feat: Sleep screen letterbox fill and image upscaling

Add configurable letterbox fill for sleep screen cover images that don't
match the display aspect ratio. Four fill modes are available: Solid
(single dominant edge shade), Blended (per-pixel edge colors), Gradient
(edge colors interpolated toward white/black), and None.

Enable upscaling of cover images smaller than the display in Fit mode by
modifying drawBitmap/drawBitmap1Bit to support both up and downscaling
via a unified block-fill approach.

Edge sampling data is cached to .crosspoint alongside the cover BMP to
avoid redundant bitmap scanning on subsequent sleeps. Cache is validated
against screen dimensions and auto-regenerated when stale.

New settings: Letterbox Fill (None/Solid/Blended/Gradient) and Gradient
Direction (To White/To Black).

Co-authored-by: Cursor <cursoragent@cursor.com>

.gitignore

@@ -9,3 +9,8 @@ build
 **/__pycache__/
 /compile_commands.json
 /.cache
+
+# mod
+mod/*
+.cursor/*
+chat-summaries/*

lib/Epub/Epub.cpp

@@ -1,9 +1,9 @@
 #include "Epub.h"
 
 #include <FsHelpers.h>
+#include <HalStorage.h>
 #include <HardwareSerial.h>
 #include <JpegToBmpConverter.h>
-#include <SDCardManager.h>
 #include <ZipFile.h>
 
 #include "Epub/parsers/ContainerParser.h"
@@ -105,12 +105,12 @@ bool Epub::parseTocNcxFile() const {
 
   const auto tmpNcxPath = getCachePath() + "/toc.ncx";
   FsFile tempNcxFile;
-  if (!SdMan.openFileForWrite("EBP", tmpNcxPath, tempNcxFile)) {
+  if (!Storage.openFileForWrite("EBP", tmpNcxPath, tempNcxFile)) {
     return false;
   }
   readItemContentsToStream(tocNcxItem, tempNcxFile, 1024);
   tempNcxFile.close();
-  if (!SdMan.openFileForRead("EBP", tmpNcxPath, tempNcxFile)) {
+  if (!Storage.openFileForRead("EBP", tmpNcxPath, tempNcxFile)) {
     return false;
   }
   const auto ncxSize = tempNcxFile.size();
@@ -145,7 +145,7 @@ bool Epub::parseTocNcxFile() const {
 
   free(ncxBuffer);
   tempNcxFile.close();
-  SdMan.remove(tmpNcxPath.c_str());
+  Storage.remove(tmpNcxPath.c_str());
 
   Serial.printf("[%lu] [EBP] Parsed TOC items\n", millis());
   return true;
@@ -162,12 +162,12 @@ bool Epub::parseTocNavFile() const {
 
   const auto tmpNavPath = getCachePath() + "/toc.nav";
   FsFile tempNavFile;
-  if (!SdMan.openFileForWrite("EBP", tmpNavPath, tempNavFile)) {
+  if (!Storage.openFileForWrite("EBP", tmpNavPath, tempNavFile)) {
     return false;
   }
   readItemContentsToStream(tocNavItem, tempNavFile, 1024);
   tempNavFile.close();
-  if (!SdMan.openFileForRead("EBP", tmpNavPath, tempNavFile)) {
+  if (!Storage.openFileForRead("EBP", tmpNavPath, tempNavFile)) {
     return false;
   }
   const auto navSize = tempNavFile.size();
@@ -202,7 +202,7 @@ bool Epub::parseTocNavFile() const {
 
   free(navBuffer);
   tempNavFile.close();
-  SdMan.remove(tmpNavPath.c_str());
+  Storage.remove(tmpNavPath.c_str());
 
   Serial.printf("[%lu] [EBP] Parsed TOC nav items\n", millis());
   return true;
@@ -212,7 +212,7 @@ std::string Epub::getCssRulesCache() const { return cachePath + "/css_rules.cach
 
 bool Epub::loadCssRulesFromCache() const {
   FsFile cssCacheFile;
-  if (SdMan.openFileForRead("EBP", getCssRulesCache(), cssCacheFile)) {
+  if (Storage.openFileForRead("EBP", getCssRulesCache(), cssCacheFile)) {
     if (cssParser->loadFromCache(cssCacheFile)) {
       cssCacheFile.close();
       Serial.printf("[%lu] [EBP] Loaded CSS rules from cache\n", millis());
@@ -238,32 +238,32 @@ void Epub::parseCssFiles() const {
       // Extract CSS file to temp location
       const auto tmpCssPath = getCachePath() + "/.tmp.css";
       FsFile tempCssFile;
-      if (!SdMan.openFileForWrite("EBP", tmpCssPath, tempCssFile)) {
+      if (!Storage.openFileForWrite("EBP", tmpCssPath, tempCssFile)) {
         Serial.printf("[%lu] [EBP] Could not create temp CSS file\n", millis());
         continue;
       }
       if (!readItemContentsToStream(cssPath, tempCssFile, 1024)) {
         Serial.printf("[%lu] [EBP] Could not read CSS file: %s\n", millis(), cssPath.c_str());
         tempCssFile.close();
-        SdMan.remove(tmpCssPath.c_str());
+        Storage.remove(tmpCssPath.c_str());
         continue;
       }
       tempCssFile.close();
 
       // Parse the CSS file
-      if (!SdMan.openFileForRead("EBP", tmpCssPath, tempCssFile)) {
+      if (!Storage.openFileForRead("EBP", tmpCssPath, tempCssFile)) {
         Serial.printf("[%lu] [EBP] Could not open temp CSS file for reading\n", millis());
-        SdMan.remove(tmpCssPath.c_str());
+        Storage.remove(tmpCssPath.c_str());
         continue;
       }
       cssParser->loadFromStream(tempCssFile);
       tempCssFile.close();
-      SdMan.remove(tmpCssPath.c_str());
+      Storage.remove(tmpCssPath.c_str());
     }
 
     // Save to cache for next time
     FsFile cssCacheFile;
-    if (SdMan.openFileForWrite("EBP", getCssRulesCache(), cssCacheFile)) {
+    if (Storage.openFileForWrite("EBP", getCssRulesCache(), cssCacheFile)) {
       cssParser->saveToCache(cssCacheFile);
       cssCacheFile.close();
     }
@@ -399,12 +399,12 @@ bool Epub::load(const bool buildIfMissing, const bool skipLoadingCss) {
 }
 
 bool Epub::clearCache() const {
-  if (!SdMan.exists(cachePath.c_str())) {
+  if (!Storage.exists(cachePath.c_str())) {
     Serial.printf("[%lu] [EPB] Cache does not exist, no action needed\n", millis());
     return true;
   }
 
-  if (!SdMan.removeDir(cachePath.c_str())) {
+  if (!Storage.removeDir(cachePath.c_str())) {
     Serial.printf("[%lu] [EPB] Failed to clear cache\n", millis());
     return false;
   }
@@ -414,11 +414,11 @@ bool Epub::clearCache() const {
 }
 
 void Epub::setupCacheDir() const {
-  if (SdMan.exists(cachePath.c_str())) {
+  if (Storage.exists(cachePath.c_str())) {
     return;
   }
 
-  SdMan.mkdir(cachePath.c_str());
+  Storage.mkdir(cachePath.c_str());
 }
 
 const std::string& Epub::getCachePath() const { return cachePath; }
@@ -459,7 +459,7 @@ std::string Epub::getCoverBmpPath(bool cropped) const {
 
 bool Epub::generateCoverBmp(bool cropped) const {
   // Already generated, return true
-  if (SdMan.exists(getCoverBmpPath(cropped).c_str())) {
+  if (Storage.exists(getCoverBmpPath(cropped).c_str())) {
     return true;
   }
 
@@ -480,29 +480,29 @@ bool Epub::generateCoverBmp(bool cropped) const {
     const auto coverJpgTempPath = getCachePath() + "/.cover.jpg";
 
     FsFile coverJpg;
-    if (!SdMan.openFileForWrite("EBP", coverJpgTempPath, coverJpg)) {
+    if (!Storage.openFileForWrite("EBP", coverJpgTempPath, coverJpg)) {
       return false;
     }
     readItemContentsToStream(coverImageHref, coverJpg, 1024);
     coverJpg.close();
 
-    if (!SdMan.openFileForRead("EBP", coverJpgTempPath, coverJpg)) {
+    if (!Storage.openFileForRead("EBP", coverJpgTempPath, coverJpg)) {
       return false;
     }
 
     FsFile coverBmp;
-    if (!SdMan.openFileForWrite("EBP", getCoverBmpPath(cropped), coverBmp)) {
+    if (!Storage.openFileForWrite("EBP", getCoverBmpPath(cropped), coverBmp)) {
       coverJpg.close();
       return false;
     }
     const bool success = JpegToBmpConverter::jpegFileToBmpStream(coverJpg, coverBmp, cropped);
     coverJpg.close();
     coverBmp.close();
-    SdMan.remove(coverJpgTempPath.c_str());
+    Storage.remove(coverJpgTempPath.c_str());
 
     if (!success) {
       Serial.printf("[%lu] [EBP] Failed to generate BMP from JPG cover image\n", millis());
-      SdMan.remove(getCoverBmpPath(cropped).c_str());
+      Storage.remove(getCoverBmpPath(cropped).c_str());
     }
     Serial.printf("[%lu] [EBP] Generated BMP from JPG cover image, success: %s\n", millis(), success ? "yes" : "no");
     return success;
@@ -518,7 +518,7 @@ std::string Epub::getThumbBmpPath(int height) const { return cachePath + "/thumb
 
 bool Epub::generateThumbBmp(int height) const {
   // Already generated, return true
-  if (SdMan.exists(getThumbBmpPath(height).c_str())) {
+  if (Storage.exists(getThumbBmpPath(height).c_str())) {
     return true;
   }
 
@@ -536,18 +536,18 @@ bool Epub::generateThumbBmp(int height) const {
     const auto coverJpgTempPath = getCachePath() + "/.cover.jpg";
 
     FsFile coverJpg;
-    if (!SdMan.openFileForWrite("EBP", coverJpgTempPath, coverJpg)) {
+    if (!Storage.openFileForWrite("EBP", coverJpgTempPath, coverJpg)) {
       return false;
     }
     readItemContentsToStream(coverImageHref, coverJpg, 1024);
     coverJpg.close();
 
-    if (!SdMan.openFileForRead("EBP", coverJpgTempPath, coverJpg)) {
+    if (!Storage.openFileForRead("EBP", coverJpgTempPath, coverJpg)) {
       return false;
     }
 
     FsFile thumbBmp;
-    if (!SdMan.openFileForWrite("EBP", getThumbBmpPath(height), thumbBmp)) {
+    if (!Storage.openFileForWrite("EBP", getThumbBmpPath(height), thumbBmp)) {
       coverJpg.close();
       return false;
     }
@@ -559,11 +559,11 @@ bool Epub::generateThumbBmp(int height) const {
                                                                              THUMB_TARGET_HEIGHT);
     coverJpg.close();
     thumbBmp.close();
-    SdMan.remove(coverJpgTempPath.c_str());
+    Storage.remove(coverJpgTempPath.c_str());
 
     if (!success) {
       Serial.printf("[%lu] [EBP] Failed to generate thumb BMP from JPG cover image\n", millis());
-      SdMan.remove(getThumbBmpPath(height).c_str());
+      Storage.remove(getThumbBmpPath(height).c_str());
     }
     Serial.printf("[%lu] [EBP] Generated thumb BMP from JPG cover image, success: %s\n", millis(),
                   success ? "yes" : "no");
@@ -574,7 +574,7 @@ bool Epub::generateThumbBmp(int height) const {
 
   // Write an empty bmp file to avoid generation attempts in the future
   FsFile thumbBmp;
-  SdMan.openFileForWrite("EBP", getThumbBmpPath(height), thumbBmp);
+  Storage.openFileForWrite("EBP", getThumbBmpPath(height), thumbBmp);
   thumbBmp.close();
   return false;
 }

lib/Epub/Epub/BookMetadataCache.cpp

@@ -29,7 +29,7 @@ bool BookMetadataCache::beginContentOpfPass() {
   Serial.printf("[%lu] [BMC] Beginning content opf pass\n", millis());
 
   // Open spine file for writing
-  return SdMan.openFileForWrite("BMC", cachePath + tmpSpineBinFile, spineFile);
+  return Storage.openFileForWrite("BMC", cachePath + tmpSpineBinFile, spineFile);
 }
 
 bool BookMetadataCache::endContentOpfPass() {
@@ -40,10 +40,10 @@ bool BookMetadataCache::endContentOpfPass() {
 bool BookMetadataCache::beginTocPass() {
   Serial.printf("[%lu] [BMC] Beginning toc pass\n", millis());
 
-  if (!SdMan.openFileForRead("BMC", cachePath + tmpSpineBinFile, spineFile)) {
+  if (!Storage.openFileForRead("BMC", cachePath + tmpSpineBinFile, spineFile)) {
     return false;
   }
-  if (!SdMan.openFileForWrite("BMC", cachePath + tmpTocBinFile, tocFile)) {
+  if (!Storage.openFileForWrite("BMC", cachePath + tmpTocBinFile, tocFile)) {
     spineFile.close();
     return false;
   }
@@ -98,16 +98,16 @@ bool BookMetadataCache::endWrite() {
 
 bool BookMetadataCache::buildBookBin(const std::string& epubPath, const BookMetadata& metadata) {
   // Open all three files, writing to meta, reading from spine and toc
-  if (!SdMan.openFileForWrite("BMC", cachePath + bookBinFile, bookFile)) {
+  if (!Storage.openFileForWrite("BMC", cachePath + bookBinFile, bookFile)) {
     return false;
   }
 
-  if (!SdMan.openFileForRead("BMC", cachePath + tmpSpineBinFile, spineFile)) {
+  if (!Storage.openFileForRead("BMC", cachePath + tmpSpineBinFile, spineFile)) {
     bookFile.close();
     return false;
   }
 
-  if (!SdMan.openFileForRead("BMC", cachePath + tmpTocBinFile, tocFile)) {
+  if (!Storage.openFileForRead("BMC", cachePath + tmpTocBinFile, tocFile)) {
     bookFile.close();
     spineFile.close();
     return false;
@@ -275,11 +275,11 @@ bool BookMetadataCache::buildBookBin(const std::string& epubPath, const BookMeta
 }
 
 bool BookMetadataCache::cleanupTmpFiles() const {
-  if (SdMan.exists((cachePath + tmpSpineBinFile).c_str())) {
+  if (Storage.exists((cachePath + tmpSpineBinFile).c_str())) {
-    SdMan.remove((cachePath + tmpSpineBinFile).c_str());
+    Storage.remove((cachePath + tmpSpineBinFile).c_str());
   }
-  if (SdMan.exists((cachePath + tmpTocBinFile).c_str())) {
+  if (Storage.exists((cachePath + tmpTocBinFile).c_str())) {
-    SdMan.remove((cachePath + tmpTocBinFile).c_str());
+    Storage.remove((cachePath + tmpTocBinFile).c_str());
   }
   return true;
 }
@@ -364,7 +364,7 @@ void BookMetadataCache::createTocEntry(const std::string& title, const std::stri
 /* ============= READING / LOADING FUNCTIONS ================ */
 
 bool BookMetadataCache::load() {
-  if (!SdMan.openFileForRead("BMC", cachePath + bookBinFile, bookFile)) {
+  if (!Storage.openFileForRead("BMC", cachePath + bookBinFile, bookFile)) {
     return false;
   }
 

lib/Epub/Epub/BookMetadataCache.h

@@ -1,6 +1,6 @@
 #pragma once
 
-#include <SDCardManager.h>
+#include <HalStorage.h>
 
 #include <algorithm>
 #include <string>

lib/Epub/Epub/Page.h

@@ -1,5 +1,5 @@
 #pragma once
-#include <SdFat.h>
+#include <HalStorage.h>
 
 #include <utility>
 #include <vector>

lib/Epub/Epub/Section.cpp

@@ -1,6 +1,6 @@
 #include "Section.h"
 
-#include <SDCardManager.h>
+#include <HalStorage.h>
 #include <Serialization.h>
 
 #include "Page.h"
@@ -60,7 +60,7 @@ void Section::writeSectionFileHeader(const int fontId, const float lineCompressi
 bool Section::loadSectionFile(const int fontId, const float lineCompression, const bool extraParagraphSpacing,
                               const uint8_t paragraphAlignment, const uint16_t viewportWidth,
                               const uint16_t viewportHeight, const bool hyphenationEnabled, const bool embeddedStyle) {
-  if (!SdMan.openFileForRead("SCT", filePath, file)) {
+  if (!Storage.openFileForRead("SCT", filePath, file)) {
     return false;
   }
 
@@ -110,12 +110,12 @@ bool Section::loadSectionFile(const int fontId, const float lineCompression, con
 
 // Your updated class method (assuming you are using the 'SD' object, which is a wrapper for a specific filesystem)
 bool Section::clearCache() const {
-  if (!SdMan.exists(filePath.c_str())) {
+  if (!Storage.exists(filePath.c_str())) {
     Serial.printf("[%lu] [SCT] Cache does not exist, no action needed\n", millis());
     return true;
   }
 
-  if (!SdMan.remove(filePath.c_str())) {
+  if (!Storage.remove(filePath.c_str())) {
     Serial.printf("[%lu] [SCT] Failed to clear cache\n", millis());
     return false;
   }
@@ -134,7 +134,7 @@ bool Section::createSectionFile(const int fontId, const float lineCompression, c
   // Create cache directory if it doesn't exist
   {
     const auto sectionsDir = epub->getCachePath() + "/sections";
-    SdMan.mkdir(sectionsDir.c_str());
+    Storage.mkdir(sectionsDir.c_str());
   }
 
   // Retry logic for SD card timing issues
@@ -147,12 +147,12 @@ bool Section::createSectionFile(const int fontId, const float lineCompression, c
     }
 
     // Remove any incomplete file from previous attempt before retrying
-    if (SdMan.exists(tmpHtmlPath.c_str())) {
+    if (Storage.exists(tmpHtmlPath.c_str())) {
-      SdMan.remove(tmpHtmlPath.c_str());
+      Storage.remove(tmpHtmlPath.c_str());
     }
 
     FsFile tmpHtml;
-    if (!SdMan.openFileForWrite("SCT", tmpHtmlPath, tmpHtml)) {
+    if (!Storage.openFileForWrite("SCT", tmpHtmlPath, tmpHtml)) {
       continue;
     }
     success = epub->readItemContentsToStream(localPath, tmpHtml, 1024);
@@ -160,8 +160,8 @@ bool Section::createSectionFile(const int fontId, const float lineCompression, c
     tmpHtml.close();
 
     // If streaming failed, remove the incomplete file immediately
-    if (!success && SdMan.exists(tmpHtmlPath.c_str())) {
+    if (!success && Storage.exists(tmpHtmlPath.c_str())) {
-      SdMan.remove(tmpHtmlPath.c_str());
+      Storage.remove(tmpHtmlPath.c_str());
       Serial.printf("[%lu] [SCT] Removed incomplete temp file after failed attempt\n", millis());
     }
   }
@@ -173,7 +173,7 @@ bool Section::createSectionFile(const int fontId, const float lineCompression, c
 
   Serial.printf("[%lu] [SCT] Streamed temp HTML to %s (%d bytes)\n", millis(), tmpHtmlPath.c_str(), fileSize);
 
-  if (!SdMan.openFileForWrite("SCT", filePath, file)) {
+  if (!Storage.openFileForWrite("SCT", filePath, file)) {
     return false;
   }
   writeSectionFileHeader(fontId, lineCompression, extraParagraphSpacing, paragraphAlignment, viewportWidth,
@@ -188,11 +188,11 @@ bool Section::createSectionFile(const int fontId, const float lineCompression, c
   Hyphenator::setPreferredLanguage(epub->getLanguage());
   success = visitor.parseAndBuildPages();
 
-  SdMan.remove(tmpHtmlPath.c_str());
+  Storage.remove(tmpHtmlPath.c_str());
   if (!success) {
     Serial.printf("[%lu] [SCT] Failed to parse XML and build pages\n", millis());
     file.close();
-    SdMan.remove(filePath.c_str());
+    Storage.remove(filePath.c_str());
     return false;
   }
 
@@ -210,7 +210,7 @@ bool Section::createSectionFile(const int fontId, const float lineCompression, c
   if (hasFailedLutRecords) {
     Serial.printf("[%lu] [SCT] Failed to write LUT due to invalid page positions\n", millis());
     file.close();
-    SdMan.remove(filePath.c_str());
+    Storage.remove(filePath.c_str());
     return false;
   }
 
@@ -223,7 +223,7 @@ bool Section::createSectionFile(const int fontId, const float lineCompression, c
 }
 
 std::unique_ptr<Page> Section::loadPageFromSectionFile() {
-  if (!SdMan.openFileForRead("SCT", filePath, file)) {
+  if (!Storage.openFileForRead("SCT", filePath, file)) {
     return nullptr;
   }
 

lib/Epub/Epub/blocks/TextBlock.h

@@ -1,6 +1,6 @@
 #pragma once
 #include <EpdFontFamily.h>
-#include <SdFat.h>
+#include <HalStorage.h>
 
 #include <list>
 #include <memory>

lib/Epub/Epub/css/CssParser.h

@@ -1,6 +1,6 @@
 #pragma once
 
-#include <SdFat.h>
+#include <HalStorage.h>
 
 #include <string>
 #include <unordered_map>

lib/Epub/Epub/parsers/ChapterHtmlSlimParser.cpp

@@ -1,8 +1,8 @@
 #include "ChapterHtmlSlimParser.h"
 
 #include <GfxRenderer.h>
+#include <HalStorage.h>
 #include <HardwareSerial.h>
-#include <SDCardManager.h>
 #include <expat.h>
 
 #include "../Page.h"
@@ -482,7 +482,7 @@ bool ChapterHtmlSlimParser::parseAndBuildPages() {
   }
 
   FsFile file;
-  if (!SdMan.openFileForRead("EHP", filepath, file)) {
+  if (!Storage.openFileForRead("EHP", filepath, file)) {
     XML_ParserFree(parser);
     return false;
   }

lib/Epub/Epub/parsers/ContentOpfParser.cpp

@@ -36,8 +36,8 @@ ContentOpfParser::~ContentOpfParser() {
   if (tempItemStore) {
     tempItemStore.close();
   }
-  if (SdMan.exists((cachePath + itemCacheFile).c_str())) {
+  if (Storage.exists((cachePath + itemCacheFile).c_str())) {
-    SdMan.remove((cachePath + itemCacheFile).c_str());
+    Storage.remove((cachePath + itemCacheFile).c_str());
   }
   itemIndex.clear();
   itemIndex.shrink_to_fit();
@@ -118,7 +118,7 @@ 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 (!SdMan.openFileForWrite("COF", self->cachePath + itemCacheFile, self->tempItemStore)) {
+    if (!Storage.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());
@@ -128,7 +128,7 @@ void XMLCALL ContentOpfParser::startElement(void* userData, const XML_Char* name
 
   if (self->state == IN_PACKAGE && (strcmp(name, "spine") == 0 || strcmp(name, "opf:spine") == 0)) {
     self->state = IN_SPINE;
-    if (!SdMan.openFileForRead("COF", self->cachePath + itemCacheFile, self->tempItemStore)) {
+    if (!Storage.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());
@@ -149,7 +149,7 @@ void XMLCALL ContentOpfParser::startElement(void* userData, const XML_Char* name
     self->state = IN_GUIDE;
     // TODO Remove print
     Serial.printf("[%lu] [COF] Entering guide state.\n", millis());
-    if (!SdMan.openFileForRead("COF", self->cachePath + itemCacheFile, self->tempItemStore)) {
+    if (!Storage.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());
@@ -232,6 +232,14 @@ void XMLCALL ContentOpfParser::startElement(void* userData, const XML_Char* name
         Serial.printf("[%lu] [COF] Found EPUB 3 nav document: %s\n", millis(), href.c_str());
       }
     }
+
+    // EPUB 3: Check for cover image (properties contains "cover-image")
+    if (!properties.empty() && self->coverItemHref.empty()) {
+      if (properties == "cover-image" || properties.find("cover-image ") == 0 ||
+          properties.find(" cover-image") != std::string::npos) {
+        self->coverItemHref = href;
+      }
+    }
     return;
   }
 

lib/GfxRenderer/Bitmap.h

@@ -1,6 +1,6 @@
 #pragma once
 
-#include <SdFat.h>
+#include <HalStorage.h>
 
 #include <cstdint>
 

lib/GfxRenderer/BitmapHelpers.cpp

@@ -104,3 +104,20 @@ uint8_t quantize1bit(int gray, int x, int y) {
   const int adjustedThreshold = 128 + ((threshold - 128) / 2);  // Range: 64-192
   return (gray >= adjustedThreshold) ? 1 : 0;
 }
+
+// Noise dithering for gradient fills - always uses hash-based noise regardless of global dithering config.
+// Produces smooth-looking gradients on the 4-level e-ink display.
+uint8_t quantizeNoiseDither(int gray, int x, int y) {
+  uint32_t hash = static_cast<uint32_t>(x) * 374761393u + static_cast<uint32_t>(y) * 668265263u;
+  hash = (hash ^ (hash >> 13)) * 1274126177u;
+  const int threshold = static_cast<int>(hash >> 24);
+
+  const int scaled = gray * 3;
+  if (scaled < 255) {
+    return (scaled + threshold >= 255) ? 1 : 0;
+  } else if (scaled < 510) {
+    return ((scaled - 255) + threshold >= 255) ? 2 : 1;
+  } else {
+    return ((scaled - 510) + threshold >= 255) ? 3 : 2;
+  }
+}

lib/GfxRenderer/BitmapHelpers.h

@@ -7,6 +7,7 @@ uint8_t quantize(int gray, int x, int y);
 uint8_t quantizeSimple(int gray);
 uint8_t quantize1bit(int gray, int x, int y);
 int adjustPixel(int gray);
+uint8_t quantizeNoiseDither(int gray, int x, int y);
 
 // 1-bit Atkinson dithering - better quality than noise dithering for thumbnails
 // Error distribution pattern (same as 2-bit but quantizes to 2 levels):

lib/GfxRenderer/GfxRenderer.cpp

@@ -72,6 +72,16 @@ void GfxRenderer::drawPixel(const int x, const int y, const bool state) const {
   }
 }
 
+void GfxRenderer::drawPixelGray(const int x, const int y, const uint8_t val2bit) const {
+  if (renderMode == BW && val2bit < 3) {
+    drawPixel(x, y);
+  } else if (renderMode == GRAYSCALE_MSB && (val2bit == 1 || val2bit == 2)) {
+    drawPixel(x, y, false);
+  } else if (renderMode == GRAYSCALE_LSB && val2bit == 1) {
+    drawPixel(x, y, false);
+  }
+}
+
 int GfxRenderer::getTextWidth(const int fontId, const char* text, const EpdFontFamily::Style style) const {
   if (fontMap.count(fontId) == 0) {
     Serial.printf("[%lu] [GFX] Font %d not found\n", millis(), fontId);
@@ -422,12 +432,20 @@ void GfxRenderer::drawBitmap(const Bitmap& bitmap, const int x, const int y, con
   Serial.printf("[%lu] [GFX] Cropping %dx%d by %dx%d pix, is %s\n", millis(), bitmap.getWidth(), bitmap.getHeight(),
                 cropPixX, cropPixY, bitmap.isTopDown() ? "top-down" : "bottom-up");
 
-  if (maxWidth > 0 && (1.0f - cropX) * bitmap.getWidth() > maxWidth) {
+  const float effectiveWidth = (1.0f - cropX) * bitmap.getWidth();
-    scale = static_cast<float>(maxWidth) / static_cast<float>((1.0f - cropX) * bitmap.getWidth());
+  const float effectiveHeight = (1.0f - cropY) * bitmap.getHeight();
+
+  // Calculate scale factor: supports both downscaling and upscaling when both constraints are provided
+  if (maxWidth > 0 && maxHeight > 0) {
+    const float scaleX = static_cast<float>(maxWidth) / effectiveWidth;
+    const float scaleY = static_cast<float>(maxHeight) / effectiveHeight;
+    scale = std::min(scaleX, scaleY);
+    isScaled = (scale < 0.999f || scale > 1.001f);
+  } else if (maxWidth > 0 && effectiveWidth > static_cast<float>(maxWidth)) {
+    scale = static_cast<float>(maxWidth) / effectiveWidth;
     isScaled = true;
-  }
+  } else if (maxHeight > 0 && effectiveHeight > static_cast<float>(maxHeight)) {
-  if (maxHeight > 0 && (1.0f - cropY) * bitmap.getHeight() > maxHeight) {
+    scale = static_cast<float>(maxHeight) / effectiveHeight;
-    scale = std::min(scale, static_cast<float>(maxHeight) / static_cast<float>((1.0f - cropY) * bitmap.getHeight()));
     isScaled = true;
   }
   Serial.printf("[%lu] [GFX] Scaling by %f - %s\n", millis(), scale, isScaled ? "scaled" : "not scaled");
@@ -448,12 +466,17 @@ void GfxRenderer::drawBitmap(const Bitmap& bitmap, const int x, const int y, con
   for (int bmpY = 0; bmpY < (bitmap.getHeight() - cropPixY); 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 = -cropPixY + (bitmap.isTopDown() ? bmpY : bitmap.getHeight() - 1 - bmpY);
+    const int logicalY = -cropPixY + (bitmap.isTopDown() ? bmpY : bitmap.getHeight() - 1 - bmpY);
+    int screenYStart, screenYEnd;
     if (isScaled) {
-      screenY = std::floor(screenY * scale);
+      screenYStart = static_cast<int>(std::floor(logicalY * scale)) + y;
+      screenYEnd = static_cast<int>(std::floor((logicalY + 1) * scale)) + y;
+    } else {
+      screenYStart = logicalY + y;
+      screenYEnd = screenYStart + 1;
     }
-    screenY += y;  // the offset should not be scaled
+
-    if (screenY >= getScreenHeight()) {
+    if (screenYStart >= getScreenHeight()) {
       break;
     }
 
@@ -464,7 +487,7 @@ void GfxRenderer::drawBitmap(const Bitmap& bitmap, const int x, const int y, con
       return;
     }
 
-    if (screenY < 0) {
+    if (screenYEnd <= 0) {
       continue;
     }
 
@@ -473,27 +496,42 @@ void GfxRenderer::drawBitmap(const Bitmap& bitmap, const int x, const int y, con
       continue;
     }
 
+    const int syStart = std::max(screenYStart, 0);
+    const int syEnd = std::min(screenYEnd, getScreenHeight());
+
     for (int bmpX = cropPixX; bmpX < bitmap.getWidth() - cropPixX; bmpX++) {
-      int screenX = bmpX - cropPixX;
+      const int outX = bmpX - cropPixX;
+      int screenXStart, screenXEnd;
       if (isScaled) {
-        screenX = std::floor(screenX * scale);
+        screenXStart = static_cast<int>(std::floor(outX * scale)) + x;
+        screenXEnd = static_cast<int>(std::floor((outX + 1) * scale)) + x;
+      } else {
+        screenXStart = outX + x;
+        screenXEnd = screenXStart + 1;
       }
-      screenX += x;  // the offset should not be scaled
+
-      if (screenX >= getScreenWidth()) {
+      if (screenXStart >= getScreenWidth()) {
         break;
       }
-      if (screenX < 0) {
+      if (screenXEnd <= 0) {
         continue;
       }
 
       const uint8_t val = outputRow[bmpX / 4] >> (6 - ((bmpX * 2) % 8)) & 0x3;
 
+      const int sxStart = std::max(screenXStart, 0);
+      const int sxEnd = std::min(screenXEnd, getScreenWidth());
+
+      for (int sy = syStart; sy < syEnd; sy++) {
+        for (int sx = sxStart; sx < sxEnd; sx++) {
           if (renderMode == BW && val < 3) {
-        drawPixel(screenX, screenY);
+            drawPixel(sx, sy);
           } else if (renderMode == GRAYSCALE_MSB && (val == 1 || val == 2)) {
-        drawPixel(screenX, screenY, false);
+            drawPixel(sx, sy, false);
           } else if (renderMode == GRAYSCALE_LSB && val == 1) {
-        drawPixel(screenX, screenY, false);
+            drawPixel(sx, sy, false);
+          }
+        }
       }
     }
   }
@@ -506,11 +544,16 @@ void GfxRenderer::drawBitmap1Bit(const Bitmap& bitmap, const int x, const int y,
                                  const int maxHeight) const {
   float scale = 1.0f;
   bool isScaled = false;
-  if (maxWidth > 0 && bitmap.getWidth() > maxWidth) {
+  // Calculate scale factor: supports both downscaling and upscaling when both constraints are provided
+  if (maxWidth > 0 && maxHeight > 0) {
+    const float scaleX = static_cast<float>(maxWidth) / static_cast<float>(bitmap.getWidth());
+    const float scaleY = static_cast<float>(maxHeight) / static_cast<float>(bitmap.getHeight());
+    scale = std::min(scaleX, scaleY);
+    isScaled = (scale < 0.999f || scale > 1.001f);
+  } else if (maxWidth > 0 && bitmap.getWidth() > maxWidth) {
     scale = static_cast<float>(maxWidth) / static_cast<float>(bitmap.getWidth());
     isScaled = true;
-  }
+  } else if (maxHeight > 0 && bitmap.getHeight() > maxHeight) {
-  if (maxHeight > 0 && bitmap.getHeight() > maxHeight) {
     scale = std::min(scale, static_cast<float>(maxHeight) / static_cast<float>(bitmap.getHeight()));
     isScaled = true;
   }
@@ -538,20 +581,37 @@ void GfxRenderer::drawBitmap1Bit(const Bitmap& bitmap, const int x, const int y,
 
     // Calculate screen Y based on whether BMP is top-down or bottom-up
     const int bmpYOffset = bitmap.isTopDown() ? bmpY : bitmap.getHeight() - 1 - bmpY;
-    int screenY = y + (isScaled ? static_cast<int>(std::floor(bmpYOffset * scale)) : bmpYOffset);
+    int screenYStart, screenYEnd;
-    if (screenY >= getScreenHeight()) {
+    if (isScaled) {
+      screenYStart = static_cast<int>(std::floor(bmpYOffset * scale)) + y;
+      screenYEnd = static_cast<int>(std::floor((bmpYOffset + 1) * scale)) + y;
+    } else {
+      screenYStart = bmpYOffset + y;
+      screenYEnd = screenYStart + 1;
+    }
+    if (screenYStart >= getScreenHeight()) {
       continue;  // Continue reading to keep row counter in sync
     }
-    if (screenY < 0) {
+    if (screenYEnd <= 0) {
       continue;
     }
 
+    const int syStart = std::max(screenYStart, 0);
+    const int syEnd = std::min(screenYEnd, getScreenHeight());
+
     for (int bmpX = 0; bmpX < bitmap.getWidth(); bmpX++) {
-      int screenX = x + (isScaled ? static_cast<int>(std::floor(bmpX * scale)) : bmpX);
+      int screenXStart, screenXEnd;
-      if (screenX >= getScreenWidth()) {
+      if (isScaled) {
+        screenXStart = static_cast<int>(std::floor(bmpX * scale)) + x;
+        screenXEnd = static_cast<int>(std::floor((bmpX + 1) * scale)) + x;
+      } else {
+        screenXStart = bmpX + x;
+        screenXEnd = screenXStart + 1;
+      }
+      if (screenXStart >= getScreenWidth()) {
         break;
       }
-      if (screenX < 0) {
+      if (screenXEnd <= 0) {
         continue;
       }
 
@@ -561,7 +621,13 @@ void GfxRenderer::drawBitmap1Bit(const Bitmap& bitmap, const int x, const int y,
       // For 1-bit source: 0 or 1 -> map to black (0,1,2) or white (3)
       // val < 3 means black pixel (draw it)
       if (val < 3) {
-        drawPixel(screenX, screenY, true);
+        const int sxStart = std::max(screenXStart, 0);
+        const int sxEnd = std::min(screenXEnd, getScreenWidth());
+        for (int sy = syStart; sy < syEnd; sy++) {
+          for (int sx = sxStart; sx < sxEnd; sx++) {
+            drawPixel(sx, sy, true);
+          }
+        }
       }
       // White pixels (val == 3) are not drawn (leave background)
     }

lib/GfxRenderer/GfxRenderer.h

@@ -77,6 +77,7 @@ class GfxRenderer {
 
   // Drawing
   void drawPixel(int x, int y, bool state = true) const;
+  void drawPixelGray(int x, int y, uint8_t val2bit) const;
   void drawLine(int x1, int y1, int x2, int y2, bool state = true) const;
   void drawLine(int x1, int y1, int x2, int y2, int lineWidth, bool state) const;
   void drawArc(int maxRadius, int cx, int cy, int xDir, int yDir, int lineWidth, bool state) const;

lib/JpegToBmpConverter/JpegToBmpConverter.cpp

@@ -1,7 +1,7 @@
 #include "JpegToBmpConverter.h"
 
+#include <HalStorage.h>
 #include <HardwareSerial.h>
-#include <SdFat.h>
 #include <picojpeg.h>
 
 #include <cstdio>

lib/KOReaderSync/KOReaderCredentialStore.cpp

@@ -1,8 +1,8 @@
 #include "KOReaderCredentialStore.h"
 
+#include <HalStorage.h>
 #include <HardwareSerial.h>
 #include <MD5Builder.h>
-#include <SDCardManager.h>
 #include <Serialization.h>
 
 // Initialize the static instance
@@ -32,10 +32,10 @@ void KOReaderCredentialStore::obfuscate(std::string& data) const {
 
 bool KOReaderCredentialStore::saveToFile() const {
   // Make sure the directory exists
-  SdMan.mkdir("/.crosspoint");
+  Storage.mkdir("/.crosspoint");
 
   FsFile file;
-  if (!SdMan.openFileForWrite("KRS", KOREADER_FILE, file)) {
+  if (!Storage.openFileForWrite("KRS", KOREADER_FILE, file)) {
     return false;
   }
 
@@ -64,7 +64,7 @@ bool KOReaderCredentialStore::saveToFile() const {
 
 bool KOReaderCredentialStore::loadFromFile() {
   FsFile file;
-  if (!SdMan.openFileForRead("KRS", KOREADER_FILE, file)) {
+  if (!Storage.openFileForRead("KRS", KOREADER_FILE, file)) {
     Serial.printf("[%lu] [KRS] No credentials file found\n", millis());
     return false;
   }

lib/KOReaderSync/KOReaderDocumentId.cpp

@@ -1,8 +1,8 @@
 #include "KOReaderDocumentId.h"
 
+#include <HalStorage.h>
 #include <HardwareSerial.h>
 #include <MD5Builder.h>
-#include <SDCardManager.h>
 
 namespace {
 // Extract filename from path (everything after last '/')
@@ -43,7 +43,7 @@ size_t KOReaderDocumentId::getOffset(int i) {
 
 std::string KOReaderDocumentId::calculate(const std::string& filePath) {
   FsFile file;
-  if (!SdMan.openFileForRead("KODoc", filePath, file)) {
+  if (!Storage.openFileForRead("KODoc", filePath, file)) {
     Serial.printf("[%lu] [KODoc] Failed to open file: %s\n", millis(), filePath.c_str());
     return "";
   }

lib/Serialization/Serialization.h

@@ -1,5 +1,5 @@
 #pragma once
-#include <SdFat.h>
+#include <HalStorage.h>
 
 #include <iostream>
 

lib/Txt/Txt.cpp

@@ -15,13 +15,13 @@ bool Txt::load() {
     return true;
   }
 
-  if (!SdMan.exists(filepath.c_str())) {
+  if (!Storage.exists(filepath.c_str())) {
     Serial.printf("[%lu] [TXT] File does not exist: %s\n", millis(), filepath.c_str());
     return false;
   }
 
   FsFile file;
-  if (!SdMan.openFileForRead("TXT", filepath, file)) {
+  if (!Storage.openFileForRead("TXT", filepath, file)) {
     Serial.printf("[%lu] [TXT] Failed to open file: %s\n", millis(), filepath.c_str());
     return false;
   }
@@ -48,11 +48,11 @@ std::string Txt::getTitle() const {
 }
 
 void Txt::setupCacheDir() const {
-  if (!SdMan.exists(cacheBasePath.c_str())) {
+  if (!Storage.exists(cacheBasePath.c_str())) {
-    SdMan.mkdir(cacheBasePath.c_str());
+    Storage.mkdir(cacheBasePath.c_str());
   }
-  if (!SdMan.exists(cachePath.c_str())) {
+  if (!Storage.exists(cachePath.c_str())) {
-    SdMan.mkdir(cachePath.c_str());
+    Storage.mkdir(cachePath.c_str());
   }
 }
 
@@ -73,7 +73,7 @@ std::string Txt::findCoverImage() const {
   // First priority: look for image with same name as txt file (e.g., mybook.jpg)
   for (const auto& ext : extensions) {
     std::string coverPath = folder + "/" + baseName + ext;
-    if (SdMan.exists(coverPath.c_str())) {
+    if (Storage.exists(coverPath.c_str())) {
       Serial.printf("[%lu] [TXT] Found matching cover image: %s\n", millis(), coverPath.c_str());
       return coverPath;
     }
@@ -84,7 +84,7 @@ std::string Txt::findCoverImage() const {
   for (const auto& name : coverNames) {
     for (const auto& ext : extensions) {
       std::string coverPath = folder + "/" + std::string(name) + ext;
-      if (SdMan.exists(coverPath.c_str())) {
+      if (Storage.exists(coverPath.c_str())) {
         Serial.printf("[%lu] [TXT] Found fallback cover image: %s\n", millis(), coverPath.c_str());
         return coverPath;
       }
@@ -98,7 +98,7 @@ std::string Txt::getCoverBmpPath() const { return cachePath + "/cover.bmp"; }
 
 bool Txt::generateCoverBmp() const {
   // Already generated, return true
-  if (SdMan.exists(getCoverBmpPath().c_str())) {
+  if (Storage.exists(getCoverBmpPath().c_str())) {
     return true;
   }
 
@@ -122,10 +122,10 @@ bool Txt::generateCoverBmp() const {
     // Copy BMP file to cache
     Serial.printf("[%lu] [TXT] Copying BMP cover image to cache\n", millis());
     FsFile src, dst;
-    if (!SdMan.openFileForRead("TXT", coverImagePath, src)) {
+    if (!Storage.openFileForRead("TXT", coverImagePath, src)) {
       return false;
     }
-    if (!SdMan.openFileForWrite("TXT", getCoverBmpPath(), dst)) {
+    if (!Storage.openFileForWrite("TXT", getCoverBmpPath(), dst)) {
       src.close();
       return false;
     }
@@ -144,10 +144,10 @@ bool Txt::generateCoverBmp() const {
     // Convert JPG/JPEG to BMP (same approach as Epub)
     Serial.printf("[%lu] [TXT] Generating BMP from JPG cover image\n", millis());
     FsFile coverJpg, coverBmp;
-    if (!SdMan.openFileForRead("TXT", coverImagePath, coverJpg)) {
+    if (!Storage.openFileForRead("TXT", coverImagePath, coverJpg)) {
       return false;
     }
-    if (!SdMan.openFileForWrite("TXT", getCoverBmpPath(), coverBmp)) {
+    if (!Storage.openFileForWrite("TXT", getCoverBmpPath(), coverBmp)) {
       coverJpg.close();
       return false;
     }
@@ -157,7 +157,7 @@ bool Txt::generateCoverBmp() const {
 
     if (!success) {
       Serial.printf("[%lu] [TXT] Failed to generate BMP from JPG cover image\n", millis());
-      SdMan.remove(getCoverBmpPath().c_str());
+      Storage.remove(getCoverBmpPath().c_str());
     } else {
       Serial.printf("[%lu] [TXT] Generated BMP from JPG cover image\n", millis());
     }
@@ -175,7 +175,7 @@ bool Txt::readContent(uint8_t* buffer, size_t offset, size_t length) const {
   }
 
   FsFile file;
-  if (!SdMan.openFileForRead("TXT", filepath, file)) {
+  if (!Storage.openFileForRead("TXT", filepath, file)) {
     return false;
   }
 

lib/Txt/Txt.h

@@ -1,6 +1,6 @@
 #pragma once
 
-#include <SDCardManager.h>
+#include <HalStorage.h>
 
 #include <memory>
 #include <string>

lib/Xtc/Xtc.cpp

@@ -7,8 +7,8 @@
 
 #include "Xtc.h"
 
+#include <HalStorage.h>
 #include <HardwareSerial.h>
-#include <SDCardManager.h>
 
 bool Xtc::load() {
   Serial.printf("[%lu] [XTC] Loading XTC: %s\n", millis(), filepath.c_str());
@@ -30,12 +30,12 @@ bool Xtc::load() {
 }
 
 bool Xtc::clearCache() const {
-  if (!SdMan.exists(cachePath.c_str())) {
+  if (!Storage.exists(cachePath.c_str())) {
     Serial.printf("[%lu] [XTC] Cache does not exist, no action needed\n", millis());
     return true;
   }
 
-  if (!SdMan.removeDir(cachePath.c_str())) {
+  if (!Storage.removeDir(cachePath.c_str())) {
     Serial.printf("[%lu] [XTC] Failed to clear cache\n", millis());
     return false;
   }
@@ -45,17 +45,17 @@ bool Xtc::clearCache() const {
 }
 
 void Xtc::setupCacheDir() const {
-  if (SdMan.exists(cachePath.c_str())) {
+  if (Storage.exists(cachePath.c_str())) {
     return;
   }
 
   // Create directories recursively
   for (size_t i = 1; i < cachePath.length(); i++) {
     if (cachePath[i] == '/') {
-      SdMan.mkdir(cachePath.substr(0, i).c_str());
+      Storage.mkdir(cachePath.substr(0, i).c_str());
     }
   }
-  SdMan.mkdir(cachePath.c_str());
+  Storage.mkdir(cachePath.c_str());
 }
 
 std::string Xtc::getTitle() const {
@@ -114,7 +114,7 @@ std::string Xtc::getCoverBmpPath() const { return cachePath + "/cover.bmp"; }
 
 bool Xtc::generateCoverBmp() const {
   // Already generated
-  if (SdMan.exists(getCoverBmpPath().c_str())) {
+  if (Storage.exists(getCoverBmpPath().c_str())) {
     return true;
   }
 
@@ -166,7 +166,7 @@ bool Xtc::generateCoverBmp() const {
 
   // Create BMP file
   FsFile coverBmp;
-  if (!SdMan.openFileForWrite("XTC", getCoverBmpPath(), coverBmp)) {
+  if (!Storage.openFileForWrite("XTC", getCoverBmpPath(), coverBmp)) {
     Serial.printf("[%lu] [XTC] Failed to create cover BMP file\n", millis());
     free(pageBuffer);
     return false;
@@ -306,7 +306,7 @@ std::string Xtc::getThumbBmpPath(int height) const { return cachePath + "/thumb_
 
 bool Xtc::generateThumbBmp(int height) const {
   // Already generated
-  if (SdMan.exists(getThumbBmpPath(height).c_str())) {
+  if (Storage.exists(getThumbBmpPath(height).c_str())) {
     return true;
   }
 
@@ -348,8 +348,8 @@ bool Xtc::generateThumbBmp(int height) const {
     // Copy cover.bmp to thumb.bmp
     if (generateCoverBmp()) {
       FsFile src, dst;
-      if (SdMan.openFileForRead("XTC", getCoverBmpPath(), src)) {
+      if (Storage.openFileForRead("XTC", getCoverBmpPath(), src)) {
-        if (SdMan.openFileForWrite("XTC", getThumbBmpPath(height), dst)) {
+        if (Storage.openFileForWrite("XTC", getThumbBmpPath(height), dst)) {
           uint8_t buffer[512];
           while (src.available()) {
             size_t bytesRead = src.read(buffer, sizeof(buffer));
@@ -360,7 +360,7 @@ bool Xtc::generateThumbBmp(int height) const {
         src.close();
       }
       Serial.printf("[%lu] [XTC] Copied cover to thumb (no scaling needed)\n", millis());
-      return SdMan.exists(getThumbBmpPath(height).c_str());
+      return Storage.exists(getThumbBmpPath(height).c_str());
     }
     return false;
   }
@@ -394,7 +394,7 @@ bool Xtc::generateThumbBmp(int height) const {
 
   // Create thumbnail BMP file - use 1-bit format for fast home screen rendering (no gray passes)
   FsFile thumbBmp;
-  if (!SdMan.openFileForWrite("XTC", getThumbBmpPath(height), thumbBmp)) {
+  if (!Storage.openFileForWrite("XTC", getThumbBmpPath(height), thumbBmp)) {
     Serial.printf("[%lu] [XTC] Failed to create thumb BMP file\n", millis());
     free(pageBuffer);
     return false;

lib/Xtc/Xtc/XtcParser.cpp

@@ -8,8 +8,8 @@
 #include "XtcParser.h"
 
 #include <FsHelpers.h>
+#include <HalStorage.h>
 #include <HardwareSerial.h>
-#include <SDCardManager.h>
 
 #include <cstring>
 
@@ -34,7 +34,7 @@ XtcError XtcParser::open(const char* filepath) {
   }
 
   // Open file
-  if (!SdMan.openFileForRead("XTC", filepath, m_file)) {
+  if (!Storage.openFileForRead("XTC", filepath, m_file)) {
     m_lastError = XtcError::FILE_NOT_FOUND;
     return m_lastError;
   }
@@ -444,7 +444,7 @@ XtcError XtcParser::loadPageStreaming(uint32_t pageIndex,
 
 bool XtcParser::isValidXtcFile(const char* filepath) {
   FsFile file;
-  if (!SdMan.openFileForRead("XTC", filepath, file)) {
+  if (!Storage.openFileForRead("XTC", filepath, file)) {
     return false;
   }
 

lib/Xtc/Xtc/XtcParser.h

@@ -7,7 +7,7 @@
 
 #pragma once
 
-#include <SdFat.h>
+#include <HalStorage.h>
 
 #include <functional>
 #include <memory>

lib/ZipFile/ZipFile.cpp

@@ -1,7 +1,7 @@
 #include "ZipFile.h"
 
+#include <HalStorage.h>
 #include <HardwareSerial.h>
-#include <SDCardManager.h>
 #include <miniz.h>
 
 #include <algorithm>
@@ -279,7 +279,7 @@ bool ZipFile::loadZipDetails() {
 }
 
 bool ZipFile::open() {
-  if (!SdMan.openFileForRead("ZIP", filePath, file)) {
+  if (!Storage.openFileForRead("ZIP", filePath, file)) {
     return false;
   }
   return true;

lib/ZipFile/ZipFile.h

@@ -1,5 +1,5 @@
 #pragma once
-#include <SdFat.h>
+#include <HalStorage.h>
 
 #include <string>
 #include <unordered_map>

lib/hal/HalStorage.cpp

@@ -0,0 +1,65 @@
+#include "HalStorage.h"
+
+#include <SDCardManager.h>
+
+#define SDCard SDCardManager::getInstance()
+
+HalStorage HalStorage::instance;
+
+HalStorage::HalStorage() {}
+
+bool HalStorage::begin() { return SDCard.begin(); }
+
+bool HalStorage::ready() const { return SDCard.ready(); }
+
+std::vector<String> HalStorage::listFiles(const char* path, int maxFiles) { return SDCard.listFiles(path, maxFiles); }
+
+String HalStorage::readFile(const char* path) { return SDCard.readFile(path); }
+
+bool HalStorage::readFileToStream(const char* path, Print& out, size_t chunkSize) {
+  return SDCard.readFileToStream(path, out, chunkSize);
+}
+
+size_t HalStorage::readFileToBuffer(const char* path, char* buffer, size_t bufferSize, size_t maxBytes) {
+  return SDCard.readFileToBuffer(path, buffer, bufferSize, maxBytes);
+}
+
+bool HalStorage::writeFile(const char* path, const String& content) { return SDCard.writeFile(path, content); }
+
+bool HalStorage::ensureDirectoryExists(const char* path) { return SDCard.ensureDirectoryExists(path); }
+
+FsFile HalStorage::open(const char* path, const oflag_t oflag) { return SDCard.open(path, oflag); }
+
+bool HalStorage::mkdir(const char* path, const bool pFlag) { return SDCard.mkdir(path, pFlag); }
+
+bool HalStorage::exists(const char* path) { return SDCard.exists(path); }
+
+bool HalStorage::remove(const char* path) { return SDCard.remove(path); }
+
+bool HalStorage::rmdir(const char* path) { return SDCard.rmdir(path); }
+
+bool HalStorage::openFileForRead(const char* moduleName, const char* path, FsFile& file) {
+  return SDCard.openFileForRead(moduleName, path, file);
+}
+
+bool HalStorage::openFileForRead(const char* moduleName, const std::string& path, FsFile& file) {
+  return openFileForRead(moduleName, path.c_str(), file);
+}
+
+bool HalStorage::openFileForRead(const char* moduleName, const String& path, FsFile& file) {
+  return openFileForRead(moduleName, path.c_str(), file);
+}
+
+bool HalStorage::openFileForWrite(const char* moduleName, const char* path, FsFile& file) {
+  return SDCard.openFileForWrite(moduleName, path, file);
+}
+
+bool HalStorage::openFileForWrite(const char* moduleName, const std::string& path, FsFile& file) {
+  return openFileForWrite(moduleName, path.c_str(), file);
+}
+
+bool HalStorage::openFileForWrite(const char* moduleName, const String& path, FsFile& file) {
+  return openFileForWrite(moduleName, path.c_str(), file);
+}
+
+bool HalStorage::removeDir(const char* path) { return SDCard.removeDir(path); }

lib/hal/HalStorage.h

@@ -0,0 +1,54 @@
+#pragma once
+
+#include <SDCardManager.h>
+
+#include <vector>
+
+class HalStorage {
+ public:
+  HalStorage();
+  bool begin();
+  bool ready() const;
+  std::vector<String> listFiles(const char* path = "/", int maxFiles = 200);
+  // Read the entire file at `path` into a String. Returns empty string on failure.
+  String readFile(const char* path);
+  // Low-memory helpers:
+  // Stream the file contents to a `Print` (e.g. `Serial`, or any `Print`-derived object).
+  // Returns true on success, false on failure.
+  bool readFileToStream(const char* path, Print& out, size_t chunkSize = 256);
+  // Read up to `bufferSize-1` bytes into `buffer`, null-terminating it. Returns bytes read.
+  size_t readFileToBuffer(const char* path, char* buffer, size_t bufferSize, size_t maxBytes = 0);
+  // Write a string to `path` on the SD card. Overwrites existing file.
+  // Returns true on success.
+  bool writeFile(const char* path, const String& content);
+  // Ensure a directory exists, creating it if necessary. Returns true on success.
+  bool ensureDirectoryExists(const char* path);
+
+  FsFile open(const char* path, const oflag_t oflag = O_RDONLY);
+  bool mkdir(const char* path, const bool pFlag = true);
+  bool exists(const char* path);
+  bool remove(const char* path);
+  bool rmdir(const char* path);
+
+  bool openFileForRead(const char* moduleName, const char* path, FsFile& file);
+  bool openFileForRead(const char* moduleName, const std::string& path, FsFile& file);
+  bool openFileForRead(const char* moduleName, const String& path, FsFile& file);
+  bool openFileForWrite(const char* moduleName, const char* path, FsFile& file);
+  bool openFileForWrite(const char* moduleName, const std::string& path, FsFile& file);
+  bool openFileForWrite(const char* moduleName, const String& path, FsFile& file);
+  bool removeDir(const char* path);
+
+  static HalStorage& getInstance() { return instance; }
+
+ private:
+  static HalStorage instance;
+
+  bool initialized = false;
+};
+
+#define Storage HalStorage::getInstance()
+
+// Downstream code must use Storage instead of SdMan
+#ifdef SdMan
+#undef SdMan
+#endif

src/CrossPointSettings.cpp

@@ -1,7 +1,7 @@
 #include "CrossPointSettings.h"
 
+#include <HalStorage.h>
 #include <HardwareSerial.h>
-#include <SDCardManager.h>
 #include <Serialization.h>
 
 #include <cstring>
@@ -22,7 +22,7 @@ void readAndValidate(FsFile& file, uint8_t& member, const uint8_t maxValue) {
 namespace {
 constexpr uint8_t SETTINGS_FILE_VERSION = 1;
 // Increment this when adding new persisted settings fields
-constexpr uint8_t SETTINGS_COUNT = 30;
+constexpr uint8_t SETTINGS_COUNT = 32;
 constexpr char SETTINGS_FILE[] = "/.crosspoint/settings.bin";
 
 // Validate front button mapping to ensure each hardware button is unique.
@@ -79,10 +79,10 @@ void applyLegacyFrontButtonLayout(CrossPointSettings& settings) {
 
 bool CrossPointSettings::saveToFile() const {
   // Make sure the directory exists
-  SdMan.mkdir("/.crosspoint");
+  Storage.mkdir("/.crosspoint");
 
   FsFile outputFile;
-  if (!SdMan.openFileForWrite("CPS", SETTINGS_FILE, outputFile)) {
+  if (!Storage.openFileForWrite("CPS", SETTINGS_FILE, outputFile)) {
     return false;
   }
 
@@ -118,6 +118,8 @@ bool CrossPointSettings::saveToFile() const {
   serialization::writePod(outputFile, frontButtonRight);
   serialization::writePod(outputFile, fadingFix);
   serialization::writePod(outputFile, embeddedStyle);
+  serialization::writePod(outputFile, sleepScreenLetterboxFill);
+  serialization::writePod(outputFile, sleepScreenGradientDir);
   // New fields added at end for backward compatibility
   outputFile.close();
 
@@ -127,7 +129,7 @@ bool CrossPointSettings::saveToFile() const {
 
 bool CrossPointSettings::loadFromFile() {
   FsFile inputFile;
-  if (!SdMan.openFileForRead("CPS", SETTINGS_FILE, inputFile)) {
+  if (!Storage.openFileForRead("CPS", SETTINGS_FILE, inputFile)) {
     return false;
   }
 
@@ -223,6 +225,10 @@ bool CrossPointSettings::loadFromFile() {
     if (++settingsRead >= fileSettingsCount) break;
     serialization::readPod(inputFile, embeddedStyle);
     if (++settingsRead >= fileSettingsCount) break;
+    readAndValidate(inputFile, sleepScreenLetterboxFill, SLEEP_SCREEN_LETTERBOX_FILL_COUNT);
+    if (++settingsRead >= fileSettingsCount) break;
+    readAndValidate(inputFile, sleepScreenGradientDir, SLEEP_SCREEN_GRADIENT_DIR_COUNT);
+    if (++settingsRead >= fileSettingsCount) break;
     // New fields added at end for backward compatibility
   } while (false);
 

src/CrossPointSettings.h

@@ -31,6 +31,14 @@ class CrossPointSettings {
     INVERTED_BLACK_AND_WHITE = 2,
     SLEEP_SCREEN_COVER_FILTER_COUNT
   };
+  enum SLEEP_SCREEN_LETTERBOX_FILL {
+    LETTERBOX_NONE = 0,
+    LETTERBOX_SOLID = 1,
+    LETTERBOX_BLENDED = 2,
+    LETTERBOX_GRADIENT = 3,
+    SLEEP_SCREEN_LETTERBOX_FILL_COUNT
+  };
+  enum SLEEP_SCREEN_GRADIENT_DIR { GRADIENT_TO_WHITE = 0, GRADIENT_TO_BLACK = 1, SLEEP_SCREEN_GRADIENT_DIR_COUNT };
 
   // Status bar display type enum
   enum STATUS_BAR_MODE {
@@ -125,6 +133,10 @@ class CrossPointSettings {
   uint8_t sleepScreenCoverMode = FIT;
   // Sleep screen cover filter
   uint8_t sleepScreenCoverFilter = NO_FILTER;
+  // Sleep screen letterbox fill mode (None / Solid / Blended / Gradient)
+  uint8_t sleepScreenLetterboxFill = LETTERBOX_GRADIENT;
+  // Sleep screen gradient direction (towards white or black)
+  uint8_t sleepScreenGradientDir = GRADIENT_TO_WHITE;
   // Status bar settings
   uint8_t statusBar = FULL;
   // Text rendering settings

src/CrossPointState.cpp

@@ -1,7 +1,7 @@
 #include "CrossPointState.h"
 
+#include <HalStorage.h>
 #include <HardwareSerial.h>
-#include <SDCardManager.h>
 #include <Serialization.h>
 
 namespace {
@@ -13,7 +13,7 @@ CrossPointState CrossPointState::instance;
 
 bool CrossPointState::saveToFile() const {
   FsFile outputFile;
-  if (!SdMan.openFileForWrite("CPS", STATE_FILE, outputFile)) {
+  if (!Storage.openFileForWrite("CPS", STATE_FILE, outputFile)) {
     return false;
   }
 
@@ -28,7 +28,7 @@ bool CrossPointState::saveToFile() const {
 
 bool CrossPointState::loadFromFile() {
   FsFile inputFile;
-  if (!SdMan.openFileForRead("CPS", STATE_FILE, inputFile)) {
+  if (!Storage.openFileForRead("CPS", STATE_FILE, inputFile)) {
     return false;
   }
 

src/RecentBooksStore.cpp

@@ -1,8 +1,8 @@
 #include "RecentBooksStore.h"
 
 #include <Epub.h>
+#include <HalStorage.h>
 #include <HardwareSerial.h>
-#include <SDCardManager.h>
 #include <Serialization.h>
 #include <Xtc.h>
 
@@ -53,10 +53,10 @@ void RecentBooksStore::updateBook(const std::string& path, const std::string& ti
 
 bool RecentBooksStore::saveToFile() const {
   // Make sure the directory exists
-  SdMan.mkdir("/.crosspoint");
+  Storage.mkdir("/.crosspoint");
 
   FsFile outputFile;
-  if (!SdMan.openFileForWrite("RBS", RECENT_BOOKS_FILE, outputFile)) {
+  if (!Storage.openFileForWrite("RBS", RECENT_BOOKS_FILE, outputFile)) {
     return false;
   }
 
@@ -106,7 +106,7 @@ RecentBook RecentBooksStore::getDataFromBook(std::string path) const {
 
 bool RecentBooksStore::loadFromFile() {
   FsFile inputFile;
-  if (!SdMan.openFileForRead("RBS", RECENT_BOOKS_FILE, inputFile)) {
+  if (!Storage.openFileForRead("RBS", RECENT_BOOKS_FILE, inputFile)) {
     return false;
   }
 

src/SettingsList.h

@@ -0,0 +1,105 @@
+#pragma once
+
+#include <vector>
+
+#include "CrossPointSettings.h"
+#include "KOReaderCredentialStore.h"
+#include "activities/settings/SettingsActivity.h"
+
+// Shared settings list used by both the device settings UI and the web settings API.
+// Each entry has a key (for JSON API) and category (for grouping).
+// ACTION-type entries and entries without a key are device-only.
+inline std::vector<SettingInfo> getSettingsList() {
+  return {
+      // --- Display ---
+      SettingInfo::Enum("Sleep Screen", &CrossPointSettings::sleepScreen,
+                        {"Dark", "Light", "Custom", "Cover", "None", "Cover + Custom"}, "sleepScreen", "Display"),
+      SettingInfo::Enum("Sleep Screen Cover Mode", &CrossPointSettings::sleepScreenCoverMode, {"Fit", "Crop"},
+                        "sleepScreenCoverMode", "Display"),
+      SettingInfo::Enum("Sleep Screen Cover Filter", &CrossPointSettings::sleepScreenCoverFilter,
+                        {"None", "Contrast", "Inverted"}, "sleepScreenCoverFilter", "Display"),
+      SettingInfo::Enum("Letterbox Fill", &CrossPointSettings::sleepScreenLetterboxFill,
+                        {"None", "Solid", "Blended", "Gradient"}, "sleepScreenLetterboxFill", "Display"),
+      SettingInfo::Enum("Gradient Direction", &CrossPointSettings::sleepScreenGradientDir, {"To White", "To Black"},
+                        "sleepScreenGradientDir", "Display"),
+      SettingInfo::Enum(
+          "Status Bar", &CrossPointSettings::statusBar,
+          {"None", "No Progress", "Full w/ Percentage", "Full w/ Book Bar", "Book Bar Only", "Full w/ Chapter Bar"},
+          "statusBar", "Display"),
+      SettingInfo::Enum("Hide Battery %", &CrossPointSettings::hideBatteryPercentage, {"Never", "In Reader", "Always"},
+                        "hideBatteryPercentage", "Display"),
+      SettingInfo::Enum("Refresh Frequency", &CrossPointSettings::refreshFrequency,
+                        {"1 page", "5 pages", "10 pages", "15 pages", "30 pages"}, "refreshFrequency", "Display"),
+      SettingInfo::Enum("UI Theme", &CrossPointSettings::uiTheme, {"Classic", "Lyra"}, "uiTheme", "Display"),
+      SettingInfo::Toggle("Sunlight Fading Fix", &CrossPointSettings::fadingFix, "fadingFix", "Display"),
+
+      // --- Reader ---
+      SettingInfo::Enum("Font Family", &CrossPointSettings::fontFamily, {"Bookerly", "Noto Sans", "Open Dyslexic"},
+                        "fontFamily", "Reader"),
+      SettingInfo::Enum("Font Size", &CrossPointSettings::fontSize, {"Small", "Medium", "Large", "X Large"}, "fontSize",
+                        "Reader"),
+      SettingInfo::Enum("Line Spacing", &CrossPointSettings::lineSpacing, {"Tight", "Normal", "Wide"}, "lineSpacing",
+                        "Reader"),
+      SettingInfo::Value("Screen Margin", &CrossPointSettings::screenMargin, {5, 40, 5}, "screenMargin", "Reader"),
+      SettingInfo::Enum("Paragraph Alignment", &CrossPointSettings::paragraphAlignment,
+                        {"Justify", "Left", "Center", "Right", "Book's Style"}, "paragraphAlignment", "Reader"),
+      SettingInfo::Toggle("Book's Embedded Style", &CrossPointSettings::embeddedStyle, "embeddedStyle", "Reader"),
+      SettingInfo::Toggle("Hyphenation", &CrossPointSettings::hyphenationEnabled, "hyphenationEnabled", "Reader"),
+      SettingInfo::Enum("Reading Orientation", &CrossPointSettings::orientation,
+                        {"Portrait", "Landscape CW", "Inverted", "Landscape CCW"}, "orientation", "Reader"),
+      SettingInfo::Toggle("Extra Paragraph Spacing", &CrossPointSettings::extraParagraphSpacing,
+                          "extraParagraphSpacing", "Reader"),
+      SettingInfo::Toggle("Text Anti-Aliasing", &CrossPointSettings::textAntiAliasing, "textAntiAliasing", "Reader"),
+
+      // --- Controls ---
+      SettingInfo::Enum("Side Button Layout (reader)", &CrossPointSettings::sideButtonLayout,
+                        {"Prev, Next", "Next, Prev"}, "sideButtonLayout", "Controls"),
+      SettingInfo::Toggle("Long-press Chapter Skip", &CrossPointSettings::longPressChapterSkip, "longPressChapterSkip",
+                          "Controls"),
+      SettingInfo::Enum("Short Power Button Click", &CrossPointSettings::shortPwrBtn, {"Ignore", "Sleep", "Page Turn"},
+                        "shortPwrBtn", "Controls"),
+
+      // --- System ---
+      SettingInfo::Enum("Time to Sleep", &CrossPointSettings::sleepTimeout,
+                        {"1 min", "5 min", "10 min", "15 min", "30 min"}, "sleepTimeout", "System"),
+
+      // --- KOReader Sync (web-only, uses KOReaderCredentialStore) ---
+      SettingInfo::DynamicString(
+          "KOReader Username", [] { return KOREADER_STORE.getUsername(); },
+          [](const std::string& v) {
+            KOREADER_STORE.setCredentials(v, KOREADER_STORE.getPassword());
+            KOREADER_STORE.saveToFile();
+          },
+          "koUsername", "KOReader Sync"),
+      SettingInfo::DynamicString(
+          "KOReader Password", [] { return KOREADER_STORE.getPassword(); },
+          [](const std::string& v) {
+            KOREADER_STORE.setCredentials(KOREADER_STORE.getUsername(), v);
+            KOREADER_STORE.saveToFile();
+          },
+          "koPassword", "KOReader Sync"),
+      SettingInfo::DynamicString(
+          "Sync Server URL", [] { return KOREADER_STORE.getServerUrl(); },
+          [](const std::string& v) {
+            KOREADER_STORE.setServerUrl(v);
+            KOREADER_STORE.saveToFile();
+          },
+          "koServerUrl", "KOReader Sync"),
+      SettingInfo::DynamicEnum(
+          "Document Matching", {"Filename", "Binary"},
+          [] { return static_cast<uint8_t>(KOREADER_STORE.getMatchMethod()); },
+          [](uint8_t v) {
+            KOREADER_STORE.setMatchMethod(static_cast<DocumentMatchMethod>(v));
+            KOREADER_STORE.saveToFile();
+          },
+          "koMatchMethod", "KOReader Sync"),
+
+      // --- OPDS Browser (web-only, uses CrossPointSettings char arrays) ---
+      SettingInfo::String("OPDS Server URL", SETTINGS.opdsServerUrl, sizeof(SETTINGS.opdsServerUrl), "opdsServerUrl",
+                          "OPDS Browser"),
+      SettingInfo::String("OPDS Username", SETTINGS.opdsUsername, sizeof(SETTINGS.opdsUsername), "opdsUsername",
+                          "OPDS Browser"),
+      SettingInfo::String("OPDS Password", SETTINGS.opdsPassword, sizeof(SETTINGS.opdsPassword), "opdsPassword",
+                          "OPDS Browser"),
+  };
+}

src/WifiCredentialStore.cpp

@@ -1,7 +1,7 @@
 #include "WifiCredentialStore.h"
 
+#include <HalStorage.h>
 #include <HardwareSerial.h>
-#include <SDCardManager.h>
 #include <Serialization.h>
 
 // Initialize the static instance
@@ -29,10 +29,10 @@ void WifiCredentialStore::obfuscate(std::string& data) const {
 
 bool WifiCredentialStore::saveToFile() const {
   // Make sure the directory exists
-  SdMan.mkdir("/.crosspoint");
+  Storage.mkdir("/.crosspoint");
 
   FsFile file;
-  if (!SdMan.openFileForWrite("WCS", WIFI_FILE, file)) {
+  if (!Storage.openFileForWrite("WCS", WIFI_FILE, file)) {
     return false;
   }
 
@@ -60,7 +60,7 @@ bool WifiCredentialStore::saveToFile() const {
 
 bool WifiCredentialStore::loadFromFile() {
   FsFile file;
-  if (!SdMan.openFileForRead("WCS", WIFI_FILE, file)) {
+  if (!Storage.openFileForRead("WCS", WIFI_FILE, file)) {
     return false;
   }
 

src/activities/boot_sleep/SleepActivity.cpp

@@ -1,11 +1,15 @@
 #include "SleepActivity.h"
 
+#include <BitmapHelpers.h>
 #include <Epub.h>
 #include <GfxRenderer.h>
-#include <SDCardManager.h>
+#include <HalStorage.h>
+#include <Serialization.h>
 #include <Txt.h>
 #include <Xtc.h>
 
+#include <algorithm>
+
 #include "CrossPointSettings.h"
 #include "CrossPointState.h"
 #include "components/UITheme.h"
@@ -13,6 +17,364 @@
 #include "images/Logo120.h"
 #include "util/StringUtils.h"
 
+namespace {
+
+// Number of source pixels along the image edge to average for the gradient color
+constexpr int EDGE_SAMPLE_DEPTH = 20;
+
+// Map a 2-bit quantized pixel value to an 8-bit grayscale value
+constexpr uint8_t val2bitToGray(uint8_t val2bit) { return val2bit * 85; }
+
+// Edge gradient data produced by sampleBitmapEdges and consumed by drawLetterboxGradients.
+// edgeA is the "first" edge (top or left), edgeB is the "second" edge (bottom or right).
+struct LetterboxGradientData {
+  uint8_t* edgeA = nullptr;
+  uint8_t* edgeB = nullptr;
+  int edgeCount = 0;
+  int letterboxA = 0;       // pixel size of the first letterbox area (top or left)
+  int letterboxB = 0;       // pixel size of the second letterbox area (bottom or right)
+  bool horizontal = false;  // true = top/bottom letterbox, false = left/right
+
+  void free() {
+    ::free(edgeA);
+    ::free(edgeB);
+    edgeA = nullptr;
+    edgeB = nullptr;
+  }
+};
+
+// Binary cache version for edge data files
+constexpr uint8_t EDGE_CACHE_VERSION = 1;
+
+// Load cached edge data from a binary file. Returns true if the cache was valid and loaded successfully.
+// Validates cache version and screen dimensions to detect stale data.
+bool loadEdgeCache(const std::string& path, int screenWidth, int screenHeight, LetterboxGradientData& data) {
+  FsFile file;
+  if (!Storage.openFileForRead("SLP", path, file)) return false;
+
+  uint8_t version;
+  serialization::readPod(file, version);
+  if (version != EDGE_CACHE_VERSION) {
+    file.close();
+    return false;
+  }
+
+  uint16_t cachedW, cachedH;
+  serialization::readPod(file, cachedW);
+  serialization::readPod(file, cachedH);
+  if (cachedW != static_cast<uint16_t>(screenWidth) || cachedH != static_cast<uint16_t>(screenHeight)) {
+    file.close();
+    return false;
+  }
+
+  uint8_t horizontal;
+  serialization::readPod(file, horizontal);
+  data.horizontal = (horizontal != 0);
+
+  uint16_t edgeCount;
+  serialization::readPod(file, edgeCount);
+  data.edgeCount = edgeCount;
+
+  int16_t lbA, lbB;
+  serialization::readPod(file, lbA);
+  serialization::readPod(file, lbB);
+  data.letterboxA = lbA;
+  data.letterboxB = lbB;
+
+  if (edgeCount == 0 || edgeCount > 2048) {
+    file.close();
+    return false;
+  }
+
+  data.edgeA = static_cast<uint8_t*>(malloc(edgeCount));
+  data.edgeB = static_cast<uint8_t*>(malloc(edgeCount));
+  if (!data.edgeA || !data.edgeB) {
+    data.free();
+    file.close();
+    return false;
+  }
+
+  if (file.read(data.edgeA, edgeCount) != static_cast<int>(edgeCount) ||
+      file.read(data.edgeB, edgeCount) != static_cast<int>(edgeCount)) {
+    data.free();
+    file.close();
+    return false;
+  }
+
+  file.close();
+  Serial.printf("[%lu] [SLP] Loaded edge cache from %s (%d edges)\n", millis(), path.c_str(), edgeCount);
+  return true;
+}
+
+// Save edge data to a binary cache file for reuse on subsequent sleep screens.
+bool saveEdgeCache(const std::string& path, int screenWidth, int screenHeight, const LetterboxGradientData& data) {
+  if (!data.edgeA || !data.edgeB || data.edgeCount <= 0) return false;
+
+  FsFile file;
+  if (!Storage.openFileForWrite("SLP", path, file)) return false;
+
+  serialization::writePod(file, EDGE_CACHE_VERSION);
+  serialization::writePod(file, static_cast<uint16_t>(screenWidth));
+  serialization::writePod(file, static_cast<uint16_t>(screenHeight));
+  serialization::writePod(file, static_cast<uint8_t>(data.horizontal ? 1 : 0));
+  serialization::writePod(file, static_cast<uint16_t>(data.edgeCount));
+  serialization::writePod(file, static_cast<int16_t>(data.letterboxA));
+  serialization::writePod(file, static_cast<int16_t>(data.letterboxB));
+  file.write(data.edgeA, data.edgeCount);
+  file.write(data.edgeB, data.edgeCount);
+  file.close();
+
+  Serial.printf("[%lu] [SLP] Saved edge cache to %s (%d edges)\n", millis(), path.c_str(), data.edgeCount);
+  return true;
+}
+
+// Read the bitmap once to sample the first/last EDGE_SAMPLE_DEPTH rows or columns.
+// Returns edge color arrays in source pixel resolution.  Caller must call data.free() when done.
+// After sampling the bitmap is rewound via rewindToData().
+LetterboxGradientData sampleBitmapEdges(const Bitmap& bitmap, int imgX, int imgY, int pageWidth, int pageHeight,
+                                        float scale, float cropX, float cropY) {
+  LetterboxGradientData data;
+
+  const int cropPixX = static_cast<int>(std::floor(bitmap.getWidth() * cropX / 2.0f));
+  const int cropPixY = static_cast<int>(std::floor(bitmap.getHeight() * cropY / 2.0f));
+  const int visibleWidth = bitmap.getWidth() - 2 * cropPixX;
+  const int visibleHeight = bitmap.getHeight() - 2 * cropPixY;
+
+  if (visibleWidth <= 0 || visibleHeight <= 0) return data;
+
+  const int outputRowSize = (bitmap.getWidth() + 3) / 4;
+  auto* outputRow = static_cast<uint8_t*>(malloc(outputRowSize));
+  auto* rowBytes = static_cast<uint8_t*>(malloc(bitmap.getRowBytes()));
+  if (!outputRow || !rowBytes) {
+    ::free(outputRow);
+    ::free(rowBytes);
+    return data;
+  }
+
+  if (imgY > 0) {
+    // Top/bottom letterboxing -- sample per-column averages of first/last N rows
+    data.horizontal = true;
+    data.edgeCount = visibleWidth;
+    const int scaledHeight = static_cast<int>(std::round(static_cast<float>(visibleHeight) * scale));
+    data.letterboxA = imgY;
+    data.letterboxB = pageHeight - imgY - scaledHeight;
+    if (data.letterboxB < 0) data.letterboxB = 0;
+
+    const int sampleRows = std::min(EDGE_SAMPLE_DEPTH, visibleHeight);
+
+    auto* accumTop = static_cast<uint32_t*>(calloc(visibleWidth, sizeof(uint32_t)));
+    auto* accumBot = static_cast<uint32_t*>(calloc(visibleWidth, sizeof(uint32_t)));
+    data.edgeA = static_cast<uint8_t*>(malloc(visibleWidth));
+    data.edgeB = static_cast<uint8_t*>(malloc(visibleWidth));
+
+    if (!accumTop || !accumBot || !data.edgeA || !data.edgeB) {
+      ::free(accumTop);
+      ::free(accumBot);
+      data.free();
+      ::free(outputRow);
+      ::free(rowBytes);
+      return data;
+    }
+
+    for (int bmpY = 0; bmpY < bitmap.getHeight(); bmpY++) {
+      if (bitmap.readNextRow(outputRow, rowBytes) != BmpReaderError::Ok) break;
+      const int logicalY = bitmap.isTopDown() ? bmpY : bitmap.getHeight() - 1 - bmpY;
+      if (logicalY < cropPixY || logicalY >= bitmap.getHeight() - cropPixY) continue;
+      const int outY = logicalY - cropPixY;
+
+      const bool inTop = (outY < sampleRows);
+      const bool inBot = (outY >= visibleHeight - sampleRows);
+      if (!inTop && !inBot) continue;
+
+      for (int bmpX = cropPixX; bmpX < bitmap.getWidth() - cropPixX; bmpX++) {
+        const int outX = bmpX - cropPixX;
+        const uint8_t val = (outputRow[bmpX / 4] >> (6 - ((bmpX * 2) % 8))) & 0x3;
+        const uint8_t gray = val2bitToGray(val);
+        if (inTop) accumTop[outX] += gray;
+        if (inBot) accumBot[outX] += gray;
+      }
+    }
+
+    for (int i = 0; i < visibleWidth; i++) {
+      data.edgeA[i] = static_cast<uint8_t>(accumTop[i] / sampleRows);
+      data.edgeB[i] = static_cast<uint8_t>(accumBot[i] / sampleRows);
+    }
+    ::free(accumTop);
+    ::free(accumBot);
+
+  } else if (imgX > 0) {
+    // Left/right letterboxing -- sample per-row averages of first/last N columns
+    data.horizontal = false;
+    data.edgeCount = visibleHeight;
+    const int scaledWidth = static_cast<int>(std::round(static_cast<float>(visibleWidth) * scale));
+    data.letterboxA = imgX;
+    data.letterboxB = pageWidth - imgX - scaledWidth;
+    if (data.letterboxB < 0) data.letterboxB = 0;
+
+    const int sampleCols = std::min(EDGE_SAMPLE_DEPTH, visibleWidth);
+
+    auto* accumLeft = static_cast<uint32_t*>(calloc(visibleHeight, sizeof(uint32_t)));
+    auto* accumRight = static_cast<uint32_t*>(calloc(visibleHeight, sizeof(uint32_t)));
+    data.edgeA = static_cast<uint8_t*>(malloc(visibleHeight));
+    data.edgeB = static_cast<uint8_t*>(malloc(visibleHeight));
+
+    if (!accumLeft || !accumRight || !data.edgeA || !data.edgeB) {
+      ::free(accumLeft);
+      ::free(accumRight);
+      data.free();
+      ::free(outputRow);
+      ::free(rowBytes);
+      return data;
+    }
+
+    for (int bmpY = 0; bmpY < bitmap.getHeight(); bmpY++) {
+      if (bitmap.readNextRow(outputRow, rowBytes) != BmpReaderError::Ok) break;
+      const int logicalY = bitmap.isTopDown() ? bmpY : bitmap.getHeight() - 1 - bmpY;
+      if (logicalY < cropPixY || logicalY >= bitmap.getHeight() - cropPixY) continue;
+      const int outY = logicalY - cropPixY;
+
+      // Sample left edge columns
+      for (int bmpX = cropPixX; bmpX < cropPixX + sampleCols; bmpX++) {
+        const uint8_t val = (outputRow[bmpX / 4] >> (6 - ((bmpX * 2) % 8))) & 0x3;
+        accumLeft[outY] += val2bitToGray(val);
+      }
+      // Sample right edge columns
+      for (int bmpX = bitmap.getWidth() - cropPixX - sampleCols; bmpX < bitmap.getWidth() - cropPixX; bmpX++) {
+        const uint8_t val = (outputRow[bmpX / 4] >> (6 - ((bmpX * 2) % 8))) & 0x3;
+        accumRight[outY] += val2bitToGray(val);
+      }
+    }
+
+    for (int i = 0; i < visibleHeight; i++) {
+      data.edgeA[i] = static_cast<uint8_t>(accumLeft[i] / sampleCols);
+      data.edgeB[i] = static_cast<uint8_t>(accumRight[i] / sampleCols);
+    }
+    ::free(accumLeft);
+    ::free(accumRight);
+  }
+
+  ::free(outputRow);
+  ::free(rowBytes);
+  bitmap.rewindToData();
+  return data;
+}
+
+// Draw dithered fills in the letterbox areas using the sampled edge colors.
+// fillMode selects the fill algorithm: SOLID (single dominant shade), BLENDED (per-pixel edge color),
+// or GRADIENT (per-pixel edge color interpolated toward targetColor).
+// targetColor is the color the gradient fades toward (255=white, 0=black); only used in GRADIENT mode.
+// Must be called once per render pass (BW, GRAYSCALE_LSB, GRAYSCALE_MSB).
+void drawLetterboxFill(GfxRenderer& renderer, const LetterboxGradientData& data, float scale, uint8_t fillMode,
+                       int targetColor) {
+  if (!data.edgeA || !data.edgeB || data.edgeCount <= 0) return;
+
+  const bool isSolid = (fillMode == CrossPointSettings::SLEEP_SCREEN_LETTERBOX_FILL::LETTERBOX_SOLID);
+  const bool isGradient = (fillMode == CrossPointSettings::SLEEP_SCREEN_LETTERBOX_FILL::LETTERBOX_GRADIENT);
+
+  // For SOLID mode, compute the dominant (average) shade for each edge once
+  uint8_t solidColorA = 0, solidColorB = 0;
+  if (isSolid) {
+    uint32_t sumA = 0, sumB = 0;
+    for (int i = 0; i < data.edgeCount; i++) {
+      sumA += data.edgeA[i];
+      sumB += data.edgeB[i];
+    }
+    solidColorA = static_cast<uint8_t>(sumA / data.edgeCount);
+    solidColorB = static_cast<uint8_t>(sumB / data.edgeCount);
+  }
+
+  // Helper: compute gray value for a pixel given the edge color and interpolation factor t (0..1)
+  // GRADIENT interpolates from edgeColor toward targetColor; SOLID and BLENDED return edgeColor directly.
+  auto computeGray = [&](int edgeColor, float t) -> int {
+    if (isGradient) return edgeColor + static_cast<int>(static_cast<float>(targetColor - edgeColor) * t);
+    return edgeColor;
+  };
+
+  if (data.horizontal) {
+    // Top letterbox
+    if (data.letterboxA > 0) {
+      const int imgTopY = data.letterboxA;
+      for (int screenY = 0; screenY < imgTopY; screenY++) {
+        const float t = static_cast<float>(imgTopY - screenY) / static_cast<float>(imgTopY);
+        for (int screenX = 0; screenX < renderer.getScreenWidth(); screenX++) {
+          int edgeColor;
+          if (isSolid) {
+            edgeColor = solidColorA;
+          } else {
+            int srcCol = static_cast<int>(screenX / scale);
+            srcCol = std::max(0, std::min(srcCol, data.edgeCount - 1));
+            edgeColor = data.edgeA[srcCol];
+          }
+          const int gray = computeGray(edgeColor, t);
+          renderer.drawPixelGray(screenX, screenY, quantizeNoiseDither(gray, screenX, screenY));
+        }
+      }
+    }
+
+    // Bottom letterbox
+    if (data.letterboxB > 0) {
+      const int imgBottomY = renderer.getScreenHeight() - data.letterboxB;
+      for (int screenY = imgBottomY; screenY < renderer.getScreenHeight(); screenY++) {
+        const float t = static_cast<float>(screenY - imgBottomY + 1) / static_cast<float>(data.letterboxB);
+        for (int screenX = 0; screenX < renderer.getScreenWidth(); screenX++) {
+          int edgeColor;
+          if (isSolid) {
+            edgeColor = solidColorB;
+          } else {
+            int srcCol = static_cast<int>(screenX / scale);
+            srcCol = std::max(0, std::min(srcCol, data.edgeCount - 1));
+            edgeColor = data.edgeB[srcCol];
+          }
+          const int gray = computeGray(edgeColor, t);
+          renderer.drawPixelGray(screenX, screenY, quantizeNoiseDither(gray, screenX, screenY));
+        }
+      }
+    }
+  } else {
+    // Left letterbox
+    if (data.letterboxA > 0) {
+      const int imgLeftX = data.letterboxA;
+      for (int screenX = 0; screenX < imgLeftX; screenX++) {
+        const float t = static_cast<float>(imgLeftX - screenX) / static_cast<float>(imgLeftX);
+        for (int screenY = 0; screenY < renderer.getScreenHeight(); screenY++) {
+          int edgeColor;
+          if (isSolid) {
+            edgeColor = solidColorA;
+          } else {
+            int srcRow = static_cast<int>(screenY / scale);
+            srcRow = std::max(0, std::min(srcRow, data.edgeCount - 1));
+            edgeColor = data.edgeA[srcRow];
+          }
+          const int gray = computeGray(edgeColor, t);
+          renderer.drawPixelGray(screenX, screenY, quantizeNoiseDither(gray, screenX, screenY));
+        }
+      }
+    }
+
+    // Right letterbox
+    if (data.letterboxB > 0) {
+      const int imgRightX = renderer.getScreenWidth() - data.letterboxB;
+      for (int screenX = imgRightX; screenX < renderer.getScreenWidth(); screenX++) {
+        const float t = static_cast<float>(screenX - imgRightX + 1) / static_cast<float>(data.letterboxB);
+        for (int screenY = 0; screenY < renderer.getScreenHeight(); screenY++) {
+          int edgeColor;
+          if (isSolid) {
+            edgeColor = solidColorB;
+          } else {
+            int srcRow = static_cast<int>(screenY / scale);
+            srcRow = std::max(0, std::min(srcRow, data.edgeCount - 1));
+            edgeColor = data.edgeB[srcRow];
+          }
+          const int gray = computeGray(edgeColor, t);
+          renderer.drawPixelGray(screenX, screenY, quantizeNoiseDither(gray, screenX, screenY));
+        }
+      }
+    }
+  }
+}
+
+}  // namespace
+
 void SleepActivity::onEnter() {
   Activity::onEnter();
   GUI.drawPopup(renderer, "Entering Sleep...");
@@ -32,7 +394,7 @@ void SleepActivity::onEnter() {
 
 void SleepActivity::renderCustomSleepScreen() const {
   // Check if we have a /sleep directory
-  auto dir = SdMan.open("/sleep");
+  auto dir = Storage.open("/sleep");
   if (dir && dir.isDirectory()) {
     std::vector<std::string> files;
     char name[500];
@@ -75,7 +437,7 @@ void SleepActivity::renderCustomSleepScreen() const {
       APP_STATE.saveToFile();
       const auto filename = "/sleep/" + files[randomFileIndex];
       FsFile file;
-      if (SdMan.openFileForRead("SLP", filename, file)) {
+      if (Storage.openFileForRead("SLP", filename, file)) {
         Serial.printf("[%lu] [SLP] Randomly loading: /sleep/%s\n", millis(), files[randomFileIndex].c_str());
         delay(100);
         Bitmap bitmap(file, true);
@@ -92,7 +454,7 @@ void SleepActivity::renderCustomSleepScreen() const {
   // 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.
   FsFile file;
-  if (SdMan.openFileForRead("SLP", "/sleep.bmp", file)) {
+  if (Storage.openFileForRead("SLP", "/sleep.bmp", file)) {
     Bitmap bitmap(file, true);
     if (bitmap.parseHeaders() == BmpReaderError::Ok) {
       Serial.printf("[%lu] [SLP] Loading: /sleep.bmp\n", millis());
@@ -121,7 +483,7 @@ void SleepActivity::renderDefaultSleepScreen() const {
   renderer.displayBuffer(HalDisplay::HALF_REFRESH);
 }
 
-void SleepActivity::renderBitmapSleepScreen(const Bitmap& bitmap) const {
+void SleepActivity::renderBitmapSleepScreen(const Bitmap& bitmap, const std::string& edgeCachePath) const {
   int x, y;
   const auto pageWidth = renderer.getScreenWidth();
   const auto pageHeight = renderer.getScreenHeight();
@@ -129,14 +491,14 @@ void SleepActivity::renderBitmapSleepScreen(const Bitmap& bitmap) const {
 
   Serial.printf("[%lu] [SLP] bitmap %d x %d, screen %d x %d\n", millis(), bitmap.getWidth(), bitmap.getHeight(),
                 pageWidth, pageHeight);
-  if (bitmap.getWidth() > pageWidth || bitmap.getHeight() > pageHeight) {
+
-    // image will scale, make sure placement is right
+  // Always compute aspect-ratio-preserving scale and position (supports both larger and smaller images)
   float ratio = static_cast<float>(bitmap.getWidth()) / static_cast<float>(bitmap.getHeight());
   const float screenRatio = static_cast<float>(pageWidth) / static_cast<float>(pageHeight);
 
   Serial.printf("[%lu] [SLP] bitmap ratio: %f, screen ratio: %f\n", millis(), ratio, screenRatio);
   if (ratio > screenRatio) {
-      // image wider than viewport ratio, scaled down image needs to be centered vertically
+    // image wider than viewport ratio, needs to be centered vertically
     if (SETTINGS.sleepScreenCoverMode == CrossPointSettings::SLEEP_SCREEN_COVER_MODE::CROP) {
       cropX = 1.0f - (screenRatio / ratio);
       Serial.printf("[%lu] [SLP] Cropping bitmap x: %f\n", millis(), cropX);
@@ -146,7 +508,7 @@ void SleepActivity::renderBitmapSleepScreen(const Bitmap& bitmap) const {
     y = std::round((static_cast<float>(pageHeight) - static_cast<float>(pageWidth) / ratio) / 2);
     Serial.printf("[%lu] [SLP] Centering with ratio %f to y=%d\n", millis(), ratio, y);
   } else {
-      // image taller than viewport ratio, scaled down image needs to be centered horizontally
+    // image taller than or equal to viewport ratio, needs to be centered horizontally
     if (SETTINGS.sleepScreenCoverMode == CrossPointSettings::SLEEP_SCREEN_COVER_MODE::CROP) {
       cropY = 1.0f - (ratio / screenRatio);
       Serial.printf("[%lu] [SLP] Cropping bitmap y: %f\n", millis(), cropY);
@@ -156,18 +518,52 @@ void SleepActivity::renderBitmapSleepScreen(const Bitmap& bitmap) const {
     y = 0;
     Serial.printf("[%lu] [SLP] Centering with ratio %f to x=%d\n", millis(), ratio, x);
   }
-  } else {
-    // center the image
-    x = (pageWidth - bitmap.getWidth()) / 2;
-    y = (pageHeight - bitmap.getHeight()) / 2;
-  }
 
   Serial.printf("[%lu] [SLP] drawing to %d x %d\n", millis(), x, y);
+
+  // Compute the scale factor (same formula as drawBitmap) so we can map screen coords to source coords
+  const float effectiveWidth = (1.0f - cropX) * bitmap.getWidth();
+  const float effectiveHeight = (1.0f - cropY) * bitmap.getHeight();
+  const float scale =
+      std::min(static_cast<float>(pageWidth) / effectiveWidth, static_cast<float>(pageHeight) / effectiveHeight);
+
+  // Determine letterbox fill settings
+  const uint8_t fillMode = SETTINGS.sleepScreenLetterboxFill;
+  const bool wantFill = (fillMode != CrossPointSettings::SLEEP_SCREEN_LETTERBOX_FILL::LETTERBOX_NONE);
+  const int targetColor =
+      (SETTINGS.sleepScreenGradientDir == CrossPointSettings::SLEEP_SCREEN_GRADIENT_DIR::GRADIENT_TO_BLACK) ? 0 : 255;
+
+  static const char* fillModeNames[] = {"none", "solid", "blended", "gradient"};
+  const char* fillModeName = (fillMode < 4) ? fillModeNames[fillMode] : "unknown";
+
+  // Load cached edge data or sample from bitmap (first pass over bitmap, then rewind)
+  LetterboxGradientData gradientData;
+  const bool hasLetterbox = (x > 0 || y > 0);
+  if (hasLetterbox && wantFill) {
+    bool cacheLoaded = false;
+    if (!edgeCachePath.empty()) {
+      cacheLoaded = loadEdgeCache(edgeCachePath, pageWidth, pageHeight, gradientData);
+    }
+    if (!cacheLoaded) {
+      Serial.printf("[%lu] [SLP] Letterbox detected (x=%d, y=%d), sampling edges for %s fill\n", millis(), x, y,
+                    fillModeName);
+      gradientData = sampleBitmapEdges(bitmap, x, y, pageWidth, pageHeight, scale, cropX, cropY);
+      if (!edgeCachePath.empty() && gradientData.edgeA) {
+        saveEdgeCache(edgeCachePath, pageWidth, pageHeight, gradientData);
+      }
+    }
+  }
+
   renderer.clearScreen();
 
   const bool hasGreyscale = bitmap.hasGreyscale() &&
                             SETTINGS.sleepScreenCoverFilter == CrossPointSettings::SLEEP_SCREEN_COVER_FILTER::NO_FILTER;
 
+  // Draw letterbox fill (BW pass)
+  if (gradientData.edgeA) {
+    drawLetterboxFill(renderer, gradientData, scale, fillMode, targetColor);
+  }
+
   renderer.drawBitmap(bitmap, x, y, pageWidth, pageHeight, cropX, cropY);
 
   if (SETTINGS.sleepScreenCoverFilter == CrossPointSettings::SLEEP_SCREEN_COVER_FILTER::INVERTED_BLACK_AND_WHITE) {
@@ -180,18 +576,26 @@ void SleepActivity::renderBitmapSleepScreen(const Bitmap& bitmap) const {
     bitmap.rewindToData();
     renderer.clearScreen(0x00);
     renderer.setRenderMode(GfxRenderer::GRAYSCALE_LSB);
+    if (gradientData.edgeA) {
+      drawLetterboxFill(renderer, gradientData, scale, fillMode, targetColor);
+    }
     renderer.drawBitmap(bitmap, x, y, pageWidth, pageHeight, cropX, cropY);
     renderer.copyGrayscaleLsbBuffers();
 
     bitmap.rewindToData();
     renderer.clearScreen(0x00);
     renderer.setRenderMode(GfxRenderer::GRAYSCALE_MSB);
+    if (gradientData.edgeA) {
+      drawLetterboxFill(renderer, gradientData, scale, fillMode, targetColor);
+    }
     renderer.drawBitmap(bitmap, x, y, pageWidth, pageHeight, cropX, cropY);
     renderer.copyGrayscaleMsbBuffers();
 
     renderer.displayGrayBuffer();
     renderer.setRenderMode(GfxRenderer::BW);
   }
+
+  gradientData.free();
 }
 
 void SleepActivity::renderCoverSleepScreen() const {
@@ -261,12 +665,18 @@ void SleepActivity::renderCoverSleepScreen() const {
     return (this->*renderNoCoverSleepScreen)();
   }
 
+  // Derive edge cache path from cover BMP path (e.g. cover.bmp -> cover_edges.bin)
+  std::string edgeCachePath;
+  if (coverBmpPath.size() > 4) {
+    edgeCachePath = coverBmpPath.substr(0, coverBmpPath.size() - 4) + "_edges.bin";
+  }
+
   FsFile file;
-  if (SdMan.openFileForRead("SLP", coverBmpPath, file)) {
+  if (Storage.openFileForRead("SLP", coverBmpPath, file)) {
     Bitmap bitmap(file);
     if (bitmap.parseHeaders() == BmpReaderError::Ok) {
       Serial.printf("[SLP] Rendering sleep cover: %s\n", coverBmpPath.c_str());
-      renderBitmapSleepScreen(bitmap);
+      renderBitmapSleepScreen(bitmap, edgeCachePath);
       return;
     }
   }

src/activities/boot_sleep/SleepActivity.h

@@ -1,4 +1,6 @@
 #pragma once
+#include <string>
+
 #include "../Activity.h"
 
 class Bitmap;
@@ -13,6 +15,6 @@ class SleepActivity final : public Activity {
   void renderDefaultSleepScreen() const;
   void renderCustomSleepScreen() const;
   void renderCoverSleepScreen() const;
-  void renderBitmapSleepScreen(const Bitmap& bitmap) const;
+  void renderBitmapSleepScreen(const Bitmap& bitmap, const std::string& edgeCachePath = "") const;
   void renderBlankSleepScreen() const;
 };

src/activities/home/HomeActivity.cpp

@@ -3,7 +3,7 @@
 #include <Bitmap.h>
 #include <Epub.h>
 #include <GfxRenderer.h>
-#include <SDCardManager.h>
+#include <HalStorage.h>
 #include <Utf8.h>
 #include <Xtc.h>
 
@@ -47,7 +47,7 @@ void HomeActivity::loadRecentBooks(int maxBooks) {
     }
 
     // Skip if file no longer exists
-    if (!SdMan.exists(book.path.c_str())) {
+    if (!Storage.exists(book.path.c_str())) {
       continue;
     }
 
@@ -64,7 +64,7 @@ void HomeActivity::loadRecentCovers(int coverHeight) {
   for (RecentBook& book : recentBooks) {
     if (!book.coverBmpPath.empty()) {
       std::string coverPath = UITheme::getCoverThumbPath(book.coverBmpPath, coverHeight);
-      if (!SdMan.exists(coverPath.c_str())) {
+      if (!Storage.exists(coverPath.c_str())) {
         // If epub, try to load the metadata for title/author and cover
         if (StringUtils::checkFileExtension(book.path, ".epub")) {
           Epub epub(book.path, "/.crosspoint");

src/activities/home/MyLibraryActivity.cpp

@@ -1,7 +1,7 @@
 #include "MyLibraryActivity.h"
 
 #include <GfxRenderer.h>
-#include <SDCardManager.h>
+#include <HalStorage.h>
 
 #include <algorithm>
 
@@ -33,7 +33,7 @@ void MyLibraryActivity::taskTrampoline(void* param) {
 void MyLibraryActivity::loadFiles() {
   files.clear();
 
-  auto root = SdMan.open(basepath.c_str());
+  auto root = Storage.open(basepath.c_str());
   if (!root || !root.isDirectory()) {
     if (root) root.close();
     return;

src/activities/home/RecentBooksActivity.cpp

@@ -1,7 +1,7 @@
 #include "RecentBooksActivity.h"
 
 #include <GfxRenderer.h>
-#include <SDCardManager.h>
+#include <HalStorage.h>
 
 #include <algorithm>
 
@@ -28,7 +28,7 @@ void RecentBooksActivity::loadRecentBooks() {
 
   for (const auto& book : books) {
     // Skip if file no longer exists
-    if (!SdMan.exists(book.path.c_str())) {
+    if (!Storage.exists(book.path.c_str())) {
       continue;
     }
     recentBooks.push_back(book);

src/activities/reader/EpubReaderActivity.cpp

@@ -3,7 +3,7 @@
 #include <Epub/Page.h>
 #include <FsHelpers.h>
 #include <GfxRenderer.h>
-#include <SDCardManager.h>
+#include <HalStorage.h>
 
 #include "CrossPointSettings.h"
 #include "CrossPointState.h"
@@ -77,7 +77,7 @@ void EpubReaderActivity::onEnter() {
   epub->setupCacheDir();
 
   FsFile f;
-  if (SdMan.openFileForRead("ERS", epub->getCachePath() + "/progress.bin", f)) {
+  if (Storage.openFileForRead("ERS", epub->getCachePath() + "/progress.bin", f)) {
     uint8_t data[6];
     int dataSize = f.read(data, 6);
     if (dataSize == 4 || dataSize == 6) {
@@ -204,15 +204,15 @@ void EpubReaderActivity::loop() {
     xSemaphoreGive(renderingMutex);
   }
 
-  // Long press BACK (1s+) goes directly to home
+  // Long press BACK (1s+) goes to file selection
   if (mappedInput.isPressed(MappedInputManager::Button::Back) && mappedInput.getHeldTime() >= goHomeMs) {
-    onGoHome();
+    onGoBack();
     return;
   }
 
-  // Short press BACK goes to file selection
+  // Short press BACK goes directly to home
   if (mappedInput.wasReleased(MappedInputManager::Button::Back) && mappedInput.getHeldTime() < goHomeMs) {
-    onGoBack();
+    onGoHome();
     return;
   }
 
@@ -654,7 +654,7 @@ void EpubReaderActivity::renderScreen() {
 
 void EpubReaderActivity::saveProgress(int spineIndex, int currentPage, int pageCount) {
   FsFile f;
-  if (SdMan.openFileForWrite("ERS", epub->getCachePath() + "/progress.bin", f)) {
+  if (Storage.openFileForWrite("ERS", epub->getCachePath() + "/progress.bin", f)) {
     uint8_t data[6];
     data[0] = currentSpineIndex & 0xFF;
     data[1] = (currentSpineIndex >> 8) & 0xFF;

src/activities/reader/KOReaderSyncActivity.cpp

@@ -317,7 +317,6 @@ void KOReaderSyncActivity::render() {
              localProgress.percentage * 100);
     renderer.drawText(UI_10_FONT_ID, 20, 320, localPageStr);
 
-    // Options
     const int optionY = 350;
     const int optionHeight = 30;
 
@@ -333,13 +332,8 @@ void KOReaderSyncActivity::render() {
     }
     renderer.drawText(UI_10_FONT_ID, 20, optionY + optionHeight, "Upload local progress", selectedOption != 1);
 
-    // Cancel option
+    // Bottom button hints: show Back and Select
-    if (selectedOption == 2) {
+    const auto labels = mappedInput.mapLabels("Back", "Select", "", "");
-      renderer.fillRect(0, optionY + optionHeight * 2 - 2, pageWidth - 1, optionHeight);
-    }
-    renderer.drawText(UI_10_FONT_ID, 20, optionY + optionHeight * 2, "Cancel", selectedOption != 2);
-
-    const auto labels = mappedInput.mapLabels("", "Select", "", "");
     GUI.drawButtonHints(renderer, labels.btn1, labels.btn2, labels.btn3, labels.btn4);
     renderer.displayBuffer();
     return;
@@ -349,7 +343,7 @@ void KOReaderSyncActivity::render() {
     renderer.drawCenteredText(UI_10_FONT_ID, 280, "No remote progress found", true, EpdFontFamily::BOLD);
     renderer.drawCenteredText(UI_10_FONT_ID, 320, "Upload current position?");
 
-    const auto labels = mappedInput.mapLabels("Cancel", "Upload", "", "");
+    const auto labels = mappedInput.mapLabels("Back", "Upload", "", "");
     GUI.drawButtonHints(renderer, labels.btn1, labels.btn2, labels.btn3, labels.btn4);
     renderer.displayBuffer();
     return;
@@ -392,11 +386,11 @@ void KOReaderSyncActivity::loop() {
     // Navigate options
     if (mappedInput.wasPressed(MappedInputManager::Button::Up) ||
         mappedInput.wasPressed(MappedInputManager::Button::Left)) {
-      selectedOption = (selectedOption + 2) % 3;  // Wrap around
+      selectedOption = (selectedOption + 1) % 2;  // Wrap around among 2 options
       updateRequired = true;
     } else if (mappedInput.wasPressed(MappedInputManager::Button::Down) ||
                mappedInput.wasPressed(MappedInputManager::Button::Right)) {
-      selectedOption = (selectedOption + 1) % 3;
+      selectedOption = (selectedOption + 1) % 2;  // Wrap around among 2 options
       updateRequired = true;
     }
 
@@ -407,9 +401,6 @@ void KOReaderSyncActivity::loop() {
       } else if (selectedOption == 1) {
         // Upload local progress
         performUpload();
-      } else {
-        // Cancel
-        onCancel();
       }
     }
 

src/activities/reader/KOReaderSyncActivity.h

@@ -18,7 +18,7 @@
  * 1. Connect to WiFi (if not connected)
  * 2. Calculate document hash
  * 3. Fetch remote progress
- * 4. Show comparison and options (Apply/Upload/Cancel)
+ * 4. Show comparison and options (Apply/Upload)
  * 5. Apply or upload progress
  */
 class KOReaderSyncActivity final : public ActivityWithSubactivity {
@@ -82,7 +82,7 @@ class KOReaderSyncActivity final : public ActivityWithSubactivity {
   // Local progress as KOReader format (for display)
   KOReaderPosition localProgress;
 
-  // Selection in result screen (0=Apply, 1=Upload, 2=Cancel)
+  // Selection in result screen (0=Apply, 1=Upload)
   int selectedOption = 0;
 
   OnCancelCallback onCancel;

src/activities/reader/ReaderActivity.cpp

@@ -1,5 +1,7 @@
 #include "ReaderActivity.h"
 
+#include <HalStorage.h>
+
 #include "Epub.h"
 #include "EpubReaderActivity.h"
 #include "Txt.h"
@@ -27,7 +29,7 @@ bool ReaderActivity::isTxtFile(const std::string& path) {
 }
 
 std::unique_ptr<Epub> ReaderActivity::loadEpub(const std::string& path) {
-  if (!SdMan.exists(path.c_str())) {
+  if (!Storage.exists(path.c_str())) {
     Serial.printf("[%lu] [   ] File does not exist: %s\n", millis(), path.c_str());
     return nullptr;
   }
@@ -42,7 +44,7 @@ std::unique_ptr<Epub> ReaderActivity::loadEpub(const std::string& path) {
 }
 
 std::unique_ptr<Xtc> ReaderActivity::loadXtc(const std::string& path) {
-  if (!SdMan.exists(path.c_str())) {
+  if (!Storage.exists(path.c_str())) {
     Serial.printf("[%lu] [   ] File does not exist: %s\n", millis(), path.c_str());
     return nullptr;
   }
@@ -57,7 +59,7 @@ std::unique_ptr<Xtc> ReaderActivity::loadXtc(const std::string& path) {
 }
 
 std::unique_ptr<Txt> ReaderActivity::loadTxt(const std::string& path) {
-  if (!SdMan.exists(path.c_str())) {
+  if (!Storage.exists(path.c_str())) {
     Serial.printf("[%lu] [   ] File does not exist: %s\n", millis(), path.c_str());
     return nullptr;
   }

src/activities/reader/TxtReaderActivity.cpp

@@ -1,7 +1,7 @@
 #include "TxtReaderActivity.h"
 
 #include <GfxRenderer.h>
-#include <SDCardManager.h>
+#include <HalStorage.h>
 #include <Serialization.h>
 #include <Utf8.h>
 
@@ -102,15 +102,15 @@ void TxtReaderActivity::loop() {
     return;
   }
 
-  // Long press BACK (1s+) goes directly to home
+  // Long press BACK (1s+) goes to file selection
   if (mappedInput.isPressed(MappedInputManager::Button::Back) && mappedInput.getHeldTime() >= goHomeMs) {
-    onGoHome();
+    onGoBack();
     return;
   }
 
-  // Short press BACK goes to file selection
+  // Short press BACK goes directly to home
   if (mappedInput.wasReleased(MappedInputManager::Button::Back) && mappedInput.getHeldTime() < goHomeMs) {
-    onGoBack();
+    onGoHome();
     return;
   }
 
@@ -565,7 +565,7 @@ void TxtReaderActivity::renderStatusBar(const int orientedMarginRight, const int
 
 void TxtReaderActivity::saveProgress() const {
   FsFile f;
-  if (SdMan.openFileForWrite("TRS", txt->getCachePath() + "/progress.bin", f)) {
+  if (Storage.openFileForWrite("TRS", txt->getCachePath() + "/progress.bin", f)) {
     uint8_t data[4];
     data[0] = currentPage & 0xFF;
     data[1] = (currentPage >> 8) & 0xFF;
@@ -578,7 +578,7 @@ void TxtReaderActivity::saveProgress() const {
 
 void TxtReaderActivity::loadProgress() {
   FsFile f;
-  if (SdMan.openFileForRead("TRS", txt->getCachePath() + "/progress.bin", f)) {
+  if (Storage.openFileForRead("TRS", txt->getCachePath() + "/progress.bin", f)) {
     uint8_t data[4];
     if (f.read(data, 4) == 4) {
       currentPage = data[0] + (data[1] << 8);
@@ -609,7 +609,7 @@ bool TxtReaderActivity::loadPageIndexCache() {
 
   std::string cachePath = txt->getCachePath() + "/index.bin";
   FsFile f;
-  if (!SdMan.openFileForRead("TRS", cachePath, f)) {
+  if (!Storage.openFileForRead("TRS", cachePath, f)) {
     Serial.printf("[%lu] [TRS] No page index cache found\n", millis());
     return false;
   }
@@ -701,7 +701,7 @@ bool TxtReaderActivity::loadPageIndexCache() {
 void TxtReaderActivity::savePageIndexCache() const {
   std::string cachePath = txt->getCachePath() + "/index.bin";
   FsFile f;
-  if (!SdMan.openFileForWrite("TRS", cachePath, f)) {
+  if (!Storage.openFileForWrite("TRS", cachePath, f)) {
     Serial.printf("[%lu] [TRS] Failed to save page index cache\n", millis());
     return;
   }

src/activities/reader/XtcReaderActivity.cpp

@@ -9,7 +9,7 @@
 
 #include <FsHelpers.h>
 #include <GfxRenderer.h>
-#include <SDCardManager.h>
+#include <HalStorage.h>
 
 #include "CrossPointSettings.h"
 #include "CrossPointState.h"
@@ -102,15 +102,15 @@ void XtcReaderActivity::loop() {
     }
   }
 
-  // Long press BACK (1s+) goes directly to home
+  // Long press BACK (1s+) goes to file selection
   if (mappedInput.isPressed(MappedInputManager::Button::Back) && mappedInput.getHeldTime() >= goHomeMs) {
-    onGoHome();
+    onGoBack();
     return;
   }
 
-  // Short press BACK goes to file selection
+  // Short press BACK goes directly to home
   if (mappedInput.wasReleased(MappedInputManager::Button::Back) && mappedInput.getHeldTime() < goHomeMs) {
-    onGoBack();
+    onGoHome();
     return;
   }
 
@@ -372,7 +372,7 @@ void XtcReaderActivity::renderPage() {
 
 void XtcReaderActivity::saveProgress() const {
   FsFile f;
-  if (SdMan.openFileForWrite("XTR", xtc->getCachePath() + "/progress.bin", f)) {
+  if (Storage.openFileForWrite("XTR", xtc->getCachePath() + "/progress.bin", f)) {
     uint8_t data[4];
     data[0] = currentPage & 0xFF;
     data[1] = (currentPage >> 8) & 0xFF;
@@ -385,7 +385,7 @@ void XtcReaderActivity::saveProgress() const {
 
 void XtcReaderActivity::loadProgress() {
   FsFile f;
-  if (SdMan.openFileForRead("XTR", xtc->getCachePath() + "/progress.bin", f)) {
+  if (Storage.openFileForRead("XTR", xtc->getCachePath() + "/progress.bin", f)) {
     uint8_t data[4];
     if (f.read(data, 4) == 4) {
       currentPage = data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);

src/activities/settings/ClearCacheActivity.cpp

@@ -1,8 +1,8 @@
 #include "ClearCacheActivity.h"
 
 #include <GfxRenderer.h>
+#include <HalStorage.h>
 #include <HardwareSerial.h>
-#include <SDCardManager.h>
 
 #include "MappedInputManager.h"
 #include "components/UITheme.h"
@@ -107,7 +107,7 @@ void ClearCacheActivity::clearCache() {
   Serial.printf("[%lu] [CLEAR_CACHE] Clearing cache...\n", millis());
 
   // Open .crosspoint directory
-  auto root = SdMan.open("/.crosspoint");
+  auto root = Storage.open("/.crosspoint");
   if (!root || !root.isDirectory()) {
     Serial.printf("[%lu] [CLEAR_CACHE] Failed to open cache directory\n", millis());
     if (root) root.close();
@@ -132,7 +132,7 @@ void ClearCacheActivity::clearCache() {
 
       file.close();  // Close before attempting to delete
 
-      if (SdMan.removeDir(fullPath.c_str())) {
+      if (Storage.removeDir(fullPath.c_str())) {
         clearedCount++;
       } else {
         Serial.printf("[%lu] [CLEAR_CACHE] Failed to remove: %s\n", millis(), fullPath.c_str());

src/activities/settings/SettingsActivity.cpp

@@ -10,6 +10,7 @@
 #include "KOReaderSettingsActivity.h"
 #include "MappedInputManager.h"
 #include "OtaUpdateActivity.h"
+#include "SettingsList.h"
 #include "components/UITheme.h"
 #include "fontIds.h"
 
@@ -17,54 +18,6 @@ const char* SettingsActivity::categoryNames[categoryCount] = {"Display", "Reader
 
 namespace {
 constexpr int changeTabsMs = 700;
-constexpr int displaySettingsCount = 8;
-const SettingInfo displaySettings[displaySettingsCount] = {
-    // Should match with SLEEP_SCREEN_MODE
-    SettingInfo::Enum("Sleep Screen", &CrossPointSettings::sleepScreen,
-                      {"Dark", "Light", "Custom", "Cover", "None", "Cover + Custom"}),
-    SettingInfo::Enum("Sleep Screen Cover Mode", &CrossPointSettings::sleepScreenCoverMode, {"Fit", "Crop"}),
-    SettingInfo::Enum("Sleep Screen Cover Filter", &CrossPointSettings::sleepScreenCoverFilter,
-                      {"None", "Contrast", "Inverted"}),
-    SettingInfo::Enum(
-        "Status Bar", &CrossPointSettings::statusBar,
-        {"None", "No Progress", "Full w/ Percentage", "Full w/ Book Bar", "Book Bar Only", "Full w/ Chapter Bar"}),
-    SettingInfo::Enum("Hide Battery %", &CrossPointSettings::hideBatteryPercentage, {"Never", "In Reader", "Always"}),
-    SettingInfo::Enum("Refresh Frequency", &CrossPointSettings::refreshFrequency,
-                      {"1 page", "5 pages", "10 pages", "15 pages", "30 pages"}),
-    SettingInfo::Enum("UI Theme", &CrossPointSettings::uiTheme, {"Classic", "Lyra"}),
-    SettingInfo::Toggle("Sunlight Fading Fix", &CrossPointSettings::fadingFix),
-};
-
-constexpr int readerSettingsCount = 10;
-const SettingInfo readerSettings[readerSettingsCount] = {
-    SettingInfo::Enum("Font Family", &CrossPointSettings::fontFamily, {"Bookerly", "Noto Sans", "Open Dyslexic"}),
-    SettingInfo::Enum("Font Size", &CrossPointSettings::fontSize, {"Small", "Medium", "Large", "X Large"}),
-    SettingInfo::Enum("Line Spacing", &CrossPointSettings::lineSpacing, {"Tight", "Normal", "Wide"}),
-    SettingInfo::Value("Screen Margin", &CrossPointSettings::screenMargin, {5, 40, 5}),
-    SettingInfo::Enum("Paragraph Alignment", &CrossPointSettings::paragraphAlignment,
-                      {"Justify", "Left", "Center", "Right", "Book's Style"}),
-    SettingInfo::Toggle("Book's Embedded Style", &CrossPointSettings::embeddedStyle),
-    SettingInfo::Toggle("Hyphenation", &CrossPointSettings::hyphenationEnabled),
-    SettingInfo::Enum("Reading Orientation", &CrossPointSettings::orientation,
-                      {"Portrait", "Landscape CW", "Inverted", "Landscape CCW"}),
-    SettingInfo::Toggle("Extra Paragraph Spacing", &CrossPointSettings::extraParagraphSpacing),
-    SettingInfo::Toggle("Text Anti-Aliasing", &CrossPointSettings::textAntiAliasing)};
-
-constexpr int controlsSettingsCount = 4;
-const SettingInfo controlsSettings[controlsSettingsCount] = {
-    // Launches the remap wizard for front buttons.
-    SettingInfo::Action("Remap Front Buttons"),
-    SettingInfo::Enum("Side Button Layout (reader)", &CrossPointSettings::sideButtonLayout,
-                      {"Prev, Next", "Next, Prev"}),
-    SettingInfo::Toggle("Long-press Chapter Skip", &CrossPointSettings::longPressChapterSkip),
-    SettingInfo::Enum("Short Power Button Click", &CrossPointSettings::shortPwrBtn, {"Ignore", "Sleep", "Page Turn"})};
-
-constexpr int systemSettingsCount = 5;
-const SettingInfo systemSettings[systemSettingsCount] = {
-    SettingInfo::Enum("Time to Sleep", &CrossPointSettings::sleepTimeout,
-                      {"1 min", "5 min", "10 min", "15 min", "30 min"}),
-    SettingInfo::Action("KOReader Sync"), SettingInfo::Action("OPDS Browser"), SettingInfo::Action("Clear Cache"),
-    SettingInfo::Action("Check for updates")};
 }  // namespace
 
 void SettingsActivity::taskTrampoline(void* param) {
@@ -76,13 +29,40 @@ void SettingsActivity::onEnter() {
   Activity::onEnter();
   renderingMutex = xSemaphoreCreateMutex();
 
+  // Build per-category vectors from the shared settings list
+  displaySettings.clear();
+  readerSettings.clear();
+  controlsSettings.clear();
+  systemSettings.clear();
+
+  for (auto& setting : getSettingsList()) {
+    if (!setting.category) continue;
+    if (strcmp(setting.category, "Display") == 0) {
+      displaySettings.push_back(std::move(setting));
+    } else if (strcmp(setting.category, "Reader") == 0) {
+      readerSettings.push_back(std::move(setting));
+    } else if (strcmp(setting.category, "Controls") == 0) {
+      controlsSettings.push_back(std::move(setting));
+    } else if (strcmp(setting.category, "System") == 0) {
+      systemSettings.push_back(std::move(setting));
+    }
+    // Web-only categories (KOReader Sync, OPDS Browser) are skipped for device UI
+  }
+
+  // Append device-only ACTION items
+  controlsSettings.insert(controlsSettings.begin(), SettingInfo::Action("Remap Front Buttons"));
+  systemSettings.push_back(SettingInfo::Action("KOReader Sync"));
+  systemSettings.push_back(SettingInfo::Action("OPDS Browser"));
+  systemSettings.push_back(SettingInfo::Action("Clear Cache"));
+  systemSettings.push_back(SettingInfo::Action("Check for updates"));
+
   // Reset selection to first category
   selectedCategoryIndex = 0;
   selectedSettingIndex = 0;
 
   // Initialize with first category (Display)
-  settingsList = displaySettings;
+  currentSettings = &displaySettings;
-  settingsCount = displaySettingsCount;
+  settingsCount = static_cast<int>(displaySettings.size());
 
   // Trigger first update
   updateRequired = true;
@@ -162,23 +142,20 @@ void SettingsActivity::loop() {
   if (hasChangedCategory) {
     selectedSettingIndex = (selectedSettingIndex == 0) ? 0 : 1;
     switch (selectedCategoryIndex) {
-      case 0:  // Display
+      case 0:
-        settingsList = displaySettings;
+        currentSettings = &displaySettings;
-        settingsCount = displaySettingsCount;
         break;
-      case 1:  // Reader
+      case 1:
-        settingsList = readerSettings;
+        currentSettings = &readerSettings;
-        settingsCount = readerSettingsCount;
         break;
-      case 2:  // Controls
+      case 2:
-        settingsList = controlsSettings;
+        currentSettings = &controlsSettings;
-        settingsCount = controlsSettingsCount;
         break;
-      case 3:  // System
+      case 3:
-        settingsList = systemSettings;
+        currentSettings = &systemSettings;
-        settingsCount = systemSettingsCount;
         break;
     }
+    settingsCount = static_cast<int>(currentSettings->size());
   }
 }
 
@@ -188,7 +165,7 @@ void SettingsActivity::toggleCurrentSetting() {
     return;
   }
 
-  const auto& setting = settingsList[selectedSetting];
+  const auto& setting = (*currentSettings)[selectedSetting];
 
   if (setting.type == SettingType::TOGGLE && setting.valuePtr != nullptr) {
     // Toggle the boolean value using the member pointer
@@ -283,24 +260,24 @@ void SettingsActivity::render() const {
   GUI.drawTabBar(renderer, Rect{0, metrics.topPadding + metrics.headerHeight, pageWidth, metrics.tabBarHeight}, tabs,
                  selectedSettingIndex == 0);
 
+  const auto& settings = *currentSettings;
   GUI.drawList(
       renderer,
       Rect{0, metrics.topPadding + metrics.headerHeight + metrics.tabBarHeight + metrics.verticalSpacing, pageWidth,
            pageHeight - (metrics.topPadding + metrics.headerHeight + metrics.tabBarHeight + metrics.buttonHintsHeight +
                          metrics.verticalSpacing * 2)},
-      settingsCount, selectedSettingIndex - 1, [this](int index) { return std::string(settingsList[index].name); },
+      settingsCount, selectedSettingIndex - 1, [&settings](int index) { return std::string(settings[index].name); },
       nullptr, nullptr,
-      [this](int i) {
+      [&settings](int i) {
-        const auto& setting = settingsList[i];
         std::string valueText = "";
-        if (settingsList[i].type == SettingType::TOGGLE && settingsList[i].valuePtr != nullptr) {
+        if (settings[i].type == SettingType::TOGGLE && settings[i].valuePtr != nullptr) {
-          const bool value = SETTINGS.*(settingsList[i].valuePtr);
+          const bool value = SETTINGS.*(settings[i].valuePtr);
           valueText = value ? "ON" : "OFF";
-        } else if (settingsList[i].type == SettingType::ENUM && settingsList[i].valuePtr != nullptr) {
+        } else if (settings[i].type == SettingType::ENUM && settings[i].valuePtr != nullptr) {
-          const uint8_t value = SETTINGS.*(settingsList[i].valuePtr);
+          const uint8_t value = SETTINGS.*(settings[i].valuePtr);
-          valueText = settingsList[i].enumValues[value];
+          valueText = settings[i].enumValues[value];
-        } else if (settingsList[i].type == SettingType::VALUE && settingsList[i].valuePtr != nullptr) {
+        } else if (settings[i].type == SettingType::VALUE && settings[i].valuePtr != nullptr) {
-          valueText = std::to_string(SETTINGS.*(settingsList[i].valuePtr));
+          valueText = std::to_string(SETTINGS.*(settings[i].valuePtr));
         }
         return valueText;
       });

src/activities/settings/SettingsActivity.h

@@ -11,12 +11,12 @@
 
 class CrossPointSettings;
 
-enum class SettingType { TOGGLE, ENUM, ACTION, VALUE };
+enum class SettingType { TOGGLE, ENUM, ACTION, VALUE, STRING };
 
 struct SettingInfo {
   const char* name;
   SettingType type;
-  uint8_t CrossPointSettings::* valuePtr;
+  uint8_t CrossPointSettings::* valuePtr = nullptr;
   std::vector<std::string> enumValues;
 
   struct ValueRange {
@@ -24,20 +24,100 @@ struct SettingInfo {
     uint8_t max;
     uint8_t step;
   };
-  ValueRange valueRange;
+  ValueRange valueRange = {};
 
-  static SettingInfo Toggle(const char* name, uint8_t CrossPointSettings::* ptr) {
+  const char* key = nullptr;       // JSON API key (nullptr for ACTION types)
-    return {name, SettingType::TOGGLE, ptr};
+  const char* category = nullptr;  // Category for web UI grouping
+
+  // Direct char[] string fields (for settings stored in CrossPointSettings)
+  char* stringPtr = nullptr;
+  size_t stringMaxLen = 0;
+
+  // Dynamic accessors (for settings stored outside CrossPointSettings, e.g. KOReaderCredentialStore)
+  std::function<uint8_t()> valueGetter;
+  std::function<void(uint8_t)> valueSetter;
+  std::function<std::string()> stringGetter;
+  std::function<void(const std::string&)> stringSetter;
+
+  static SettingInfo Toggle(const char* name, uint8_t CrossPointSettings::* ptr, const char* key = nullptr,
+                            const char* category = nullptr) {
+    SettingInfo s;
+    s.name = name;
+    s.type = SettingType::TOGGLE;
+    s.valuePtr = ptr;
+    s.key = key;
+    s.category = category;
+    return s;
   }
 
-  static SettingInfo Enum(const char* name, uint8_t CrossPointSettings::* ptr, std::vector<std::string> values) {
+  static SettingInfo Enum(const char* name, uint8_t CrossPointSettings::* ptr, std::vector<std::string> values,
-    return {name, SettingType::ENUM, ptr, std::move(values)};
+                          const char* key = nullptr, const char* category = nullptr) {
+    SettingInfo s;
+    s.name = name;
+    s.type = SettingType::ENUM;
+    s.valuePtr = ptr;
+    s.enumValues = std::move(values);
+    s.key = key;
+    s.category = category;
+    return s;
   }
 
-  static SettingInfo Action(const char* name) { return {name, SettingType::ACTION, nullptr}; }
+  static SettingInfo Action(const char* name) {
+    SettingInfo s;
+    s.name = name;
+    s.type = SettingType::ACTION;
+    return s;
+  }
 
-  static SettingInfo Value(const char* name, uint8_t CrossPointSettings::* ptr, const ValueRange valueRange) {
+  static SettingInfo Value(const char* name, uint8_t CrossPointSettings::* ptr, const ValueRange valueRange,
-    return {name, SettingType::VALUE, ptr, {}, valueRange};
+                           const char* key = nullptr, const char* category = nullptr) {
+    SettingInfo s;
+    s.name = name;
+    s.type = SettingType::VALUE;
+    s.valuePtr = ptr;
+    s.valueRange = valueRange;
+    s.key = key;
+    s.category = category;
+    return s;
+  }
+
+  static SettingInfo String(const char* name, char* ptr, size_t maxLen, const char* key = nullptr,
+                            const char* category = nullptr) {
+    SettingInfo s;
+    s.name = name;
+    s.type = SettingType::STRING;
+    s.stringPtr = ptr;
+    s.stringMaxLen = maxLen;
+    s.key = key;
+    s.category = category;
+    return s;
+  }
+
+  static SettingInfo DynamicEnum(const char* name, std::vector<std::string> values, std::function<uint8_t()> getter,
+                                 std::function<void(uint8_t)> setter, const char* key = nullptr,
+                                 const char* category = nullptr) {
+    SettingInfo s;
+    s.name = name;
+    s.type = SettingType::ENUM;
+    s.enumValues = std::move(values);
+    s.valueGetter = std::move(getter);
+    s.valueSetter = std::move(setter);
+    s.key = key;
+    s.category = category;
+    return s;
+  }
+
+  static SettingInfo DynamicString(const char* name, std::function<std::string()> getter,
+                                   std::function<void(const std::string&)> setter, const char* key = nullptr,
+                                   const char* category = nullptr) {
+    SettingInfo s;
+    s.name = name;
+    s.type = SettingType::STRING;
+    s.stringGetter = std::move(getter);
+    s.stringSetter = std::move(setter);
+    s.key = key;
+    s.category = category;
+    return s;
   }
 };
 
@@ -48,7 +128,13 @@ class SettingsActivity final : public ActivityWithSubactivity {
   int selectedCategoryIndex = 0;  // Currently selected category
   int selectedSettingIndex = 0;
   int settingsCount = 0;
-  const SettingInfo* settingsList = nullptr;
+
+  // Per-category settings derived from shared list + device-only actions
+  std::vector<SettingInfo> displaySettings;
+  std::vector<SettingInfo> readerSettings;
+  std::vector<SettingInfo> controlsSettings;
+  std::vector<SettingInfo> systemSettings;
+  const std::vector<SettingInfo>* currentSettings = nullptr;
 
   const std::function<void()> onGoHome;
 

src/components/themes/BaseTheme.cpp

@@ -1,7 +1,7 @@
 #include "BaseTheme.h"
 
 #include <GfxRenderer.h>
-#include <SDCardManager.h>
+#include <HalStorage.h>
 #include <Utf8.h>
 
 #include <cstdint>
@@ -308,7 +308,7 @@ void BaseTheme::drawRecentBookCover(GfxRenderer& renderer, Rect rect, const std:
 
       // First time: load cover from SD and render
       FsFile file;
-      if (SdMan.openFileForRead("HOME", coverBmpPath, file)) {
+      if (Storage.openFileForRead("HOME", coverBmpPath, file)) {
         Bitmap bitmap(file);
         if (bitmap.parseHeaders() == BmpReaderError::Ok) {
           Serial.printf("Rendering bmp\n");

src/components/themes/lyra/LyraTheme.cpp

@@ -1,7 +1,7 @@
 #include "LyraTheme.h"
 
 #include <GfxRenderer.h>
-#include <SDCardManager.h>
+#include <HalStorage.h>
 
 #include <cstdint>
 #include <string>
@@ -283,7 +283,7 @@ void LyraTheme::drawRecentBookCover(GfxRenderer& renderer, Rect rect, const std:
 
           // First time: load cover from SD and render
           FsFile file;
-          if (SdMan.openFileForRead("HOME", coverBmpPath, file)) {
+          if (Storage.openFileForRead("HOME", coverBmpPath, file)) {
             Bitmap bitmap(file);
             if (bitmap.parseHeaders() == BmpReaderError::Ok) {
               float coverHeight = static_cast<float>(bitmap.getHeight());

src/main.cpp

@@ -3,7 +3,7 @@
 #include <GfxRenderer.h>
 #include <HalDisplay.h>
 #include <HalGPIO.h>
-#include <SDCardManager.h>
+#include <HalStorage.h>
 #include <SPI.h>
 #include <builtinFonts/all.h>
 
@@ -293,7 +293,7 @@ void setup() {
 
   // SD Card Initialization
   // We need 6 open files concurrently when parsing a new chapter
-  if (!SdMan.begin()) {
+  if (!Storage.begin()) {
     Serial.printf("[%lu] [   ] SD card initialization failed\n", millis());
     setupDisplayAndFonts();
     exitActivity();

src/network/CrossPointWebServer.cpp

@@ -3,14 +3,17 @@
 #include <ArduinoJson.h>
 #include <Epub.h>
 #include <FsHelpers.h>
-#include <SDCardManager.h>
+#include <HalStorage.h>
 #include <WiFi.h>
 #include <esp_task_wdt.h>
 
 #include <algorithm>
 
+#include "CrossPointSettings.h"
+#include "SettingsList.h"
 #include "html/FilesPageHtml.generated.h"
 #include "html/HomePageHtml.generated.h"
+#include "html/SettingsPageHtml.generated.h"
 #include "util/StringUtils.h"
 
 namespace {
@@ -148,6 +151,11 @@ void CrossPointWebServer::begin() {
   // Delete file/folder endpoint
   server->on("/delete", HTTP_POST, [this] { handleDelete(); });
 
+  // Settings endpoints
+  server->on("/settings", HTTP_GET, [this] { handleSettingsPage(); });
+  server->on("/api/settings", HTTP_GET, [this] { handleGetSettings(); });
+  server->on("/api/settings", HTTP_POST, [this] { handlePostSettings(); });
+
   server->onNotFound([this] { handleNotFound(); });
   Serial.printf("[%lu] [WEB] [MEM] Free heap after route setup: %d bytes\n", millis(), ESP.getFreeHeap());
 
@@ -316,7 +324,7 @@ void CrossPointWebServer::handleStatus() const {
 }
 
 void CrossPointWebServer::scanFiles(const char* path, const std::function<void(FileInfo)>& callback) const {
-  FsFile root = SdMan.open(path);
+  FsFile root = Storage.open(path);
   if (!root) {
     Serial.printf("[%lu] [WEB] Failed to open directory: %s\n", millis(), path);
     return;
@@ -458,12 +466,12 @@ void CrossPointWebServer::handleDownload() const {
     }
   }
 
-  if (!SdMan.exists(itemPath.c_str())) {
+  if (!Storage.exists(itemPath.c_str())) {
     server->send(404, "text/plain", "Item not found");
     return;
   }
 
-  FsFile file = SdMan.open(itemPath.c_str());
+  FsFile file = Storage.open(itemPath.c_str());
   if (!file) {
     server->send(500, "text/plain", "Failed to open file");
     return;
@@ -574,15 +582,15 @@ void CrossPointWebServer::handleUpload(UploadState& state) const {
 
     // Check if file already exists - SD operations can be slow
     esp_task_wdt_reset();
-    if (SdMan.exists(filePath.c_str())) {
+    if (Storage.exists(filePath.c_str())) {
       Serial.printf("[%lu] [WEB] [UPLOAD] Overwriting existing file: %s\n", millis(), filePath.c_str());
       esp_task_wdt_reset();
-      SdMan.remove(filePath.c_str());
+      Storage.remove(filePath.c_str());
     }
 
     // Open file for writing - this can be slow due to FAT cluster allocation
     esp_task_wdt_reset();
-    if (!SdMan.openFileForWrite("WEB", filePath, state.file)) {
+    if (!Storage.openFileForWrite("WEB", filePath, state.file)) {
       state.error = "Failed to create file on SD card";
       Serial.printf("[%lu] [WEB] [UPLOAD] FAILED to create file: %s\n", millis(), filePath.c_str());
       return;
@@ -660,7 +668,7 @@ void CrossPointWebServer::handleUpload(UploadState& state) const {
       String filePath = state.path;
       if (!filePath.endsWith("/")) filePath += "/";
       filePath += state.fileName;
-      SdMan.remove(filePath.c_str());
+      Storage.remove(filePath.c_str());
     }
     state.error = "Upload aborted";
     Serial.printf("[%lu] [WEB] Upload aborted\n", millis());
@@ -711,13 +719,13 @@ void CrossPointWebServer::handleCreateFolder() const {
   Serial.printf("[%lu] [WEB] Creating folder: %s\n", millis(), folderPath.c_str());
 
   // Check if already exists
-  if (SdMan.exists(folderPath.c_str())) {
+  if (Storage.exists(folderPath.c_str())) {
     server->send(400, "text/plain", "Folder already exists");
     return;
   }
 
   // Create the folder
-  if (SdMan.mkdir(folderPath.c_str())) {
+  if (Storage.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 {
@@ -763,12 +771,12 @@ void CrossPointWebServer::handleRename() const {
     return;
   }
 
-  if (!SdMan.exists(itemPath.c_str())) {
+  if (!Storage.exists(itemPath.c_str())) {
     server->send(404, "text/plain", "Item not found");
     return;
   }
 
-  FsFile file = SdMan.open(itemPath.c_str());
+  FsFile file = Storage.open(itemPath.c_str());
   if (!file) {
     server->send(500, "text/plain", "Failed to open file");
     return;
@@ -789,7 +797,7 @@ void CrossPointWebServer::handleRename() const {
   }
   newPath += newName;
 
-  if (SdMan.exists(newPath.c_str())) {
+  if (Storage.exists(newPath.c_str())) {
     file.close();
     server->send(409, "text/plain", "Target already exists");
     return;
@@ -839,12 +847,12 @@ void CrossPointWebServer::handleMove() const {
     }
   }
 
-  if (!SdMan.exists(itemPath.c_str())) {
+  if (!Storage.exists(itemPath.c_str())) {
     server->send(404, "text/plain", "Item not found");
     return;
   }
 
-  FsFile file = SdMan.open(itemPath.c_str());
+  FsFile file = Storage.open(itemPath.c_str());
   if (!file) {
     server->send(500, "text/plain", "Failed to open file");
     return;
@@ -855,12 +863,12 @@ void CrossPointWebServer::handleMove() const {
     return;
   }
 
-  if (!SdMan.exists(destPath.c_str())) {
+  if (!Storage.exists(destPath.c_str())) {
     file.close();
     server->send(404, "text/plain", "Destination not found");
     return;
   }
-  FsFile destDir = SdMan.open(destPath.c_str());
+  FsFile destDir = Storage.open(destPath.c_str());
   if (!destDir || !destDir.isDirectory()) {
     if (destDir) {
       destDir.close();
@@ -882,7 +890,7 @@ void CrossPointWebServer::handleMove() const {
     server->send(200, "text/plain", "Already in destination");
     return;
   }
-  if (SdMan.exists(newPath.c_str())) {
+  if (Storage.exists(newPath.c_str())) {
     file.close();
     server->send(409, "text/plain", "Target already exists");
     return;
@@ -942,7 +950,7 @@ void CrossPointWebServer::handleDelete() const {
   }
 
   // Check if item exists
-  if (!SdMan.exists(itemPath.c_str())) {
+  if (!Storage.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;
@@ -954,7 +962,7 @@ void CrossPointWebServer::handleDelete() const {
 
   if (itemType == "folder") {
     // For folders, try to remove (will fail if not empty)
-    FsFile dir = SdMan.open(itemPath.c_str());
+    FsFile dir = Storage.open(itemPath.c_str());
     if (dir && dir.isDirectory()) {
       // Check if folder is empty
       FsFile entry = dir.openNextFile();
@@ -968,10 +976,10 @@ void CrossPointWebServer::handleDelete() const {
       }
       dir.close();
     }
-    success = SdMan.rmdir(itemPath.c_str());
+    success = Storage.rmdir(itemPath.c_str());
   } else {
     // For files, use remove
-    success = SdMan.remove(itemPath.c_str());
+    success = Storage.remove(itemPath.c_str());
   }
 
   if (success) {
@@ -983,6 +991,168 @@ void CrossPointWebServer::handleDelete() const {
   }
 }
 
+void CrossPointWebServer::handleSettingsPage() const {
+  server->send(200, "text/html", SettingsPageHtml);
+  Serial.printf("[%lu] [WEB] Served settings page\n", millis());
+}
+
+void CrossPointWebServer::handleGetSettings() const {
+  auto settings = getSettingsList();
+
+  server->setContentLength(CONTENT_LENGTH_UNKNOWN);
+  server->send(200, "application/json", "");
+  server->sendContent("[");
+
+  char output[512];
+  constexpr size_t outputSize = sizeof(output);
+  bool seenFirst = false;
+  JsonDocument doc;
+
+  for (const auto& s : settings) {
+    if (!s.key) continue;  // Skip ACTION-only entries
+
+    doc.clear();
+    doc["key"] = s.key;
+    doc["name"] = s.name;
+    doc["category"] = s.category;
+
+    switch (s.type) {
+      case SettingType::TOGGLE: {
+        doc["type"] = "toggle";
+        if (s.valuePtr) {
+          doc["value"] = static_cast<int>(SETTINGS.*(s.valuePtr));
+        }
+        break;
+      }
+      case SettingType::ENUM: {
+        doc["type"] = "enum";
+        if (s.valuePtr) {
+          doc["value"] = static_cast<int>(SETTINGS.*(s.valuePtr));
+        } else if (s.valueGetter) {
+          doc["value"] = static_cast<int>(s.valueGetter());
+        }
+        JsonArray options = doc["options"].to<JsonArray>();
+        for (const auto& opt : s.enumValues) {
+          options.add(opt);
+        }
+        break;
+      }
+      case SettingType::VALUE: {
+        doc["type"] = "value";
+        if (s.valuePtr) {
+          doc["value"] = static_cast<int>(SETTINGS.*(s.valuePtr));
+        }
+        doc["min"] = s.valueRange.min;
+        doc["max"] = s.valueRange.max;
+        doc["step"] = s.valueRange.step;
+        break;
+      }
+      case SettingType::STRING: {
+        doc["type"] = "string";
+        if (s.stringGetter) {
+          doc["value"] = s.stringGetter();
+        } else if (s.stringPtr) {
+          doc["value"] = s.stringPtr;
+        }
+        break;
+      }
+      default:
+        continue;
+    }
+
+    const size_t written = serializeJson(doc, output, outputSize);
+    if (written >= outputSize) {
+      Serial.printf("[%lu] [WEB] Skipping oversized setting JSON for: %s\n", millis(), s.key);
+      continue;
+    }
+
+    if (seenFirst) {
+      server->sendContent(",");
+    } else {
+      seenFirst = true;
+    }
+    server->sendContent(output);
+  }
+
+  server->sendContent("]");
+  server->sendContent("");
+  Serial.printf("[%lu] [WEB] Served settings API\n", millis());
+}
+
+void CrossPointWebServer::handlePostSettings() {
+  if (!server->hasArg("plain")) {
+    server->send(400, "text/plain", "Missing JSON body");
+    return;
+  }
+
+  const String body = server->arg("plain");
+  JsonDocument doc;
+  const DeserializationError err = deserializeJson(doc, body);
+  if (err) {
+    server->send(400, "text/plain", String("Invalid JSON: ") + err.c_str());
+    return;
+  }
+
+  auto settings = getSettingsList();
+  int applied = 0;
+
+  for (auto& s : settings) {
+    if (!s.key) continue;
+    if (!doc[s.key].is<JsonVariant>()) continue;
+
+    switch (s.type) {
+      case SettingType::TOGGLE: {
+        const int val = doc[s.key].as<int>() ? 1 : 0;
+        if (s.valuePtr) {
+          SETTINGS.*(s.valuePtr) = val;
+        }
+        applied++;
+        break;
+      }
+      case SettingType::ENUM: {
+        const int val = doc[s.key].as<int>();
+        if (val >= 0 && val < static_cast<int>(s.enumValues.size())) {
+          if (s.valuePtr) {
+            SETTINGS.*(s.valuePtr) = static_cast<uint8_t>(val);
+          } else if (s.valueSetter) {
+            s.valueSetter(static_cast<uint8_t>(val));
+          }
+          applied++;
+        }
+        break;
+      }
+      case SettingType::VALUE: {
+        const int val = doc[s.key].as<int>();
+        if (val >= s.valueRange.min && val <= s.valueRange.max) {
+          if (s.valuePtr) {
+            SETTINGS.*(s.valuePtr) = static_cast<uint8_t>(val);
+          }
+          applied++;
+        }
+        break;
+      }
+      case SettingType::STRING: {
+        const std::string val = doc[s.key].as<std::string>();
+        if (s.stringSetter) {
+          s.stringSetter(val);
+        } else if (s.stringPtr && s.stringMaxLen > 0) {
+          strncpy(s.stringPtr, val.c_str(), s.stringMaxLen - 1);
+          s.stringPtr[s.stringMaxLen - 1] = '\0';
+        }
+        applied++;
+        break;
+      }
+      default:
+        break;
+    }
+  }
+
+  SETTINGS.saveToFile();
+
+  Serial.printf("[%lu] [WEB] Applied %d setting(s)\n", millis(), applied);
+  server->send(200, "text/plain", String("Applied ") + String(applied) + " setting(s)");
+}
+
 // WebSocket callback trampoline
 void CrossPointWebServer::wsEventCallback(uint8_t num, WStype_t type, uint8_t* payload, size_t length) {
   if (wsInstance) {
@@ -1007,7 +1177,7 @@ void CrossPointWebServer::onWebSocketEvent(uint8_t num, WStype_t type, uint8_t*
         String filePath = wsUploadPath;
         if (!filePath.endsWith("/")) filePath += "/";
         filePath += wsUploadFileName;
-        SdMan.remove(filePath.c_str());
+        Storage.remove(filePath.c_str());
         Serial.printf("[%lu] [WS] Deleted incomplete upload: %s\n", millis(), filePath.c_str());
       }
       wsUploadInProgress = false;
@@ -1051,13 +1221,13 @@ void CrossPointWebServer::onWebSocketEvent(uint8_t num, WStype_t type, uint8_t*
 
           // Check if file exists and remove it
           esp_task_wdt_reset();
-          if (SdMan.exists(filePath.c_str())) {
+          if (Storage.exists(filePath.c_str())) {
-            SdMan.remove(filePath.c_str());
+            Storage.remove(filePath.c_str());
           }
 
           // Open file for writing
           esp_task_wdt_reset();
-          if (!SdMan.openFileForWrite("WS", filePath, wsUploadFile)) {
+          if (!Storage.openFileForWrite("WS", filePath, wsUploadFile)) {
             wsServer->sendTXT(num, "ERROR:Failed to create file");
             wsUploadInProgress = false;
             return;

src/network/CrossPointWebServer.h

@@ -1,6 +1,6 @@
 #pragma once
 
-#include <SDCardManager.h>
+#include <HalStorage.h>
 #include <WebServer.h>
 #include <WebSocketsServer.h>
 #include <WiFiUdp.h>
@@ -100,4 +100,9 @@ class CrossPointWebServer {
   void handleRename() const;
   void handleMove() const;
   void handleDelete() const;
+
+  // Settings handlers
+  void handleSettingsPage() const;
+  void handleGetSettings() const;
+  void handlePostSettings();
 };

src/network/HttpDownloader.cpp

@@ -100,13 +100,13 @@ HttpDownloader::DownloadError HttpDownloader::downloadToFile(const std::string&
   Serial.printf("[%lu] [HTTP] Content-Length: %zu\n", millis(), contentLength);
 
   // Remove existing file if present
-  if (SdMan.exists(destPath.c_str())) {
+  if (Storage.exists(destPath.c_str())) {
-    SdMan.remove(destPath.c_str());
+    Storage.remove(destPath.c_str());
   }
 
   // Open file for writing
   FsFile file;
-  if (!SdMan.openFileForWrite("HTTP", destPath.c_str(), file)) {
+  if (!Storage.openFileForWrite("HTTP", destPath.c_str(), file)) {
     Serial.printf("[%lu] [HTTP] Failed to open file for writing\n", millis());
     http.end();
     return FILE_ERROR;
@@ -117,7 +117,7 @@ HttpDownloader::DownloadError HttpDownloader::downloadToFile(const std::string&
   if (!stream) {
     Serial.printf("[%lu] [HTTP] Failed to get stream\n", millis());
     file.close();
-    SdMan.remove(destPath.c_str());
+    Storage.remove(destPath.c_str());
     http.end();
     return HTTP_ERROR;
   }
@@ -145,7 +145,7 @@ HttpDownloader::DownloadError HttpDownloader::downloadToFile(const std::string&
     if (written != bytesRead) {
       Serial.printf("[%lu] [HTTP] Write failed: wrote %zu of %zu bytes\n", millis(), written, bytesRead);
       file.close();
-      SdMan.remove(destPath.c_str());
+      Storage.remove(destPath.c_str());
       http.end();
       return FILE_ERROR;
     }
@@ -165,7 +165,7 @@ HttpDownloader::DownloadError HttpDownloader::downloadToFile(const std::string&
   // Verify download size if known
   if (contentLength > 0 && downloaded != contentLength) {
     Serial.printf("[%lu] [HTTP] Size mismatch: got %zu, expected %zu\n", millis(), downloaded, contentLength);
-    SdMan.remove(destPath.c_str());
+    Storage.remove(destPath.c_str());
     return HTTP_ERROR;
   }
 

src/network/HttpDownloader.h

@@ -1,5 +1,5 @@
 #pragma once
-#include <SDCardManager.h>
+#include <HalStorage.h>
 
 #include <functional>
 #include <string>

src/network/html/FilesPage.html

@@ -628,6 +628,7 @@
 <div class="nav-links">
   <a href="/">Home</a>
   <a href="/files">File Manager</a>
+  <a href="/settings">Settings</a>
 </div>
 
 <div class="page-header">

src/network/html/HomePage.html

@@ -77,6 +77,7 @@
     <div class="nav-links">
       <a href="/">Home</a>
       <a href="/files">File Manager</a>
+      <a href="/settings">Settings</a>
     </div>
 
     <div class="card">

src/network/html/SettingsPage.html

@@ -0,0 +1,414 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <meta charset="UTF-8" />
+  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+  <title>CrossPoint Reader - Settings</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);
+    }
+    .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;
+    }
+    .setting-row {
+      display: flex;
+      justify-content: space-between;
+      align-items: center;
+      padding: 10px 0;
+      border-bottom: 1px solid #eee;
+    }
+    .setting-row:last-child {
+      border-bottom: none;
+    }
+    .setting-name {
+      font-weight: 500;
+      color: #2c3e50;
+      flex: 1;
+      min-width: 0;
+      padding-right: 12px;
+    }
+    .setting-control {
+      flex-shrink: 0;
+    }
+    .setting-control select,
+    .setting-control input[type="number"],
+    .setting-control input[type="text"],
+    .setting-control input[type="password"] {
+      padding: 6px 10px;
+      border: 1px solid #ddd;
+      border-radius: 4px;
+      font-size: 0.95em;
+      background: white;
+    }
+    .setting-control select {
+      min-width: 160px;
+    }
+    .setting-control input[type="text"],
+    .setting-control input[type="password"] {
+      width: 220px;
+    }
+    .setting-control input[type="number"] {
+      width: 80px;
+    }
+    /* Toggle switch */
+    .toggle-switch {
+      display: inline-block;
+      position: relative;
+      width: 48px;
+      height: 26px;
+    }
+    .toggle-switch input {
+      opacity: 0;
+      width: 0;
+      height: 0;
+    }
+    .toggle-slider {
+      position: absolute;
+      cursor: pointer;
+      top: 0; left: 0; right: 0; bottom: 0;
+      background-color: #ccc;
+      border-radius: 26px;
+      transition: 0.3s;
+    }
+    .toggle-slider:before {
+      position: absolute;
+      content: "";
+      height: 20px;
+      width: 20px;
+      left: 3px;
+      bottom: 3px;
+      background-color: white;
+      border-radius: 50%;
+      transition: 0.3s;
+    }
+    .toggle-switch input:checked + .toggle-slider {
+      background-color: #27ae60;
+    }
+    .toggle-switch input:checked + .toggle-slider:before {
+      transform: translateX(22px);
+    }
+    .save-container {
+      text-align: center;
+      margin: 20px 0;
+    }
+    .save-btn {
+      background-color: #27ae60;
+      color: white;
+      padding: 12px 40px;
+      border: none;
+      border-radius: 4px;
+      cursor: pointer;
+      font-size: 1.1em;
+      font-weight: 600;
+    }
+    .save-btn:hover {
+      background-color: #219a52;
+    }
+    .save-btn:disabled {
+      background-color: #95a5a6;
+      cursor: not-allowed;
+    }
+    .message {
+      padding: 12px;
+      border-radius: 4px;
+      margin: 15px 0;
+      text-align: center;
+      display: none;
+    }
+    .message.success {
+      background-color: #d4edda;
+      color: #155724;
+      border: 1px solid #c3e6cb;
+    }
+    .message.error {
+      background-color: #f8d7da;
+      color: #721c24;
+      border: 1px solid #f5c6cb;
+    }
+    .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); }
+    }
+    @media (max-width: 600px) {
+      body {
+        padding: 10px;
+        font-size: 14px;
+      }
+      .card {
+        padding: 12px;
+        margin: 10px 0;
+      }
+      h1 {
+        font-size: 1.3em;
+      }
+      .nav-links a {
+        padding: 8px 12px;
+        margin-right: 6px;
+        font-size: 0.9em;
+      }
+      .setting-row {
+        flex-wrap: wrap;
+        gap: 6px;
+      }
+      .setting-control select,
+      .setting-control input[type="text"],
+      .setting-control input[type="password"] {
+        min-width: 0;
+        width: 100%;
+      }
+    }
+  </style>
+</head>
+<body>
+  <h1>⚙️ Settings</h1>
+
+  <div class="nav-links">
+    <a href="/">Home</a>
+    <a href="/files">File Manager</a>
+    <a href="/settings">Settings</a>
+  </div>
+
+  <div id="message" class="message"></div>
+
+  <div id="settings-container">
+    <div class="loader-container">
+      <span class="loader"></span>
+    </div>
+  </div>
+
+  <div class="save-container" id="save-container" style="display:none;">
+    <button class="save-btn" id="saveBtn" onclick="saveSettings()">Save Settings</button>
+  </div>
+
+  <div class="card">
+    <p style="text-align: center; color: #95a5a6; margin: 0;">
+      CrossPoint E-Reader • Open Source
+    </p>
+  </div>
+
+<script>
+  let allSettings = [];
+  let originalValues = {};
+
+  function escapeHtml(unsafe) {
+    return unsafe
+      .replaceAll("&", "&amp;")
+      .replaceAll("<", "&lt;")
+      .replaceAll(">", "&gt;")
+      .replaceAll('"', "&quot;")
+      .replaceAll("'", "&#039;");
+  }
+
+  function showMessage(text, isError) {
+    const msg = document.getElementById('message');
+    msg.textContent = text;
+    msg.className = 'message ' + (isError ? 'error' : 'success');
+    msg.style.display = 'block';
+    setTimeout(function() { msg.style.display = 'none'; }, 4000);
+  }
+
+  function renderControl(setting) {
+    const id = 'setting-' + setting.key;
+
+    if (setting.type === 'toggle') {
+      const checked = setting.value ? 'checked' : '';
+      return '<label class="toggle-switch">' +
+        '<input type="checkbox" id="' + id + '" ' + checked + ' onchange="markChanged()">' +
+        '<span class="toggle-slider"></span></label>';
+    }
+
+    if (setting.type === 'enum') {
+      let html = '<select id="' + id + '" onchange="markChanged()">';
+      setting.options.forEach(function(opt, idx) {
+        const selected = idx === setting.value ? ' selected' : '';
+        html += '<option value="' + idx + '"' + selected + '>' + escapeHtml(opt) + '</option>';
+      });
+      html += '</select>';
+      return html;
+    }
+
+    if (setting.type === 'value') {
+      return '<input type="number" id="' + id + '" value="' + setting.value + '"' +
+        ' min="' + setting.min + '" max="' + setting.max + '" step="' + setting.step + '"' +
+        ' onchange="markChanged()">';
+    }
+
+    if (setting.type === 'string') {
+      const inputType = setting.name.toLowerCase().includes('password') ? 'password' : 'text';
+      const val = setting.value || '';
+      return '<input type="' + inputType + '" id="' + id + '" value="' + escapeHtml(val) + '"' +
+        ' oninput="markChanged()">';
+    }
+
+    return '';
+  }
+
+  function getValue(setting) {
+    const el = document.getElementById('setting-' + setting.key);
+    if (!el) return undefined;
+
+    if (setting.type === 'toggle') {
+      return el.checked ? 1 : 0;
+    }
+    if (setting.type === 'enum') {
+      return parseInt(el.value, 10);
+    }
+    if (setting.type === 'value') {
+      return parseInt(el.value, 10);
+    }
+    if (setting.type === 'string') {
+      return el.value;
+    }
+    return undefined;
+  }
+
+  function markChanged() {
+    document.getElementById('saveBtn').disabled = false;
+  }
+
+  async function loadSettings() {
+    try {
+      const response = await fetch('/api/settings');
+      if (!response.ok) {
+        throw new Error('Failed to load settings: ' + response.status);
+      }
+      allSettings = await response.json();
+
+      // Store original values
+      originalValues = {};
+      allSettings.forEach(function(s) {
+        originalValues[s.key] = s.value;
+      });
+
+      // Group by category
+      const groups = {};
+      allSettings.forEach(function(s) {
+        if (!groups[s.category]) groups[s.category] = [];
+        groups[s.category].push(s);
+      });
+
+      const container = document.getElementById('settings-container');
+      let html = '';
+
+      for (const category in groups) {
+        html += '<div class="card"><h2>' + escapeHtml(category) + '</h2>';
+        groups[category].forEach(function(s) {
+          html += '<div class="setting-row">' +
+            '<span class="setting-name">' + escapeHtml(s.name) + '</span>' +
+            '<span class="setting-control">' + renderControl(s) + '</span>' +
+            '</div>';
+        });
+        html += '</div>';
+      }
+
+      container.innerHTML = html;
+      document.getElementById('save-container').style.display = '';
+      document.getElementById('saveBtn').disabled = true;
+    } catch (e) {
+      console.error(e);
+      document.getElementById('settings-container').innerHTML =
+        '<div class="card"><p style="text-align:center;color:#e74c3c;">Failed to load settings</p></div>';
+    }
+  }
+
+  async function saveSettings() {
+    const btn = document.getElementById('saveBtn');
+    btn.disabled = true;
+    btn.textContent = 'Saving...';
+
+    // Collect only changed values
+    const changes = {};
+    allSettings.forEach(function(s) {
+      const current = getValue(s);
+      if (current !== undefined && current !== originalValues[s.key]) {
+        changes[s.key] = current;
+      }
+    });
+
+    if (Object.keys(changes).length === 0) {
+      showMessage('No changes to save.', false);
+      btn.textContent = 'Save Settings';
+      return;
+    }
+
+    try {
+      const response = await fetch('/api/settings', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify(changes)
+      });
+
+      if (!response.ok) {
+        const text = await response.text();
+        throw new Error(text || 'Save failed');
+      }
+
+      // Update original values to new values
+      for (const key in changes) {
+        originalValues[key] = changes[key];
+      }
+
+      showMessage('Settings saved successfully!', false);
+    } catch (e) {
+      console.error(e);
+      showMessage('Error: ' + e.message, true);
+    }
+
+    btn.textContent = 'Save Settings';
+  }
+
+  loadSettings();
+</script>
+</body>
+</html>