (row == 4) {
+      // Bottom row layout: CAPS (2 cols) | SPACE (5 cols) | <- (2 cols) | OK (2 cols)
+      // Total: 11 visual columns, but we use logical positions for selection
+
+      int currentX = startX;
+
+      // CAPS key (logical col 0, spans 2 key widths)
+      int capsWidth = 2 * keyWidth + keySpacing;
+      bool capsSelected = (selectedRow == 4 && selectedCol == SHIFT_COL);
+      if (capsSelected) {
+        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;
+      bool spaceSelected = (selectedRow == 4 && selectedCol >= SPACE_COL && selectedCol < BACKSPACE_COL);
+      if (spaceSelected) {
+        renderer.drawText(UI_FONT_ID, currentX - 2, rowY, "[");
+        renderer.drawText(UI_FONT_ID, currentX + spaceWidth - 4, rowY, "]");
+      }
+      // 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;
+      bool bsSelected = (selectedRow == 4 && selectedCol == BACKSPACE_COL);
+      if (bsSelected) {
+        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;
+      bool okSelected = (selectedRow == 4 && selectedCol >= DONE_COL);
+      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];
+        std::string keyLabel(1, c);
+
+        // Draw selection highlight
+        bool isSelected = (row == selectedRow && col == selectedCol);
+
+        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());
+      }
+    }
+  }
+
+  // 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");
+}

src/activities/util/KeyboardEntryActivity.h

@@ -0,0 +1,131 @@
+#pragma once
+#include <GfxRenderer.h>
+#include <InputManager.h>
+
+#include <functional>
+#include <string>
+
+#include "../Activity.h"
+
+/**
+ * Reusable keyboard entry activity for text input.
+ * Can be started from any activity that needs text entry.
+ *
+ * Usage:
+ *   1. Create a KeyboardEntryActivity instance
+ *   2. Set callbacks with setOnComplete() and setOnCancel()
+ *   3. Call onEnter() to start the activity
+ *   4. Call loop() in your main loop
+ *   5. When complete or cancelled, callbacks will be invoked
+ */
+class KeyboardEntryActivity : public Activity {
+ public:
+  // Callback types
+  using OnCompleteCallback = std::function<void(const std::string&)>;
+  using OnCancelCallback = std::function<void()>;
+
+  /**
+   * Constructor
+   * @param renderer Reference to the GfxRenderer for drawing
+   * @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 maxLength Maximum length of input text (0 for unlimited)
+   * @param isPassword If true, display asterisks instead of actual characters
+   */
+  KeyboardEntryActivity(GfxRenderer& renderer, InputManager& inputManager, const std::string& title = "Enter Text",
+                        const std::string& initialText = "", const size_t maxLength = 0, const bool isPassword = false)
+      : Activity("KeyboardEntry", renderer, inputManager),
+        title(title),
+        text(initialText),
+        maxLength(maxLength),
+        isPassword(isPassword) {}
+
+  /**
+   * Handle button input. Call this in your main loop.
+   * @return true if input was handled, false otherwise
+   */
+  bool handleInput();
+
+  /**
+   * Render the keyboard at the specified Y position.
+   * @param startY Y-coordinate where keyboard rendering starts (default 10)
+   */
+  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;
+  void loop() override;
+
+ private:
+  std::string title;
+  std::string text;
+  size_t maxLength;
+  bool isPassword;
+
+  // Keyboard state
+  int selectedRow = 0;
+  int selectedCol = 0;
+  bool shiftActive = false;
+  bool complete = false;
+  bool cancelled = false;
+
+  // Callbacks
+  OnCompleteCallback onComplete;
+  OnCancelCallback onCancel;
+
+  // Keyboard layout
+  static constexpr int NUM_ROWS = 5;
+  static constexpr int KEYS_PER_ROW = 13;  // Max keys per row (rows 0 and 1 have 13 keys)
+  static const char* const keyboard[NUM_ROWS];
+  static const char* const keyboardShift[NUM_ROWS];
+
+  // Special key positions (bottom row)
+  static constexpr int SHIFT_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;
+
+  char getSelectedChar() const;
+  void handleKeyPress();
+  int getRowLength(int row) 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/main.cpp

@@ -19,6 +19,7 @@
 #include "activities/boot_sleep/BootActivity.h"
 #include "activities/boot_sleep/SleepActivity.h"
 #include "activities/home/HomeActivity.h"
+#include "activities/network/CrossPointWebServerActivity.h"
 #include "activities/reader/ReaderActivity.h"
 #include "activities/settings/SettingsActivity.h"
 #include "activities/util/FullScreenMessageActivity.h"
@@ -57,18 +58,17 @@ EpdFont ubuntu10Font(&ubuntu_10);
 EpdFont ubuntuBold10Font(&ubuntu_bold_10);
 EpdFontFamily ubuntuFontFamily(&ubuntu10Font, &ubuntuBold10Font);
 
-// Power button timing
-// Time required to confirm boot from sleep
-constexpr unsigned long POWER_BUTTON_WAKEUP_MS = 500;
-// Time required to enter sleep mode
-constexpr unsigned long POWER_BUTTON_SLEEP_MS = 500;
 // 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) {
     currentActivity->onExit();
     delete currentActivity;
+    currentActivity = nullptr;
   }
 }
 
@@ -79,23 +79,28 @@ void enterNewActivity(Activity* activity) {
 
 // Verify long press on wake-up from deep sleep
 void verifyWakeupLongPress() {
-  // Give the user up to 1000ms to start holding the power button, and must hold for POWER_BUTTON_WAKEUP_MS
+  // 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;
 
-  Serial.printf("[%lu] [   ] Verifying power button press\n", millis());
   inputManager.update();
+  // Verify the user has actually pressed
   while (!inputManager.isPressed(InputManager::BTN_POWER) && millis() - start < 1000) {
-    delay(50);
+    delay(10);  // only wait 10ms each iteration to not delay too much in case of short configured duration.
     inputManager.update();
   }
 
+  t2 = millis();
   if (inputManager.isPressed(InputManager::BTN_POWER)) {
     do {
-      delay(50);
+      delay(10);
       inputManager.update();
-    } while (inputManager.isPressed(InputManager::BTN_POWER) && inputManager.getHeldTime() < POWER_BUTTON_WAKEUP_MS);
-    abort = inputManager.getHeldTime() < POWER_BUTTON_WAKEUP_MS;
+    } while (inputManager.isPressed(InputManager::BTN_POWER) && inputManager.getHeldTime() < calibratedPressDuration);
+    abort = inputManager.getHeldTime() < calibratedPressDuration;
   } else {
     abort = true;
   }
@@ -121,14 +126,12 @@ void enterDeepSleep() {
   exitActivity();
   enterNewActivity(new SleepActivity(renderer, inputManager));
 
-  Serial.printf("[%lu] [   ] Power button released after a long press. 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();
 }
@@ -140,6 +143,11 @@ void onGoToReader(const std::string& initialEpubPath) {
 }
 void onGoToReaderHome() { onGoToReader(std::string()); }
 
+void onGoToFileTransfer() {
+  exitActivity();
+  enterNewActivity(new CrossPointWebServerActivity(renderer, inputManager, onGoHome));
+}
+
 void onGoToSettings() {
   exitActivity();
   enterNewActivity(new SettingsActivity(renderer, inputManager, onGoHome));
@@ -147,44 +155,65 @@ void onGoToSettings() {
 
 void onGoHome() {
   exitActivity();
-  enterNewActivity(new HomeActivity(renderer, inputManager, onGoToReaderHome, onGoToSettings));
+  enterNewActivity(new HomeActivity(renderer, inputManager, 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() {
-  Serial.begin(115200);
+  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());
 
   inputManager.begin();
-  verifyWakeupLongPress();
-
   // Initialize pins
   pinMode(BAT_GPIO0, INPUT);
 
   // Initialize SPI with custom pins
   SPI.begin(EPD_SCLK, SD_SPI_MISO, EPD_MOSI, EPD_CS);
 
-  // Initialize display
-  einkDisplay.begin();
-  Serial.printf("[%lu] [   ] Display initialized\n", millis());
+  // SD Card Initialization
+  // 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;
+  }
 
-  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());
+  SETTINGS.loadFromFile();
+
+  // verify power button press duration after we've read settings.
+  verifyWakeupLongPress();
+
+  setupDisplayAndFonts();
 
   exitActivity();
   enterNewActivity(new BootActivity(renderer, inputManager));
 
-  // SD Card Initialization
-  SD.begin(SD_SPI_CS, SPI, SPI_FQ);
-
-  SETTINGS.loadFromFile();
   APP_STATE.loadFromFile();
   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
@@ -192,17 +221,18 @@ void setup() {
 }
 
 void loop() {
-  delay(10);
-
+  static unsigned long maxLoopDuration = 0;
+  const 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()) {
@@ -216,13 +246,34 @@ void loop() {
     return;
   }
 
-  if (inputManager.wasReleased(InputManager::BTN_POWER) && inputManager.getHeldTime() > POWER_BUTTON_SLEEP_MS) {
+  if (inputManager.isPressed(InputManager::BTN_POWER) &&
+      inputManager.getHeldTime() > SETTINGS.getPowerButtonDuration()) {
     enterDeepSleep();
     // This should never be hit as `enterDeepSleep` calls esp_deep_sleep_start
     return;
   }
 
+  const unsigned long activityStartTime = millis();
   if (currentActivity) {
     currentActivity->loop();
   }
+  const unsigned long activityDuration = millis() - activityStartTime;
+
+  const unsigned long loopDuration = millis() - loopStartTime;
+  if (loopDuration > maxLoopDuration) {
+    maxLoopDuration = loopDuration;
+    if (maxLoopDuration > 50) {
+      Serial.printf("[%lu] [LOOP] New max loop duration: %lu ms (activity: %lu ms)\n", millis(), maxLoopDuration,
+                    activityDuration);
+    }
+  }
+
+  // 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
+  if (currentActivity && currentActivity->skipLoopDelay()) {
+    yield();  // Give FreeRTOS a chance to run tasks, but return immediately
+  } else {
+    delay(10);  // Normal delay when no activity requires fast response
+  }
 }

src/network/CrossPointWebServer.cpp

@@ -0,0 +1,542 @@
+#include "CrossPointWebServer.h"
+
+#include <ArduinoJson.h>
+#include <FsHelpers.h>
+#include <SD.h>
+#include <WiFi.h>
+
+#include <algorithm>
+
+#include "html/FilesPageHtml.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"};
+constexpr size_t HIDDEN_ITEMS_COUNT = sizeof(HIDDEN_ITEMS) / sizeof(HIDDEN_ITEMS[0]);
+}  // namespace
+
+// File listing page template - now using generated headers:
+// - HomePageHtml (from html/HomePage.html)
+// - FilesPageHeaderHtml (from html/FilesPageHeader.html)
+// - FilesPageFooterHtml (from html/FilesPageFooter.html)
+CrossPointWebServer::CrossPointWebServer() {}
+
+CrossPointWebServer::~CrossPointWebServer() { stop(); }
+
+void CrossPointWebServer::begin() {
+  if (running) {
+    Serial.printf("[%lu] [WEB] Web server already running\n", millis());
+    return;
+  }
+
+  // Check if we have a valid network connection (either STA connected or AP mode)
+  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.reset(new WebServer(port));
+  Serial.printf("[%lu] [WEB] [MEM] Free heap after WebServer allocation: %d bytes\n", millis(), ESP.getFreeHeap());
+
+  if (!server) {
+    Serial.printf("[%lu] [WEB] Failed to create WebServer!\n", millis());
+    return;
+  }
+
+  // Setup routes
+  Serial.printf("[%lu] [WEB] Setting up routes...\n", millis());
+  server->on("/", HTTP_GET, [this] { handleRoot(); });
+  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(); });
+
+  // Create folder endpoint
+  server->on("/mkdir", HTTP_POST, [this] { handleCreateFolder(); });
+
+  // Delete file/folder endpoint
+  server->on("/delete", HTTP_POST, [this] { handleDelete(); });
+
+  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);
+  // 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.get());
+    return;
+  }
+
+  Serial.printf("[%lu] [WEB] STOP INITIATED - setting running=false first\n", millis());
+  running = false;  // Set this FIRST to prevent handleClient from using server
+
+  Serial.printf("[%lu] [WEB] [MEM] Free heap before stop: %d bytes\n", millis(), ESP.getFreeHeap());
+
+  // Add delay to allow any in-flight handleClient() calls to complete
+  delay(100);
+  Serial.printf("[%lu] [WEB] Waited 100ms for handleClient to finish\n", millis());
+
+  server->stop();
+  Serial.printf("[%lu] [WEB] [MEM] Free heap after server->stop(): %d bytes\n", millis(), ESP.getFreeHeap());
+
+  // Add another delay before deletion to ensure server->stop() completes
+  delay(50);
+  Serial.printf("[%lu] [WEB] Waited 50ms before deleting server\n", millis());
+
+  server.reset();
+  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());
+
+  // Note: Static upload variables (uploadFileName, uploadPath, uploadError) are declared
+  // later in the file and will be cleared when they go out of scope or on next upload
+  Serial.printf("[%lu] [WEB] [MEM] Free heap final: %d bytes\n", millis(), ESP.getFreeHeap());
+}
+
+void CrossPointWebServer::handleClient() const {
+  static unsigned long lastDebugPrint = 0;
+
+  // Check running flag FIRST before accessing server
+  if (!running) {
+    return;
+  }
+
+  // Double-check server pointer is valid
+  if (!server) {
+    Serial.printf("[%lu] [WEB] WARNING: handleClient called with null server!\n", millis());
+    return;
+  }
+
+  // Print debug every 10 seconds to confirm handleClient is being called
+  if (millis() - lastDebugPrint > 10000) {
+    Serial.printf("[%lu] [WEB] handleClient active, server running on port %d\n", millis(), port);
+    lastDebugPrint = millis();
+  }
+
+  server->handleClient();
+}
+
+void CrossPointWebServer::handleRoot() const {
+  server->send(200, "text/html", HomePageHtml);
+  Serial.printf("[%lu] [WEB] Served root page\n", millis());
+}
+
+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() 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\":\"" + ipAddr + "\",";
+  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 += "}";
+
+  server->send(200, "application/json", json);
+}
+
+void CrossPointWebServer::scanFiles(const char* path, const std::function<void(FileInfo)>& callback) const {
+  File root = SD.open(path);
+  if (!root) {
+    Serial.printf("[%lu] [WEB] Failed to open directory: %s\n", millis(), path);
+    return;
+  }
+
+  if (!root.isDirectory()) {
+    Serial.printf("[%lu] [WEB] Not a directory: %s\n", millis(), path);
+    root.close();
+    return;
+  }
+
+  Serial.printf("[%lu] [WEB] Scanning files in: %s\n", millis(), path);
+
+  File file = root.openNextFile();
+  while (file) {
+    auto fileName = String(file.name());
+
+    // Skip hidden items (starting with ".")
+    bool shouldHide = fileName.startsWith(".");
+
+    // Check against explicitly hidden items list
+    if (!shouldHide) {
+      for (size_t i = 0; i < HIDDEN_ITEMS_COUNT; i++) {
+        if (fileName.equals(HIDDEN_ITEMS[i])) {
+          shouldHide = true;
+          break;
+        }
+      }
+    }
+
+    if (!shouldHide) {
+      FileInfo info;
+      info.name = fileName;
+      info.isDirectory = file.isDirectory();
+
+      if (info.isDirectory) {
+        info.size = 0;
+        info.isEpub = false;
+      } else {
+        info.size = file.size();
+        info.isEpub = isEpubFile(info.name);
+      }
+
+      callback(info);
+    }
+
+    file.close();
+    file = root.openNextFile();
+  }
+  root.close();
+}
+
+bool CrossPointWebServer::isEpubFile(const String& filename) const {
+  String lower = filename;
+  lower.toLowerCase();
+  return lower.endsWith(".epub");
+}
+
+void CrossPointWebServer::handleFileList() const { server->send(200, "text/html", FilesPageHtml); }
+
+void CrossPointWebServer::handleFileListData() const {
+  // Get current path from query string (default to root)
+  String currentPath = "/";
+  if (server->hasArg("path")) {
+    currentPath = server->arg("path");
+    // Ensure path starts with /
+    if (!currentPath.startsWith("/")) {
+      currentPath = "/" + currentPath;
+    }
+    // Remove trailing slash unless it's root
+    if (currentPath.length() > 1 && currentPath.endsWith("/")) {
+      currentPath = currentPath.substring(0, currentPath.length() - 1);
+    }
+  }
+
+  server->setContentLength(CONTENT_LENGTH_UNKNOWN);
+  server->send(200, "application/json", "");
+  server->sendContent("[");
+  char output[512];
+  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;
+    }
+
+    if (seenFirst) {
+      server->sendContent(",");
+    } else {
+      seenFirst = true;
+    }
+    server->sendContent(output);
+  });
+  server->sendContent("]");
+  // End of streamed response, empty chunk to signal client
+  server->sendContent("");
+  Serial.printf("[%lu] [WEB] Served file listing page for path: %s\n", millis(), currentPath.c_str());
+}
+
+// Static variables for upload handling
+static File uploadFile;
+static String uploadFileName;
+static String uploadPath = "/";
+static size_t uploadSize = 0;
+static bool uploadSuccess = false;
+static String uploadError = "";
+
+void CrossPointWebServer::handleUpload() const {
+  static unsigned long lastWriteTime = 0;
+  static unsigned long uploadStartTime = 0;
+  static size_t lastLoggedSize = 0;
+
+  // Safety check: ensure server is still valid
+  if (!running || !server) {
+    Serial.printf("[%lu] [WEB] [UPLOAD] ERROR: handleUpload called but server not running!\n", millis());
+    return;
+  }
+
+  const HTTPUpload& upload = server->upload();
+
+  if (upload.status == UPLOAD_FILE_START) {
+    uploadFileName = upload.filename;
+    uploadSize = 0;
+    uploadSuccess = false;
+    uploadError = "";
+    uploadStartTime = millis();
+    lastWriteTime = millis();
+    lastLoggedSize = 0;
+
+    // Get upload path from query parameter (defaults to root if not specified)
+    // Note: We use query parameter instead of form data because multipart form
+    // fields aren't available until after file upload completes
+    if (server->hasArg("path")) {
+      uploadPath = server->arg("path");
+      // Ensure path starts with /
+      if (!uploadPath.startsWith("/")) {
+        uploadPath = "/" + uploadPath;
+      }
+      // Remove trailing slash unless it's root
+      if (uploadPath.length() > 1 && uploadPath.endsWith("/")) {
+        uploadPath = uploadPath.substring(0, uploadPath.length() - 1);
+      }
+    } else {
+      uploadPath = "/";
+    }
+
+    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());
+
+    // Create file path
+    String filePath = uploadPath;
+    if (!filePath.endsWith("/")) filePath += "/";
+    filePath += uploadFileName;
+
+    // Check if file already exists
+    if (SD.exists(filePath.c_str())) {
+      Serial.printf("[%lu] [WEB] [UPLOAD] Overwriting existing file: %s\n", millis(), filePath.c_str());
+      SD.remove(filePath.c_str());
+    }
+
+    // Open file for writing
+    if (!FsHelpers::openFileForWrite("WEB", filePath, 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;
+    }
+
+    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()) {
+      const unsigned long writeStartTime = millis();
+      const size_t written = uploadFile.write(upload.buf, upload.currentSize);
+      const unsigned long writeEndTime = millis();
+      const unsigned long writeDuration = writeEndTime - writeStartTime;
+
+      if (written != upload.currentSize) {
+        uploadError = "Failed to write to SD card - disk may be full";
+        uploadFile.close();
+        Serial.printf("[%lu] [WEB] [UPLOAD] WRITE ERROR - expected %d, wrote %d\n", millis(), upload.currentSize,
+                      written);
+      } else {
+        uploadSize += written;
+
+        // Log progress every 50KB or if write took >100ms
+        if (uploadSize - lastLoggedSize >= 51200 || writeDuration > 100) {
+          const unsigned long timeSinceStart = millis() - uploadStartTime;
+          const unsigned long timeSinceLastWrite = millis() - lastWriteTime;
+          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 "
+              "ms\n",
+              millis(), uploadSize, uploadSize / 1024.0, kbps, writeDuration, timeSinceLastWrite);
+          lastLoggedSize = uploadSize;
+        }
+        lastWriteTime = millis();
+      }
+    }
+  } else if (upload.status == UPLOAD_FILE_END) {
+    if (uploadFile) {
+      uploadFile.close();
+
+      if (uploadError.isEmpty()) {
+        uploadSuccess = true;
+        Serial.printf("[%lu] [WEB] Upload complete: %s (%d bytes)\n", millis(), uploadFileName.c_str(), uploadSize);
+      }
+    }
+  } else if (upload.status == UPLOAD_FILE_ABORTED) {
+    if (uploadFile) {
+      uploadFile.close();
+      // Try to delete the incomplete file
+      String filePath = uploadPath;
+      if (!filePath.endsWith("/")) filePath += "/";
+      filePath += uploadFileName;
+      SD.remove(filePath.c_str());
+    }
+    uploadError = "Upload aborted";
+    Serial.printf("[%lu] [WEB] Upload aborted\n", millis());
+  }
+}
+
+void CrossPointWebServer::handleUploadPost() const {
+  if (uploadSuccess) {
+    server->send(200, "text/plain", "File uploaded successfully: " + uploadFileName);
+  } else {
+    const String error = uploadError.isEmpty() ? "Unknown error during upload" : uploadError;
+    server->send(400, "text/plain", error);
+  }
+}
+
+void CrossPointWebServer::handleCreateFolder() const {
+  // Get folder name from form data
+  if (!server->hasArg("name")) {
+    server->send(400, "text/plain", "Missing folder name");
+    return;
+  }
+
+  const String folderName = server->arg("name");
+
+  // Validate folder name
+  if (folderName.isEmpty()) {
+    server->send(400, "text/plain", "Folder name cannot be empty");
+    return;
+  }
+
+  // Get parent path
+  String parentPath = "/";
+  if (server->hasArg("path")) {
+    parentPath = server->arg("path");
+    if (!parentPath.startsWith("/")) {
+      parentPath = "/" + parentPath;
+    }
+    if (parentPath.length() > 1 && parentPath.endsWith("/")) {
+      parentPath = parentPath.substring(0, parentPath.length() - 1);
+    }
+  }
+
+  // Build full folder path
+  String folderPath = parentPath;
+  if (!folderPath.endsWith("/")) folderPath += "/";
+  folderPath += folderName;
+
+  Serial.printf("[%lu] [WEB] Creating folder: %s\n", millis(), folderPath.c_str());
+
+  // Check if already exists
+  if (SD.exists(folderPath.c_str())) {
+    server->send(400, "text/plain", "Folder already exists");
+    return;
+  }
+
+  // Create the folder
+  if (SD.mkdir(folderPath.c_str())) {
+    Serial.printf("[%lu] [WEB] Folder created successfully: %s\n", millis(), folderPath.c_str());
+    server->send(200, "text/plain", "Folder created: " + folderName);
+  } else {
+    Serial.printf("[%lu] [WEB] Failed to create folder: %s\n", millis(), folderPath.c_str());
+    server->send(500, "text/plain", "Failed to create folder");
+  }
+}
+
+void CrossPointWebServer::handleDelete() const {
+  // Get path from form data
+  if (!server->hasArg("path")) {
+    server->send(400, "text/plain", "Missing path");
+    return;
+  }
+
+  String itemPath = server->arg("path");
+  const String itemType = server->hasArg("type") ? server->arg("type") : "file";
+
+  // Validate path
+  if (itemPath.isEmpty() || itemPath == "/") {
+    server->send(400, "text/plain", "Cannot delete root directory");
+    return;
+  }
+
+  // Ensure path starts with /
+  if (!itemPath.startsWith("/")) {
+    itemPath = "/" + itemPath;
+  }
+
+  // Security check: prevent deletion of protected items
+  const String itemName = itemPath.substring(itemPath.lastIndexOf('/') + 1);
+
+  // Check if item starts with a dot (hidden/system file)
+  if (itemName.startsWith(".")) {
+    Serial.printf("[%lu] [WEB] Delete rejected - hidden/system item: %s\n", millis(), itemPath.c_str());
+    server->send(403, "text/plain", "Cannot delete system files");
+    return;
+  }
+
+  // Check against explicitly protected items
+  for (size_t i = 0; i < HIDDEN_ITEMS_COUNT; i++) {
+    if (itemName.equals(HIDDEN_ITEMS[i])) {
+      Serial.printf("[%lu] [WEB] Delete rejected - protected item: %s\n", millis(), itemPath.c_str());
+      server->send(403, "text/plain", "Cannot delete protected items");
+      return;
+    }
+  }
+
+  // Check if item exists
+  if (!SD.exists(itemPath.c_str())) {
+    Serial.printf("[%lu] [WEB] Delete failed - item not found: %s\n", millis(), itemPath.c_str());
+    server->send(404, "text/plain", "Item not found");
+    return;
+  }
+
+  Serial.printf("[%lu] [WEB] Attempting to delete %s: %s\n", millis(), itemType.c_str(), itemPath.c_str());
+
+  bool success = false;
+
+  if (itemType == "folder") {
+    // For folders, try to remove (will fail if not empty)
+    File dir = SD.open(itemPath.c_str());
+    if (dir && dir.isDirectory()) {
+      // Check if folder is empty
+      File entry = dir.openNextFile();
+      if (entry) {
+        // Folder is not empty
+        entry.close();
+        dir.close();
+        Serial.printf("[%lu] [WEB] Delete failed - folder not empty: %s\n", millis(), itemPath.c_str());
+        server->send(400, "text/plain", "Folder is not empty. Delete contents first.");
+        return;
+      }
+      dir.close();
+    }
+    success = SD.rmdir(itemPath.c_str());
+  } else {
+    // For files, use remove
+    success = SD.remove(itemPath.c_str());
+  }
+
+  if (success) {
+    Serial.printf("[%lu] [WEB] Successfully deleted: %s\n", millis(), itemPath.c_str());
+    server->send(200, "text/plain", "Deleted successfully");
+  } else {
+    Serial.printf("[%lu] [WEB] Failed to delete: %s\n", millis(), itemPath.c_str());
+    server->send(500, "text/plain", "Failed to delete item");
+  }
+}

src/network/CrossPointWebServer.h

@@ -0,0 +1,56 @@
+#pragma once
+
+#include <WebServer.h>
+
+#include <vector>
+
+// Structure to hold file information
+struct FileInfo {
+  String name;
+  size_t size;
+  bool isEpub;
+  bool isDirectory;
+};
+
+class CrossPointWebServer {
+ public:
+  CrossPointWebServer();
+  ~CrossPointWebServer();
+
+  // Start the web server (call after WiFi is connected)
+  void begin();
+
+  // Stop the web server
+  void stop();
+
+  // Call this periodically to handle client requests
+  void handleClient() const;
+
+  // Check if server is running
+  bool isRunning() const { return running; }
+
+  // Get the port number
+  uint16_t getPort() const { return port; }
+
+ private:
+  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
+  void scanFiles(const char* path, const std::function<void(FileInfo)>& callback) const;
+  String formatFileSize(size_t bytes) const;
+  bool isEpubFile(const String& filename) const;
+
+  // Request handlers
+  void handleRoot() const;
+  void handleNotFound() const;
+  void handleStatus() const;
+  void handleFileList() const;
+  void handleFileListData() const;
+  void handleUpload() const;
+  void handleUploadPost() const;
+  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

@@ -0,0 +1,129 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>CrossPoint Reader</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;
+        border-bottom: 2px solid #3498db;
+        padding-bottom: 10px;
+      }
+      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);
+      }
+      .info-row {
+        display: flex;
+        justify-content: space-between;
+        padding: 8px 0;
+        border-bottom: 1px solid #eee;
+      }
+      .info-row:last-child {
+        border-bottom: none;
+      }
+      .label {
+        font-weight: 600;
+        color: #7f8c8d;
+      }
+      .value {
+        color: #2c3e50;
+      }
+      .status {
+        display: inline-block;
+        padding: 4px 12px;
+        border-radius: 12px;
+        background-color: #27ae60;
+        color: white;
+        font-size: 0.9em;
+      }
+      .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;
+      }
+    </style>
+  </head>
+  <body>
+    <h1>📚 CrossPoint Reader</h1>
+
+    <div class="nav-links">
+      <a href="/">Home</a>
+      <a href="/files">File Manager</a>
+    </div>
+
+    <div class="card">
+      <h2>Device Status</h2>
+      <div class="info-row">
+        <span class="label">Version</span>
+        <span class="value" id="version"></span>
+      </div>
+      <div class="info-row">
+        <span class="label">WiFi Status</span>
+        <span class="status">Connected</span>
+      </div>
+      <div class="info-row">
+        <span class="label">IP Address</span>
+        <span class="value" id="ip-address"></span>
+      </div>
+      <div class="info-row">
+        <span class="label">Free Memory</span>
+        <span class="value" id="free-heap"></span>
+      </div>
+    </div>
+
+    <div class="card">
+      <p style="text-align: center; color: #95a5a6; margin: 0">
+        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>