mod: Phase 3 — Re-port unmerged upstream PRs

Re-applied upstream PRs not yet merged to upstream/master: - #1055: Byte-level framebuffer writes (fillPhysicalHSpan*, optimized fillRect/drawLine/fillRectDither/fillPolygon) - #1027: Word-width cache (FNV-1a, 128-entry) and hyphenation early exit in ParsedText for 7-9% layout speedup - #1068: Already present in upstream — URL hyphenation fix - #1019: Already present in upstream — file extensions in browser - #1090/#1185/#1217: KOReader sync improvements — binary credential store, document hash caching, ChapterXPathIndexer integration - #1209: OPDS multi-server — OpdsBookBrowserActivity accepts OpdsServer, directory picker for downloads, download-complete prompt with open/back options - #857: Dictionary activities already ported in Phase 1/2 - #1003: Placeholder cover already integrated in Phase 2 Also fixed: STR_OFF i18n string, include paths, replaced Epub::isValidThumbnailBmp with Storage.exists, replaced StringUtils::checkFileExtension with FsHelpers equivalents. Made-with: Cursor
2026-03-07 16:15:42 -05:00
parent 30473c27d3
commit 60a3e21c0e
25 changed files with 811 additions and 295 deletions
--- a/lib/Epub/Epub/ParsedText.cpp
+++ b/lib/Epub/Epub/ParsedText.cpp
@@ -5,6 +5,7 @@

 #include <algorithm>
 #include <cmath>
+#include <cstring>
 #include <functional>
 #include <limits>
 #include <vector>
@@ -74,6 +75,80 @@ uint16_t measureWordWidth(const GfxRenderer& renderer, const int fontId, const s
  return renderer.getTextAdvanceX(fontId, sanitized.c_str(), style);
 }

+// ---------------------------------------------------------------------------
+// Direct-mapped word-width cache
+//
+// Avoids redundant getTextAdvanceX calls when the same (word, style, fontId)
+// triple appears across paragraphs.  A fixed-size static array is used so
+// that heap allocation and fragmentation are both zero.
+//
+// Eviction policy: hash-direct mapping — a word always occupies the single
+// slot determined by its hash; a collision simply overwrites that slot.
+// This gives O(1) lookup (one hash + one memcmp) regardless of how full the
+// cache is, avoiding the O(n) linear-scan overhead that causes a regression
+// on corpora with many unique words (e.g. German compound-heavy text).
+//
+// Words longer than 23 bytes bypass the cache entirely — they are uncommon,
+// unlikely to repeat verbatim, and exceed the fixed-width key buffer.
+// ---------------------------------------------------------------------------
+
+struct WordWidthCacheEntry {
+  char word[24];  // NUL-terminated; 23 usable bytes + terminator
+  int fontId;
+  uint16_t width;
+  uint8_t style;  // EpdFontFamily::Style narrowed to one byte
+  bool valid;  // false = slot empty (BSS-initialised to 0)
+};
+
+// Power-of-two size → slot selection via fast bitmask AND.
+// 128 entries × 32 bytes = 4 KB in BSS; covers typical paragraph vocabulary
+// with a low collision rate even for German compound-heavy prose.
+static constexpr uint32_t WORD_WIDTH_CACHE_SIZE = 128;
+static constexpr uint32_t WORD_WIDTH_CACHE_MASK = WORD_WIDTH_CACHE_SIZE - 1;
+static WordWidthCacheEntry s_wordWidthCache[WORD_WIDTH_CACHE_SIZE];
+
+// FNV-1a over the word bytes, then XOR-folded with fontId and style.
+static uint32_t wordWidthCacheHash(const char* str, const size_t len, const int fontId, const uint8_t style) {
+  uint32_t h = 2166136261u;  // FNV offset basis
+  for (size_t i = 0; i < len; ++i) {
+    h ^= static_cast<uint8_t>(str[i]);
+    h *= 16777619u;  // FNV prime
+  }
+  h ^= static_cast<uint32_t>(fontId);
+  h *= 16777619u;
+  h ^= style;
+  return h;
+}
+
+// Returns the cached width for (word, style, fontId), measuring and caching
+// on a miss.  Appending a hyphen is not supported — those measurements are
+// word-fragment lookups that will not repeat and must not pollute the cache.
+static uint16_t cachedMeasureWordWidth(const GfxRenderer& renderer, const int fontId, const std::string& word,
+                                       const EpdFontFamily::Style style) {
+  const size_t len = word.size();
+  if (len >= 24) {
+    return measureWordWidth(renderer, fontId, word, style);
+  }
+
+  const uint8_t styleByte = static_cast<uint8_t>(style);
+  const char* const wordCStr = word.c_str();
+
+  const uint32_t slot = wordWidthCacheHash(wordCStr, len, fontId, styleByte) & WORD_WIDTH_CACHE_MASK;
+  auto& e = s_wordWidthCache[slot];
+
+  if (e.valid && e.fontId == fontId && e.style == styleByte && memcmp(e.word, wordCStr, len + 1) == 0) {
+    return e.width;  // O(1) cache hit
+  }
+
+  const uint16_t w = measureWordWidth(renderer, fontId, word, style);
+  memcpy(e.word, wordCStr, len + 1);
+  e.fontId = fontId;
+  e.width = w;
+  e.style = styleByte;
+  e.valid = true;
+  return w;
+}
+
 }  // namespace

 void ParsedText::addWord(std::string word, const EpdFontFamily::Style fontStyle, const bool underline,
@@ -131,7 +206,7 @@ std::vector<uint16_t> ParsedText::calculateWordWidths(const GfxRenderer& rendere
  wordWidths.reserve(words.size());

  for (size_t i = 0; i < words.size(); ++i) {
-    wordWidths.push_back(measureWordWidth(renderer, fontId, words[i], wordStyles[i]));
+    wordWidths.push_back(cachedMeasureWordWidth(renderer, fontId, words[i], wordStyles[i]));
  }

  return wordWidths;
@@ -241,6 +316,7 @@ std::vector<size_t> ParsedText::computeLineBreaks(const GfxRenderer& renderer, c

  // Stores the index of the word that starts the next line (last_word_index + 1)
  std::vector<size_t> lineBreakIndices;
+  lineBreakIndices.reserve(totalWordCount / 8 + 1);
  size_t currentWordIndex = 0;

  while (currentWordIndex < totalWordCount) {
@@ -376,8 +452,11 @@ bool ParsedText::hyphenateWordAtIndex(const size_t wordIndex, const int availabl
  size_t chosenOffset = 0;
  int chosenWidth = -1;
  bool chosenNeedsHyphen = true;
+  std::string prefix;
+  prefix.reserve(word.size());

  // Iterate over each legal breakpoint and retain the widest prefix that still fits.
+  // Breakpoints are in ascending order, so once a prefix is too wide, all subsequent ones will be too.
  for (const auto& info : breakInfos) {
    const size_t offset = info.byteOffset;
    if (offset == 0 || offset >= word.size()) {
@@ -385,9 +464,13 @@ bool ParsedText::hyphenateWordAtIndex(const size_t wordIndex, const int availabl
    }

    const bool needsHyphen = info.requiresInsertedHyphen;
-    const int prefixWidth = measureWordWidth(renderer, fontId, word.substr(0, offset), style, needsHyphen);
-    if (prefixWidth > availableWidth || prefixWidth <= chosenWidth) {
-      continue;  // Skip if too wide or not an improvement
+    prefix.assign(word, 0, offset);
+    const int prefixWidth = measureWordWidth(renderer, fontId, prefix, style, needsHyphen);
+    if (prefixWidth > availableWidth) {
+      break;  // Ascending order: all subsequent breakpoints yield wider prefixes
+    }
+    if (prefixWidth <= chosenWidth) {
+      continue;  // Not an improvement
    }

    chosenWidth = prefixWidth;
--- a/lib/Epub/Epub/hyphenation/HyphenationCommon.cpp
+++ b/lib/Epub/Epub/hyphenation/HyphenationCommon.cpp
@@ -95,8 +95,6 @@ bool isPunctuation(const uint32_t cp) {
    case '}':
    case '[':
    case ']':
-    case '/':
-    case 0x2039:  // ‹
    case 0x203A:  // ›
    case 0x2026:  // …
      return true;
@@ -109,6 +107,7 @@ bool isAsciiDigit(const uint32_t cp) { return cp >= '0' && cp <= '9'; }

 bool isExplicitHyphen(const uint32_t cp) {
  switch (cp) {
+    case '/':
    case '-':
    case 0x00AD:  // soft hyphen
    case 0x058A:  // Armenian hyphen
--- a/lib/Epub/Epub/hyphenation/Hyphenator.cpp
+++ b/lib/Epub/Epub/hyphenation/Hyphenator.cpp
@@ -1,10 +1,8 @@
 #include "Hyphenator.h"

-#include <algorithm>
 #include <vector>

 #include "HyphenationCommon.h"
-#include "LanguageHyphenator.h"
 #include "LanguageRegistry.h"

 const LanguageHyphenator* Hyphenator::cachedHyphenator_ = nullptr;
@@ -34,25 +32,20 @@ size_t byteOffsetForIndex(const std::vector<CodepointInfo>& cps, const size_t in
 }

 // Builds a vector of break information from explicit hyphen markers in the given codepoints.
-// Only hyphens that appear between two alphabetic characters are considered valid breaks.
-//
-// Example: "US-Satellitensystems" (cps: U, S, -, S, a, t, ...)
-//   -> finds '-' at index 2 with alphabetic neighbors 'S' and 'S'
-//   -> returns one BreakInfo at the byte offset of 'S' (the char after '-'),
-//      with requiresInsertedHyphen=false because '-' is already visible.
-//
-// Example: "Satel\u00ADliten" (soft-hyphen between 'l' and 'l')
-//   -> returns one BreakInfo with requiresInsertedHyphen=true (soft-hyphen
-//      is invisible and needs a visible '-' when the break is used).
 std::vector<Hyphenator::BreakInfo> buildExplicitBreakInfos(const std::vector<CodepointInfo>& cps) {
  std::vector<Hyphenator::BreakInfo> breaks;

  for (size_t i = 1; i + 1 < cps.size(); ++i) {
    const uint32_t cp = cps[i].value;
-    if (!isExplicitHyphen(cp) || !isAlphabetic(cps[i - 1].value) || !isAlphabetic(cps[i + 1].value)) {
+    if (!isExplicitHyphen(cp)) {
+      continue;
+    }
+    if ((cp == '/' || cp == '-') && cps[i + 1].value == cp) {
+      continue;
+    }
+    if (cp != '/' && cp != '-' && (!isAlphabetic(cps[i - 1].value) || !isAlphabetic(cps[i + 1].value))) {
      continue;
    }
-    // Offset points to the next codepoint so rendering starts after the hyphen marker.
    breaks.push_back({cps[i + 1].byteOffset, isSoftHyphen(cp)});
  }

@@ -74,43 +67,6 @@ std::vector<Hyphenator::BreakInfo> Hyphenator::breakOffsets(const std::string& w
  // Explicit hyphen markers (soft or hard) take precedence over language breaks.
  auto explicitBreakInfos = buildExplicitBreakInfos(cps);
  if (!explicitBreakInfos.empty()) {
-    // When a word contains explicit hyphens we also run Liang patterns on each alphabetic
-    // segment between them. Without this, "US-Satellitensystems" would only offer one split
-    // point (after "US-"), making it impossible to break mid-"Satellitensystems" even when
-    // "US-Satelliten-" would fit on the line.
-    //
-    // Example: "US-Satellitensystems"
-    //   Segments: ["US", "Satellitensystems"]
-    //   Explicit break: after "US-"           -> @3  (no inserted hyphen)
-    //   Pattern breaks on "Satellitensystems" -> @5  Sa|tel  (+hyphen)
-    //                                            @8  Satel|li  (+hyphen)
-    //                                            @10 Satelli|ten  (+hyphen)
-    //                                            @13 Satelliten|sys  (+hyphen)
-    //                                            @16 Satellitensys|tems  (+hyphen)
-    //   Result: 6 sorted break points; the line-breaker picks the widest prefix that fits.
-    if (hyphenator) {
-      size_t segStart = 0;
-      for (size_t i = 0; i <= cps.size(); ++i) {
-        const bool atEnd = (i == cps.size());
-        const bool atHyphen = !atEnd && isExplicitHyphen(cps[i].value);
-        if (atEnd || atHyphen) {
-          if (i > segStart) {
-            std::vector<CodepointInfo> segment(cps.begin() + segStart, cps.begin() + i);
-            auto segIndexes = hyphenator->breakIndexes(segment);
-            for (const size_t idx : segIndexes) {
-              const size_t cpIdx = segStart + idx;
-              if (cpIdx < cps.size()) {
-                explicitBreakInfos.push_back({cps[cpIdx].byteOffset, true});
-              }
-            }
-          }
-          segStart = i + 1;
-        }
-      }
-      // Merge explicit and pattern breaks into ascending byte-offset order.
-      std::sort(explicitBreakInfos.begin(), explicitBreakInfos.end(),
-                [](const BreakInfo& a, const BreakInfo& b) { return a.byteOffset < b.byteOffset; });
-    }
    return explicitBreakInfos;
  }

--- a/lib/GfxRenderer/GfxRenderer.cpp
+++ b/lib/GfxRenderer/GfxRenderer.cpp
@@ -3,6 +3,8 @@
 #include <Logging.h>
 #include <Utf8.h>

+#include <cstring>
+
 const uint8_t* GfxRenderer::getGlyphBitmap(const EpdFontData* fontData, const EpdGlyph* glyph) const {
  if (fontData->groups != nullptr) {
    if (!fontDecompressor) {
@@ -271,15 +273,34 @@ void GfxRenderer::drawLine(int x1, int y1, int x2, int y2, const bool state) con
    if (y2 < y1) {
      std::swap(y1, y2);
    }
-    for (int y = y1; y <= y2; y++) {
-      drawPixel(x1, y, state);
+    // In Portrait/PortraitInverted a logical vertical line maps to a physical horizontal span.
+    switch (orientation) {
+      case Portrait:
+        fillPhysicalHSpan(HalDisplay::DISPLAY_HEIGHT - 1 - x1, y1, y2, state);
+        return;
+      case PortraitInverted:
+        fillPhysicalHSpan(x1, HalDisplay::DISPLAY_WIDTH - 1 - y2, HalDisplay::DISPLAY_WIDTH - 1 - y1, state);
+        return;
+      default:
+        for (int y = y1; y <= y2; y++) drawPixel(x1, y, state);
+        return;
    }
  } else if (y1 == y2) {
    if (x2 < x1) {
      std::swap(x1, x2);
    }
-    for (int x = x1; x <= x2; x++) {
-      drawPixel(x, y1, state);
+    // In Landscape a logical horizontal line maps to a physical horizontal span.
+    switch (orientation) {
+      case LandscapeCounterClockwise:
+        fillPhysicalHSpan(y1, x1, x2, state);
+        return;
+      case LandscapeClockwise:
+        fillPhysicalHSpan(HalDisplay::DISPLAY_HEIGHT - 1 - y1, HalDisplay::DISPLAY_WIDTH - 1 - x2,
+                          HalDisplay::DISPLAY_WIDTH - 1 - x1, state);
+        return;
+      default:
+        for (int x = x1; x <= x2; x++) drawPixel(x, y1, state);
+        return;
    }
  } else {
    // Bresenham's line algorithm — integer arithmetic only
@@ -408,9 +429,80 @@ void GfxRenderer::drawRoundedRect(const int x, const int y, const int width, con
  }
 }

+// Write a patterned horizontal span directly into the physical framebuffer with byte-level operations.
+// Handles partial left/right bytes and fills the aligned middle with memset.
+// Bit layout: MSB-first (bit 7 = phyX=0, bit 0 = phyX=7); 0 bits = dark pixel, 1 bits = white pixel.
+void GfxRenderer::fillPhysicalHSpanByte(const int phyY, const int phyX_start, const int phyX_end,
+                                        const uint8_t patternByte) const {
+  const int cX0 = std::max(phyX_start, 0);
+  const int cX1 = std::min(phyX_end, static_cast<int>(HalDisplay::DISPLAY_WIDTH) - 1);
+  if (cX0 > cX1 || phyY < 0 || phyY >= static_cast<int>(HalDisplay::DISPLAY_HEIGHT)) return;
+
+  uint8_t* const row = frameBuffer + phyY * HalDisplay::DISPLAY_WIDTH_BYTES;
+  const int startByte = cX0 >> 3;
+  const int endByte = cX1 >> 3;
+  const int leftBits = cX0 & 7;
+  const int rightBits = cX1 & 7;
+
+  if (startByte == endByte) {
+    const uint8_t fillMask = (0xFF >> leftBits) & ~(0xFF >> (rightBits + 1));
+    row[startByte] = (row[startByte] & ~fillMask) | (patternByte & fillMask);
+    return;
+  }
+
+  // Left partial byte
+  if (leftBits != 0) {
+    const uint8_t fillMask = 0xFF >> leftBits;
+    row[startByte] = (row[startByte] & ~fillMask) | (patternByte & fillMask);
+  }
+
+  // Full bytes in the middle
+  const int fullStart = (leftBits == 0) ? startByte : startByte + 1;
+  const int fullEnd = (rightBits == 7) ? endByte : endByte - 1;
+  if (fullStart <= fullEnd) {
+    memset(row + fullStart, patternByte, static_cast<size_t>(fullEnd - fullStart + 1));
+  }
+
+  // Right partial byte
+  if (rightBits != 7) {
+    const uint8_t fillMask = ~(0xFF >> (rightBits + 1));
+    row[endByte] = (row[endByte] & ~fillMask) | (patternByte & fillMask);
+  }
+}
+
+// Thin wrapper: state=true → 0x00 (all dark), false → 0xFF (all white).
+void GfxRenderer::fillPhysicalHSpan(const int phyY, const int phyX_start, const int phyX_end, const bool state) const {
+  fillPhysicalHSpanByte(phyY, phyX_start, phyX_end, state ? 0x00 : 0xFF);
+}
+
 void GfxRenderer::fillRect(const int x, const int y, const int width, const int height, const bool state) const {
-  for (int fillY = y; fillY < y + height; fillY++) {
-    drawLine(x, fillY, x + width - 1, fillY, state);
+  if (width <= 0 || height <= 0) return;
+
+  // For each orientation, one logical dimension maps to a constant physical row, allowing the
+  // perpendicular dimension to be written as a byte-level span — eliminating per-pixel overhead.
+  switch (orientation) {
+    case Portrait:
+      for (int lx = x; lx < x + width; lx++) {
+        fillPhysicalHSpan(HalDisplay::DISPLAY_HEIGHT - 1 - lx, y, y + height - 1, state);
+      }
+      return;
+    case PortraitInverted:
+      for (int lx = x; lx < x + width; lx++) {
+        fillPhysicalHSpan(lx, HalDisplay::DISPLAY_WIDTH - 1 - (y + height - 1), HalDisplay::DISPLAY_WIDTH - 1 - y,
+                          state);
+      }
+      return;
+    case LandscapeCounterClockwise:
+      for (int ly = y; ly < y + height; ly++) {
+        fillPhysicalHSpan(ly, x, x + width - 1, state);
+      }
+      return;
+    case LandscapeClockwise:
+      for (int ly = y; ly < y + height; ly++) {
+        fillPhysicalHSpan(HalDisplay::DISPLAY_HEIGHT - 1 - ly, HalDisplay::DISPLAY_WIDTH - 1 - (x + width - 1),
+                          HalDisplay::DISPLAY_WIDTH - 1 - x, state);
+      }
+      return;
  }
 }

@@ -447,17 +539,77 @@ void GfxRenderer::fillRectDither(const int x, const int y, const int width, cons
    fillRect(x, y, width, height, true);
  } else if (color == Color::White) {
    fillRect(x, y, width, height, false);
-  } else if (color == Color::LightGray) {
-    for (int fillY = y; fillY < y + height; fillY++) {
-      for (int fillX = x; fillX < x + width; fillX++) {
-        drawPixelDither<Color::LightGray>(fillX, fillY);
-      }
-    }
  } else if (color == Color::DarkGray) {
-    for (int fillY = y; fillY < y + height; fillY++) {
-      for (int fillX = x; fillX < x + width; fillX++) {
-        drawPixelDither<Color::DarkGray>(fillX, fillY);
-      }
+    // Pattern: dark where (phyX + phyY) % 2 == 0 (alternating checkerboard).
+    // Byte patterns (phyY even / phyY odd):
+    // Portrait / PortraitInverted: 0xAA / 0x55
+    // LandscapeCW / LandscapeCCW: 0x55 / 0xAA
+    switch (orientation) {
+      case Portrait:
+        for (int lx = x; lx < x + width; lx++) {
+          const int phyY = HalDisplay::DISPLAY_HEIGHT - 1 - lx;
+          const uint8_t pb = (phyY % 2 == 0) ? 0xAA : 0x55;
+          fillPhysicalHSpanByte(phyY, y, y + height - 1, pb);
+        }
+        return;
+      case PortraitInverted:
+        for (int lx = x; lx < x + width; lx++) {
+          const int phyY = lx;
+          const uint8_t pb = (phyY % 2 == 0) ? 0xAA : 0x55;
+          fillPhysicalHSpanByte(phyY, HalDisplay::DISPLAY_WIDTH - 1 - (y + height - 1),
+                                HalDisplay::DISPLAY_WIDTH - 1 - y, pb);
+        }
+        return;
+      case LandscapeCounterClockwise:
+        for (int ly = y; ly < y + height; ly++) {
+          const int phyY = ly;
+          const uint8_t pb = (phyY % 2 == 0) ? 0x55 : 0xAA;
+          fillPhysicalHSpanByte(phyY, x, x + width - 1, pb);
+        }
+        return;
+      case LandscapeClockwise:
+        for (int ly = y; ly < y + height; ly++) {
+          const int phyY = HalDisplay::DISPLAY_HEIGHT - 1 - ly;
+          const uint8_t pb = (phyY % 2 == 0) ? 0x55 : 0xAA;
+          fillPhysicalHSpanByte(phyY, HalDisplay::DISPLAY_WIDTH - 1 - (x + width - 1),
+                                HalDisplay::DISPLAY_WIDTH - 1 - x, pb);
+        }
+        return;
+    }
+  } else if (color == Color::LightGray) {
+    // Pattern: dark where phyX % 2 == 0 && phyY % 2 == 0 (1-in-4 pixels dark).
+    // Rows that would be all-white are skipped entirely.
+    switch (orientation) {
+      case Portrait:
+        for (int lx = x; lx < x + width; lx++) {
+          const int phyY = HalDisplay::DISPLAY_HEIGHT - 1 - lx;
+          if (phyY % 2 == 0) continue;
+          fillPhysicalHSpanByte(phyY, y, y + height - 1, 0x55);
+        }
+        return;
+      case PortraitInverted:
+        for (int lx = x; lx < x + width; lx++) {
+          const int phyY = lx;
+          if (phyY % 2 != 0) continue;
+          fillPhysicalHSpanByte(phyY, HalDisplay::DISPLAY_WIDTH - 1 - (y + height - 1),
+                                HalDisplay::DISPLAY_WIDTH - 1 - y, 0xAA);
+        }
+        return;
+      case LandscapeCounterClockwise:
+        for (int ly = y; ly < y + height; ly++) {
+          const int phyY = ly;
+          if (phyY % 2 != 0) continue;
+          fillPhysicalHSpanByte(phyY, x, x + width - 1, 0x55);
+        }
+        return;
+      case LandscapeClockwise:
+        for (int ly = y; ly < y + height; ly++) {
+          const int phyY = HalDisplay::DISPLAY_HEIGHT - 1 - ly;
+          if (phyY % 2 == 0) continue;
+          fillPhysicalHSpanByte(phyY, HalDisplay::DISPLAY_WIDTH - 1 - (x + width - 1),
+                                HalDisplay::DISPLAY_WIDTH - 1 - x, 0xAA);
+        }
+        return;
    }
  }
 }
@@ -799,9 +951,16 @@ void GfxRenderer::fillPolygon(const int* xPoints, const int* yPoints, int numPoi
      if (startX < 0) startX = 0;
      if (endX >= getScreenWidth()) endX = getScreenWidth() - 1;

-      // Draw horizontal line
-      for (int x = startX; x <= endX; x++) {
-        drawPixel(x, scanY, state);
+      // In Landscape orientations, horizontal scanlines map to physical horizontal spans.
+      if (orientation == LandscapeCounterClockwise) {
+        fillPhysicalHSpan(scanY, startX, endX, state);
+      } else if (orientation == LandscapeClockwise) {
+        fillPhysicalHSpan(HalDisplay::DISPLAY_HEIGHT - 1 - scanY, HalDisplay::DISPLAY_WIDTH - 1 - endX,
+                          HalDisplay::DISPLAY_WIDTH - 1 - startX, state);
+      } else {
+        for (int px = startX; px <= endX; px++) {
+          drawPixel(px, scanY, state);
+        }
      }
    }
  }
--- a/lib/GfxRenderer/GfxRenderer.h
+++ b/lib/GfxRenderer/GfxRenderer.h
@@ -45,6 +45,14 @@ class GfxRenderer {
  void drawPixelDither(int x, int y) const;
  template <Color color>
  void fillArc(int maxRadius, int cx, int cy, int xDir, int yDir) const;
+  // Write a patterned horizontal span directly to the physical framebuffer using byte-level operations.
+  // phyY: physical row; phyX_start/phyX_end: inclusive physical column range.
+  // patternByte is repeated across the span; partial edge bytes are blended with existing content.
+  // Bit layout: MSB-first (bit 7 = phyX=0); 0 bits = dark pixel, 1 bits = white pixel.
+  void fillPhysicalHSpanByte(int phyY, int phyX_start, int phyX_end, uint8_t patternByte) const;
+  // Write a solid horizontal span directly to the physical framebuffer using byte-level operations.
+  // Thin wrapper around fillPhysicalHSpanByte: state=true → 0x00 (dark), false → 0xFF (white).
+  void fillPhysicalHSpan(int phyY, int phyX_start, int phyX_end, bool state) const;

 public:
  explicit GfxRenderer(HalDisplay& halDisplay)
--- a/lib/I18n/translations/english.yaml
+++ b/lib/I18n/translations/english.yaml
@@ -344,6 +344,7 @@ STR_AUTO_TURN_PAGES_PER_MIN: "Auto Turn (Pages Per Minute)"

 STR_CAT_CLOCK: "Clock"
 STR_CLOCK: "Clock"
+STR_OFF: "Off"
 STR_CLOCK_AMPM: "AM/PM"
 STR_CLOCK_24H: "24 Hour"
 STR_SET_TIME: "Set Time"
--- a/lib/KOReaderSync/KOReaderCredentialStore.cpp
+++ b/lib/KOReaderSync/KOReaderCredentialStore.cpp
@@ -3,81 +3,73 @@
 #include <HalStorage.h>
 #include <Logging.h>
 #include <MD5Builder.h>
-#include <ObfuscationUtils.h>
 #include <Serialization.h>

-#include "../../src/JsonSettingsIO.h"
-
 // Initialize the static instance
 KOReaderCredentialStore KOReaderCredentialStore::instance;

 namespace {
-// File format version (for binary migration)
+// File format version
 constexpr uint8_t KOREADER_FILE_VERSION = 1;

-// File paths
-constexpr char KOREADER_FILE_BIN[] = "/.crosspoint/koreader.bin";
-constexpr char KOREADER_FILE_JSON[] = "/.crosspoint/koreader.json";
-constexpr char KOREADER_FILE_BAK[] = "/.crosspoint/koreader.bin.bak";
+// KOReader credentials file path
+constexpr char KOREADER_FILE[] = "/.crosspoint/koreader.bin";

 // Default sync server URL
 constexpr char DEFAULT_SERVER_URL[] = "https://sync.koreader.rocks:443";

-// Legacy obfuscation key - "KOReader" in ASCII (only used for binary migration)
-constexpr uint8_t LEGACY_OBFUSCATION_KEY[] = {0x4B, 0x4F, 0x52, 0x65, 0x61, 0x64, 0x65, 0x72};
-constexpr size_t LEGACY_KEY_LENGTH = sizeof(LEGACY_OBFUSCATION_KEY);
-
-void legacyDeobfuscate(std::string& data) {
-  for (size_t i = 0; i < data.size(); i++) {
-    data[i] ^= LEGACY_OBFUSCATION_KEY[i % LEGACY_KEY_LENGTH];
-  }
-}
+// Obfuscation key - "KOReader" in ASCII
+// This is NOT cryptographic security, just prevents casual file reading
+constexpr uint8_t OBFUSCATION_KEY[] = {0x4B, 0x4F, 0x52, 0x65, 0x61, 0x64, 0x65, 0x72};
+constexpr size_t KEY_LENGTH = sizeof(OBFUSCATION_KEY);
 }  // namespace

+void KOReaderCredentialStore::obfuscate(std::string& data) const {
+  for (size_t i = 0; i < data.size(); i++) {
+    data[i] ^= OBFUSCATION_KEY[i % KEY_LENGTH];
+  }
+}
+
 bool KOReaderCredentialStore::saveToFile() const {
+  // Make sure the directory exists
  Storage.mkdir("/.crosspoint");
-  return JsonSettingsIO::saveKOReader(*this, KOREADER_FILE_JSON);
-}

-bool KOReaderCredentialStore::loadFromFile() {
-  // Try JSON first
-  if (Storage.exists(KOREADER_FILE_JSON)) {
-    String json = Storage.readFile(KOREADER_FILE_JSON);
-    if (!json.isEmpty()) {
-      bool resave = false;
-      bool result = JsonSettingsIO::loadKOReader(*this, json.c_str(), &resave);
-      if (result && resave) {
-        saveToFile();
-        LOG_DBG("KRS", "Resaved KOReader credentials to update format");
-      }
-      return result;
-    }
-  }
-
-  // Fall back to binary migration
-  if (Storage.exists(KOREADER_FILE_BIN)) {
-    if (loadFromBinaryFile()) {
-      if (saveToFile()) {
-        Storage.rename(KOREADER_FILE_BIN, KOREADER_FILE_BAK);
-        LOG_DBG("KRS", "Migrated koreader.bin to koreader.json");
-        return true;
-      } else {
-        LOG_ERR("KRS", "Failed to save KOReader credentials during migration");
-        return false;
-      }
-    }
-  }
-
-  LOG_DBG("KRS", "No credentials file found");
-  return false;
-}
-
-bool KOReaderCredentialStore::loadFromBinaryFile() {
  FsFile file;
-  if (!Storage.openFileForRead("KRS", KOREADER_FILE_BIN, file)) {
+  if (!Storage.openFileForWrite("KRS", KOREADER_FILE, file)) {
    return false;
  }

+  // Write header
+  serialization::writePod(file, KOREADER_FILE_VERSION);
+
+  // Write username (plaintext - not particularly sensitive)
+  serialization::writeString(file, username);
+  LOG_DBG("KRS", "Saving username: %s", username.c_str());
+
+  // Write password (obfuscated)
+  std::string obfuscatedPwd = password;
+  obfuscate(obfuscatedPwd);
+  serialization::writeString(file, obfuscatedPwd);
+
+  // Write server URL
+  serialization::writeString(file, serverUrl);
+
+  // Write match method
+  serialization::writePod(file, static_cast<uint8_t>(matchMethod));
+
+  file.close();
+  LOG_DBG("KRS", "Saved KOReader credentials to file");
+  return true;
+}
+
+bool KOReaderCredentialStore::loadFromFile() {
+  FsFile file;
+  if (!Storage.openFileForRead("KRS", KOREADER_FILE, file)) {
+    LOG_DBG("KRS", "No credentials file found");
+    return false;
+  }
+
+  // Read and verify version
  uint8_t version;
  serialization::readPod(file, version);
  if (version != KOREADER_FILE_VERSION) {
@@ -86,25 +78,29 @@ bool KOReaderCredentialStore::loadFromBinaryFile() {
    return false;
  }

+  // Read username
  if (file.available()) {
    serialization::readString(file, username);
  } else {
    username.clear();
  }

+  // Read and deobfuscate password
  if (file.available()) {
    serialization::readString(file, password);
-    legacyDeobfuscate(password);
+    obfuscate(password);  // XOR is symmetric, so same function deobfuscates
  } else {
    password.clear();
  }

+  // Read server URL
  if (file.available()) {
    serialization::readString(file, serverUrl);
  } else {
    serverUrl.clear();
  }

+  // Read match method
  if (file.available()) {
    uint8_t method;
    serialization::readPod(file, method);
@@ -114,7 +110,7 @@ bool KOReaderCredentialStore::loadFromBinaryFile() {
  }

  file.close();
-  LOG_DBG("KRS", "Loaded KOReader credentials from binary for user: %s", username.c_str());
+  LOG_DBG("KRS", "Loaded KOReader credentials for user: %s", username.c_str());
  return true;
 }

--- a/lib/KOReaderSync/KOReaderCredentialStore.h
+++ b/lib/KOReaderSync/KOReaderCredentialStore.h
@@ -8,17 +8,10 @@ enum class DocumentMatchMethod : uint8_t {
  BINARY = 1,    // Match by partial MD5 of file content (more accurate, but files must be identical)
 };

-class KOReaderCredentialStore;
-namespace JsonSettingsIO {
-bool saveKOReader(const KOReaderCredentialStore& store, const char* path);
-bool loadKOReader(KOReaderCredentialStore& store, const char* json, bool* needsResave);
-}  // namespace JsonSettingsIO
-
 /**
 * Singleton class for storing KOReader sync credentials on the SD card.
- * Passwords are XOR-obfuscated with the device's unique hardware MAC address
- * and base64-encoded before writing to JSON (not cryptographically secure,
- * but prevents casual reading and ties credentials to the specific device).
+ * Credentials are stored in /sd/.crosspoint/koreader.bin with basic
+ * XOR obfuscation to prevent casual reading (not cryptographically secure).
 */
 class KOReaderCredentialStore {
 private:
@@ -31,10 +24,8 @@ class KOReaderCredentialStore {
  // Private constructor for singleton
  KOReaderCredentialStore() = default;

-  bool loadFromBinaryFile();
-
-  friend bool JsonSettingsIO::saveKOReader(const KOReaderCredentialStore&, const char*);
-  friend bool JsonSettingsIO::loadKOReader(KOReaderCredentialStore&, const char*, bool*);
+  // XOR obfuscation (symmetric - same for encode/decode)
+  void obfuscate(std::string& data) const;

 public:
  // Delete copy constructor and assignment
--- a/lib/KOReaderSync/KOReaderDocumentId.cpp
+++ b/lib/KOReaderSync/KOReaderDocumentId.cpp
@@ -4,6 +4,8 @@
 #include <Logging.h>
 #include <MD5Builder.h>

+#include <functional>
+
 namespace {
 // Extract filename from path (everything after last '/')
 std::string getFilename(const std::string& path) {
@@ -15,6 +17,131 @@ std::string getFilename(const std::string& path) {
 }
 }  // namespace

+std::string KOReaderDocumentId::getCacheFilePath(const std::string& filePath) {
+  // Mirror the Epub cache directory convention so the hash file shares the
+  // same per-book folder as other cached data.
+  return std::string("/.crosspoint/epub_") + std::to_string(std::hash<std::string>{}(filePath)) +
+         "/koreader_docid.txt";
+}
+
+std::string KOReaderDocumentId::loadCachedHash(const std::string& cacheFilePath, const size_t fileSize,
+                                               const std::string& currentFingerprint) {
+  if (!Storage.exists(cacheFilePath.c_str())) {
+    return "";
+  }
+
+  const String content = Storage.readFile(cacheFilePath.c_str());
+  if (content.isEmpty()) {
+    return "";
+  }
+
+  // Format: "<filesize>:<fingerprint>\n<32-char-hex-hash>"
+  const int newlinePos = content.indexOf('\n');
+  if (newlinePos < 0) {
+    return "";
+  }
+
+  const String header = content.substring(0, newlinePos);
+  const int colonPos = header.indexOf(':');
+  if (colonPos < 0) {
+    LOG_DBG("KODoc", "Hash cache invalidated: header missing fingerprint");
+    return "";
+  }
+
+  const String sizeTok = header.substring(0, colonPos);
+  const String fpTok = header.substring(colonPos + 1);
+
+  // Validate the filesize token – it must consist of ASCII digits and parse
+  // correctly to the expected size.
+  bool digitsOnly = true;
+  for (size_t i = 0; i < sizeTok.length(); ++i) {
+    const char ch = sizeTok[i];
+    if (ch < '0' || ch > '9') {
+      digitsOnly = false;
+      break;
+    }
+  }
+  if (!digitsOnly) {
+    LOG_DBG("KODoc", "Hash cache invalidated: size token not numeric ('%s')", sizeTok.c_str());
+    return "";
+  }
+
+  const long parsed = sizeTok.toInt();
+  if (parsed < 0) {
+    LOG_DBG("KODoc", "Hash cache invalidated: size token parse error ('%s')", sizeTok.c_str());
+    return "";
+  }
+  const size_t cachedSize = static_cast<size_t>(parsed);
+  if (cachedSize != fileSize) {
+    LOG_DBG("KODoc", "Hash cache invalidated: file size or fingerprint changed (%zu -> %zu)", cachedSize, fileSize);
+    return "";
+  }
+
+  // Validate stored fingerprint format (8 hex characters)
+  if (fpTok.length() != 8) {
+    LOG_DBG("KODoc", "Hash cache invalidated: bad fingerprint length (%zu)", fpTok.length());
+    return "";
+  }
+  for (size_t i = 0; i < fpTok.length(); ++i) {
+    char c = fpTok[i];
+    bool hex = (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F');
+    if (!hex) {
+      LOG_DBG("KODoc", "Hash cache invalidated: non-hex character '%c' in fingerprint", c);
+      return "";
+    }
+  }
+
+  {
+    String currentFpStr(currentFingerprint.c_str());
+    if (fpTok != currentFpStr) {
+      LOG_DBG("KODoc", "Hash cache invalidated: fingerprint changed (%s != %s)", fpTok.c_str(),
+              currentFingerprint.c_str());
+      return "";
+    }
+  }
+
+  std::string hash = content.substring(newlinePos + 1).c_str();
+  // Trim any trailing whitespace / line endings
+  while (!hash.empty() && (hash.back() == '\n' || hash.back() == '\r' || hash.back() == ' ')) {
+    hash.pop_back();
+  }
+
+  // Hash must be exactly 32 hex characters.
+  if (hash.size() != 32) {
+    LOG_DBG("KODoc", "Hash cache invalidated: wrong hash length (%zu)", hash.size());
+    return "";
+  }
+  for (char c : hash) {
+    if (!((c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F'))) {
+      LOG_DBG("KODoc", "Hash cache invalidated: non-hex character '%c' in hash", c);
+      return "";
+    }
+  }
+
+  LOG_DBG("KODoc", "Hash cache hit: %s", hash.c_str());
+  return hash;
+}
+
+void KOReaderDocumentId::saveCachedHash(const std::string& cacheFilePath, const size_t fileSize,
+                                        const std::string& fingerprint, const std::string& hash) {
+  // Ensure the book's cache directory exists before writing
+  const size_t lastSlash = cacheFilePath.rfind('/');
+  if (lastSlash != std::string::npos) {
+    Storage.ensureDirectoryExists(cacheFilePath.substr(0, lastSlash).c_str());
+  }
+
+  // Format: "<filesize>:<fingerprint>\n<hash>"
+  String content(std::to_string(fileSize).c_str());
+  content += ':';
+  content += fingerprint.c_str();
+  content += '\n';
+  content += hash.c_str();
+
+  if (!Storage.writeFile(cacheFilePath.c_str(), content)) {
+    LOG_DBG("KODoc", "Failed to write hash cache to %s", cacheFilePath.c_str());
+  }
+}
+
 std::string KOReaderDocumentId::calculateFromFilename(const std::string& filePath) {
  const std::string filename = getFilename(filePath);
  if (filename.empty()) {
@@ -49,6 +176,28 @@ std::string KOReaderDocumentId::calculate(const std::string& filePath) {
  }

  const size_t fileSize = file.fileSize();
+
+  // Compute a lightweight fingerprint from the file's modification time.
+  // The underlying FsFile API provides getModifyDateTime which returns two
+  // packed 16-bit values (date and time).  Concatenate these as eight hex
+  // digits to produce the token stored in the cache header.
+  uint16_t date = 0, time = 0;
+  if (!file.getModifyDateTime(&date, &time)) {
+    date = 0;
+    time = 0;
+  }
+  char fpBuf[9];
+  snprintf(fpBuf, sizeof(fpBuf), "%04x%04x", date, time);
+  const std::string fingerprintTok(fpBuf);
+
+  // Return persisted hash if the file size and fingerprint haven't changed.
+  const std::string cacheFilePath = getCacheFilePath(filePath);
+  const std::string cached = loadCachedHash(cacheFilePath, fileSize, fingerprintTok);
+  if (!cached.empty()) {
+    file.close();
+    return cached;
+  }
+
  LOG_DBG("KODoc", "Calculating hash for file: %s (size: %zu)", filePath.c_str(), fileSize);

  // Initialize MD5 builder
@@ -92,5 +241,7 @@ std::string KOReaderDocumentId::calculate(const std::string& filePath) {

  LOG_DBG("KODoc", "Hash calculated: %s (from %zu bytes)", result.c_str(), totalBytesRead);

+  saveCachedHash(cacheFilePath, fileSize, fingerprintTok, result);
+
  return result;
 }
--- a/lib/KOReaderSync/KOReaderDocumentId.h
+++ b/lib/KOReaderSync/KOReaderDocumentId.h
@@ -42,4 +42,31 @@ class KOReaderDocumentId {

  // Calculate offset for index i: 1024 << (2*i)
  static size_t getOffset(int i);
+
+  // Hash cache helpers
+  // Returns the path to the per-book cache file that stores the precomputed hash.
+  // Uses the same directory convention as the Epub cache (/.crosspoint/epub_<hash>/).
+  static std::string getCacheFilePath(const std::string& filePath);
+
+  // Returns the cached hash if the file size and fingerprint match, or empty
+  // string on miss/invalidation.
+  //
+  // The fingerprint is derived from the file's modification timestamp.  We
+  // call `FsFile::getModifyDateTime` to retrieve two 16‑bit packed values
+  // supplied by the filesystem: one for the date and one for the time.  These
+  // are concatenated and represented as eight hexadecimal digits in the form
+  // <date><time> (high 16 bits = packed date, low 16 bits = packed time).
+  //
+  // The resulting string serves as a lightweight change signal; any modification
+  // to the file's mtime will alter the packed date/time combo and invalidate
+  // the cache entry.  Since the full document hash is expensive to compute,
+  // using the packed timestamp gives us a quick way to detect modifications
+  // without reading file contents.
+  static std::string loadCachedHash(const std::string& cacheFilePath, size_t fileSize,
+                                    const std::string& currentFingerprint);
+
+  // Persists the computed hash alongside the file size and fingerprint (the
+  // modification-timestamp token) used to generate it.
+  static void saveCachedHash(const std::string& cacheFilePath, size_t fileSize, const std::string& fingerprint,
+                             const std::string& hash);
 };
--- a/lib/KOReaderSync/ProgressMapper.cpp
+++ b/lib/KOReaderSync/ProgressMapper.cpp
@@ -2,8 +2,11 @@

 #include <Logging.h>

+#include <algorithm>
 #include <cmath>

+#include "ChapterXPathIndexer.h"
+
 KOReaderPosition ProgressMapper::toKOReader(const std::shared_ptr<Epub>& epub, const CrossPointPosition& pos) {
  KOReaderPosition result;

@@ -16,8 +19,13 @@ KOReaderPosition ProgressMapper::toKOReader(const std::shared_ptr<Epub>& epub, c
  // Calculate overall book progress (0.0-1.0)
  result.percentage = epub->calculateProgress(pos.spineIndex, intraSpineProgress);

-  // Generate XPath with estimated paragraph position based on page
-  result.xpath = generateXPath(pos.spineIndex, pos.pageNumber, pos.totalPages);
+  // Generate the best available XPath for the current chapter position.
+  // Prefer element-level XPaths from a lightweight XHTML reparse; fall back
+  // to a synthetic chapter-level path if parsing fails.
+  result.xpath = ChapterXPathIndexer::findXPathForProgress(epub, pos.spineIndex, intraSpineProgress);
+  if (result.xpath.empty()) {
+    result.xpath = generateXPath(pos.spineIndex);
+  }

  // Get chapter info for logging
  const int tocIndex = epub->getTocIndexForSpineIndex(pos.spineIndex);
@@ -36,34 +44,69 @@ CrossPointPosition ProgressMapper::toCrossPoint(const std::shared_ptr<Epub>& epu
  result.pageNumber = 0;
  result.totalPages = 0;

-  const size_t bookSize = epub->getBookSize();
-  if (bookSize == 0) {
+  if (!epub || epub->getSpineItemsCount() <= 0) {
    return result;
  }

-  // Use percentage-based lookup for both spine and page positioning
-  // XPath parsing is unreliable since CrossPoint doesn't preserve detailed HTML structure
-  const size_t targetBytes = static_cast<size_t>(bookSize * koPos.percentage);
-
-  // Find the spine item that contains this byte position
  const int spineCount = epub->getSpineItemsCount();
-  bool spineFound = false;
-  for (int i = 0; i < spineCount; i++) {
-    const size_t cumulativeSize = epub->getCumulativeSpineItemSize(i);
-    if (cumulativeSize >= targetBytes) {
-      result.spineIndex = i;
-      spineFound = true;
-      break;
+
+  float resolvedIntraSpineProgress = -1.0f;
+  bool xpathExactMatch = false;
+  bool usedXPathMapping = false;
+
+  int xpathSpineIndex = -1;
+  if (ChapterXPathIndexer::tryExtractSpineIndexFromXPath(koPos.xpath, xpathSpineIndex) && xpathSpineIndex >= 0 &&
+      xpathSpineIndex < spineCount) {
+    float intraFromXPath = 0.0f;
+    if (ChapterXPathIndexer::findProgressForXPath(epub, xpathSpineIndex, koPos.xpath, intraFromXPath,
+                                                  xpathExactMatch)) {
+      result.spineIndex = xpathSpineIndex;
+      resolvedIntraSpineProgress = intraFromXPath;
+      usedXPathMapping = true;
    }
  }

-  // If no spine item was found (e.g., targetBytes beyond last cumulative size),
-  // default to the last spine item so we map to the end of the book instead of the beginning.
-  if (!spineFound && spineCount > 0) {
-    result.spineIndex = spineCount - 1;
+  if (!usedXPathMapping) {
+    const size_t bookSize = epub->getBookSize();
+    if (bookSize == 0) {
+      return result;
+    }
+
+    if (!std::isfinite(koPos.percentage)) {
+      return result;
+    }
+
+    const float sanitizedPercentage = std::clamp(koPos.percentage, 0.0f, 1.0f);
+    const size_t targetBytes = static_cast<size_t>(bookSize * sanitizedPercentage);
+
+    bool spineFound = false;
+    for (int i = 0; i < spineCount; i++) {
+      const size_t cumulativeSize = epub->getCumulativeSpineItemSize(i);
+      if (cumulativeSize >= targetBytes) {
+        result.spineIndex = i;
+        spineFound = true;
+        break;
+      }
+    }
+
+    if (!spineFound && spineCount > 0) {
+      result.spineIndex = spineCount - 1;
+    }
+
+    if (result.spineIndex < epub->getSpineItemsCount()) {
+      const size_t prevCumSize = (result.spineIndex > 0) ? epub->getCumulativeSpineItemSize(result.spineIndex - 1) : 0;
+      const size_t currentCumSize = epub->getCumulativeSpineItemSize(result.spineIndex);
+      const size_t spineSize = currentCumSize - prevCumSize;
+
+      if (spineSize > 0) {
+        const size_t bytesIntoSpine = (targetBytes > prevCumSize) ? (targetBytes - prevCumSize) : 0;
+        resolvedIntraSpineProgress = static_cast<float>(bytesIntoSpine) / static_cast<float>(spineSize);
+        resolvedIntraSpineProgress = std::max(0.0f, std::min(1.0f, resolvedIntraSpineProgress));
+      }
+    }
  }

-  // Estimate page number within the spine item using percentage
+  // Estimate page number within the selected spine item
  if (result.spineIndex < epub->getSpineItemsCount()) {
    const size_t prevCumSize = (result.spineIndex > 0) ? epub->getCumulativeSpineItemSize(result.spineIndex - 1) : 0;
    const size_t currentCumSize = epub->getCumulativeSpineItemSize(result.spineIndex);
@@ -71,12 +114,9 @@ CrossPointPosition ProgressMapper::toCrossPoint(const std::shared_ptr<Epub>& epu

    int estimatedTotalPages = 0;

-    // If we are in the same spine, use the known total pages
    if (result.spineIndex == currentSpineIndex && totalPagesInCurrentSpine > 0) {
      estimatedTotalPages = totalPagesInCurrentSpine;
-    }
-    // Otherwise try to estimate based on density from current spine
-    else if (currentSpineIndex >= 0 && currentSpineIndex < epub->getSpineItemsCount() && totalPagesInCurrentSpine > 0) {
+    } else if (currentSpineIndex >= 0 && currentSpineIndex < epub->getSpineItemsCount() && totalPagesInCurrentSpine > 0) {
      const size_t prevCurrCumSize =
          (currentSpineIndex > 0) ? epub->getCumulativeSpineItemSize(currentSpineIndex - 1) : 0;
      const size_t currCumSize = epub->getCumulativeSpineItemSize(currentSpineIndex);
@@ -91,24 +131,24 @@ CrossPointPosition ProgressMapper::toCrossPoint(const std::shared_ptr<Epub>& epu

    result.totalPages = estimatedTotalPages;

-    if (spineSize > 0 && estimatedTotalPages > 0) {
-      const size_t bytesIntoSpine = (targetBytes > prevCumSize) ? (targetBytes - prevCumSize) : 0;
-      const float intraSpineProgress = static_cast<float>(bytesIntoSpine) / static_cast<float>(spineSize);
-      const float clampedProgress = std::max(0.0f, std::min(1.0f, intraSpineProgress));
-      result.pageNumber = static_cast<int>(clampedProgress * estimatedTotalPages);
+    if (estimatedTotalPages > 0 && resolvedIntraSpineProgress >= 0.0f) {
+      const float clampedProgress = std::max(0.0f, std::min(1.0f, resolvedIntraSpineProgress));
+      result.pageNumber = static_cast<int>(clampedProgress * static_cast<float>(estimatedTotalPages));
      result.pageNumber = std::max(0, std::min(result.pageNumber, estimatedTotalPages - 1));
+    } else if (spineSize > 0 && estimatedTotalPages > 0) {
+      result.pageNumber = 0;
    }
  }

-  LOG_DBG("ProgressMapper", "KOReader -> CrossPoint: %.2f%% at %s -> spine=%d, page=%d", koPos.percentage * 100,
-          koPos.xpath.c_str(), result.spineIndex, result.pageNumber);
+  LOG_DBG("ProgressMapper", "KOReader -> CrossPoint: %.2f%% at %s -> spine=%d, page=%d (%s, exact=%s)",
+          koPos.percentage * 100, koPos.xpath.c_str(), result.spineIndex, result.pageNumber,
+          usedXPathMapping ? "xpath" : "percentage", xpathExactMatch ? "yes" : "no");

  return result;
 }

-std::string ProgressMapper::generateXPath(int spineIndex, int pageNumber, int totalPages) {
-  // Use 0-based DocFragment indices for KOReader
-  // Use a simple xpath pointing to the DocFragment - KOReader will use the percentage for fine positioning within it
-  // Avoid specifying paragraph numbers as they may not exist in the target document
-  return "/body/DocFragment[" + std::to_string(spineIndex) + "]/body";
+std::string ProgressMapper::generateXPath(int spineIndex) {
+  // Fallback path when element-level XPath extraction is unavailable.
+  // KOReader uses 1-based XPath predicates; spineIndex is 0-based internally.
+  return "/body/DocFragment[" + std::to_string(spineIndex + 1) + "]/body";
 }
--- a/lib/KOReaderSync/ProgressMapper.h
+++ b/lib/KOReaderSync/ProgressMapper.h
@@ -27,9 +27,16 @@ struct KOReaderPosition {
 * CrossPoint tracks position as (spineIndex, pageNumber).
 * KOReader uses XPath-like strings + percentage.
 *
- * Since CrossPoint discards HTML structure during parsing, we generate
- * synthetic XPath strings based on spine index, using percentage as the
- * primary sync mechanism.
+ * Forward mapping (CrossPoint -> KOReader):
+ * - Prefer element-level XPath extracted from current spine XHTML.
+ * - Fallback to synthetic chapter XPath if extraction fails.
+ *
+ * Reverse mapping (KOReader -> CrossPoint):
+ * - Prefer incoming XPath (DocFragment + element path) when resolvable.
+ * - Fallback to percentage-based approximation when XPath is missing/invalid.
+ *
+ * This keeps behavior stable on low-memory devices while improving round-trip
+ * sync precision when KOReader provides detailed paths.
 */
 class ProgressMapper {
 public:
@@ -45,8 +52,9 @@ class ProgressMapper {
  /**
   * Convert KOReader position to CrossPoint format.
   *
-   * Note: The returned pageNumber may be approximate since different
-   * rendering settings produce different page counts.
+   * Uses XPath-first resolution when possible and percentage fallback otherwise.
+   * Returned pageNumber can still be approximate because page counts differ
+   * across renderer/font/layout settings.
   *
   * @param epub The EPUB book
   * @param koPos KOReader position
@@ -60,8 +68,7 @@ class ProgressMapper {
 private:
  /**
   * Generate XPath for KOReader compatibility.
-   * Format: /body/DocFragment[spineIndex+1]/body
-   * Since CrossPoint doesn't preserve HTML structure, we rely on percentage for positioning.
+   * Fallback format: /body/DocFragment[spineIndex + 1]/body
   */
-  static std::string generateXPath(int spineIndex, int pageNumber, int totalPages);
+  static std::string generateXPath(int spineIndex);
 };
--- a/lib/hal/HalStorage.cpp
+++ b/lib/hal/HalStorage.cpp
@@ -137,6 +137,9 @@ void HalFile::flush() { HAL_FILE_WRAPPED_CALL(flush, ); }
 size_t HalFile::getName(char* name, size_t len) { HAL_FILE_WRAPPED_CALL(getName, name, len); }
 size_t HalFile::size() { HAL_FILE_FORWARD_CALL(size, ); }          // already thread-safe, no need to wrap
 size_t HalFile::fileSize() { HAL_FILE_FORWARD_CALL(fileSize, ); }  // already thread-safe, no need to wrap
+bool HalFile::getModifyDateTime(uint16_t* pdate, uint16_t* ptime) {
+  HAL_FILE_WRAPPED_CALL(getModifyDateTime, pdate, ptime);
+}
 bool HalFile::seek(size_t pos) { HAL_FILE_WRAPPED_CALL(seekSet, pos); }
 bool HalFile::seekCur(int64_t offset) { HAL_FILE_WRAPPED_CALL(seekCur, offset); }
 bool HalFile::seekSet(size_t offset) { HAL_FILE_WRAPPED_CALL(seekSet, offset); }
--- a/lib/hal/HalStorage.h
+++ b/lib/hal/HalStorage.h
@@ -76,6 +76,8 @@ class HalFile : public Print {
  size_t getName(char* name, size_t len);
  size_t size();
  size_t fileSize();
+  // Get modification date/time (FAT format: packed 16-bit date and time). Returns false if unavailable.
+  bool getModifyDateTime(uint16_t* pdate, uint16_t* ptime);
  bool seek(size_t pos);
  bool seekCur(int64_t offset);
  bool seekSet(size_t offset);
--- a/src/JsonSettingsIO.cpp
+++ b/src/JsonSettingsIO.cpp
@@ -213,44 +213,6 @@ bool JsonSettingsIO::loadSettings(CrossPointSettings& s, const char* json, bool*
  return true;
 }

-// ---- KOReaderCredentialStore ----
-
-bool JsonSettingsIO::saveKOReader(const KOReaderCredentialStore& store, const char* path) {
-  JsonDocument doc;
-  doc["username"] = store.getUsername();
-  doc["password_obf"] = obfuscation::obfuscateToBase64(store.getPassword());
-  doc["serverUrl"] = store.getServerUrl();
-  doc["matchMethod"] = static_cast<uint8_t>(store.getMatchMethod());
-
-  String json;
-  serializeJson(doc, json);
-  return Storage.writeFile(path, json);
-}
-
-bool JsonSettingsIO::loadKOReader(KOReaderCredentialStore& store, const char* json, bool* needsResave) {
-  if (needsResave) *needsResave = false;
-  JsonDocument doc;
-  auto error = deserializeJson(doc, json);
-  if (error) {
-    LOG_ERR("KRS", "JSON parse error: %s", error.c_str());
-    return false;
-  }
-
-  store.username = doc["username"] | std::string("");
-  bool ok = false;
-  store.password = obfuscation::deobfuscateFromBase64(doc["password_obf"] | "", &ok);
-  if (!ok || store.password.empty()) {
-    store.password = doc["password"] | std::string("");
-    if (!store.password.empty() && needsResave) *needsResave = true;
-  }
-  store.serverUrl = doc["serverUrl"] | std::string("");
-  uint8_t method = doc["matchMethod"] | (uint8_t)0;
-  store.matchMethod = static_cast<DocumentMatchMethod>(method);
-
-  LOG_DBG("KRS", "Loaded KOReader credentials for user: %s", store.username.c_str());
-  return true;
-}
-
 // ---- WifiCredentialStore ----

 bool JsonSettingsIO::saveWifi(const WifiCredentialStore& store, const char* path) {
--- a/src/JsonSettingsIO.h
+++ b/src/JsonSettingsIO.h
@@ -3,7 +3,6 @@
 class CrossPointSettings;
 class CrossPointState;
 class WifiCredentialStore;
-class KOReaderCredentialStore;
 class RecentBooksStore;

 namespace JsonSettingsIO {
@@ -20,10 +19,6 @@ bool loadState(CrossPointState& s, const char* json);
 bool saveWifi(const WifiCredentialStore& store, const char* path);
 bool loadWifi(WifiCredentialStore& store, const char* json, bool* needsResave = nullptr);

-// KOReaderCredentialStore
-bool saveKOReader(const KOReaderCredentialStore& store, const char* path);
-bool loadKOReader(KOReaderCredentialStore& store, const char* json, bool* needsResave = nullptr);
-
 // RecentBooksStore
 bool saveRecentBooks(const RecentBooksStore& store, const char* path);
 bool loadRecentBooks(RecentBooksStore& store, const char* json);
--- a/src/activities/ActivityManager.cpp
+++ b/src/activities/ActivityManager.cpp
@@ -181,6 +181,10 @@ void ActivityManager::goToBrowser() {
  replaceActivity(std::make_unique<OpdsBookBrowserActivity>(renderer, mappedInput));
 }

+void ActivityManager::goToBrowser(const OpdsServer& server) {
+  replaceActivity(std::make_unique<OpdsBookBrowserActivity>(renderer, mappedInput, &server));
+}
+
 void ActivityManager::goToReader(std::string path) {
  replaceActivity(std::make_unique<ReaderActivity>(renderer, mappedInput, std::move(path)));
 }
--- a/src/activities/ActivityManager.h
+++ b/src/activities/ActivityManager.h
@@ -11,6 +11,7 @@

 #include "GfxRenderer.h"
 #include "MappedInputManager.h"
+#include "OpdsServerStore.h"

 class Activity;    // forward declaration
 class RenderLock;  // forward declaration
@@ -82,6 +83,7 @@ class ActivityManager {
  void goToFileBrowser(std::string path = {});
  void goToRecentBooks();
  void goToBrowser();
+  void goToBrowser(const struct OpdsServer& server);
  void goToReader(std::string path);
  void goToSleep();
  void goToBoot();
--- a/src/activities/browser/OpdsBookBrowserActivity.cpp
+++ b/src/activities/browser/OpdsBookBrowserActivity.cpp
@@ -7,9 +7,11 @@
 #include <OpdsStream.h>
 #include <WiFi.h>

-#include "CrossPointSettings.h"
+#include "activities/ActivityResult.h"
 #include "MappedInputManager.h"
+#include "OpdsServerStore.h"
 #include "activities/network/WifiSelectionActivity.h"
+#include "activities/util/DirectoryPickerActivity.h"
 #include "components/UITheme.h"
 #include "fontIds.h"
 #include "network/HttpDownloader.h"
@@ -23,16 +25,22 @@ constexpr int PAGE_ITEMS = 23;
 void OpdsBookBrowserActivity::onEnter() {
  Activity::onEnter();

+  OPDS_STORE.loadFromFile();
+  // Resolve server from store if not provided at construction
+  if (server.url.empty() && OPDS_STORE.hasServers()) {
+    const auto* s = OPDS_STORE.getServer(0);
+    if (s) server = *s;
+  }
+
  state = BrowserState::CHECK_WIFI;
  entries.clear();
  navigationHistory.clear();
-  currentPath = "";  // Root path - user provides full URL in settings
+  currentPath = "";
  selectorIndex = 0;
  errorMessage.clear();
  statusMessage = tr(STR_CHECKING_WIFI);
  requestUpdate();

-  // Check WiFi and connect if needed, then fetch feed
  checkAndConnectWifi();
 }

@@ -47,9 +55,7 @@ void OpdsBookBrowserActivity::onExit() {
 }

 void OpdsBookBrowserActivity::loop() {
-  // Handle WiFi selection subactivity
-  if (state == BrowserState::WIFI_SELECTION) {
-    // Should already handled by the WifiSelectionActivity
+  if (state == BrowserState::WIFI_SELECTION || state == BrowserState::PICKING_DIRECTORY) {
    return;
  }

@@ -91,18 +97,40 @@ void OpdsBookBrowserActivity::loop() {
    return;
  }

-  // Handle downloading state - no input allowed
  if (state == BrowserState::DOWNLOADING) {
    return;
  }

-  // Handle browsing state
+  if (state == BrowserState::DOWNLOAD_COMPLETE) {
+    if (mappedInput.wasReleased(MappedInputManager::Button::Back)) {
+      executePromptAction(0);
+      return;
+    }
+    if (mappedInput.wasReleased(MappedInputManager::Button::Confirm)) {
+      executePromptAction(promptSelection);
+      return;
+    }
+    buttonNavigator.onNextRelease([this] {
+      if (promptSelection != 1) {
+        promptSelection = 1;
+        requestUpdate();
+      }
+    });
+    buttonNavigator.onPreviousRelease([this] {
+      if (promptSelection != 0) {
+        promptSelection = 0;
+        requestUpdate();
+      }
+    });
+    return;
+  }
+
  if (state == BrowserState::BROWSING) {
    if (mappedInput.wasReleased(MappedInputManager::Button::Confirm)) {
      if (!entries.empty()) {
        const auto& entry = entries[selectorIndex];
        if (entry.type == OpdsEntryType::BOOK) {
-          downloadBook(entry);
+          launchDirectoryPicker(entry);
        } else {
          navigateToEntry(entry);
        }
@@ -142,7 +170,8 @@ void OpdsBookBrowserActivity::render(RenderLock&&) {
  const auto pageWidth = renderer.getScreenWidth();
  const auto pageHeight = renderer.getScreenHeight();

-  renderer.drawCenteredText(UI_12_FONT_ID, 15, tr(STR_OPDS_BROWSER), true, EpdFontFamily::BOLD);
+  const char* headerTitle = server.name.empty() ? tr(STR_OPDS_BROWSER) : server.name.c_str();
+  renderer.drawCenteredText(UI_12_FONT_ID, 15, headerTitle, true, EpdFontFamily::BOLD);

  if (state == BrowserState::CHECK_WIFI) {
    renderer.drawCenteredText(UI_10_FONT_ID, pageHeight / 2, statusMessage.c_str());
@@ -186,6 +215,31 @@ void OpdsBookBrowserActivity::render(RenderLock&&) {
    return;
  }

+  if (state == BrowserState::DOWNLOAD_COMPLETE) {
+    renderer.drawCenteredText(UI_12_FONT_ID, pageHeight / 2 - 50, tr(STR_DOWNLOAD_COMPLETE), true, EpdFontFamily::BOLD);
+    const auto maxWidth = pageWidth - 40;
+    auto title = renderer.truncatedText(UI_10_FONT_ID, statusMessage.c_str(), maxWidth);
+    renderer.drawCenteredText(UI_10_FONT_ID, pageHeight / 2 - 20, title.c_str());
+
+    const int buttonY = pageHeight / 2 + 20;
+    const char* backText = tr(STR_BACK_TO_LISTING);
+    const char* openText = tr(STR_OPEN_BOOK);
+    std::string backLabel = promptSelection == 0 ? "[" + std::string(backText) + "]" : std::string(backText);
+    std::string openLabel = promptSelection == 1 ? "[" + std::string(openText) + "]" : std::string(openText);
+    const int backWidth = renderer.getTextWidth(UI_10_FONT_ID, backLabel.c_str());
+    const int openWidth = renderer.getTextWidth(UI_10_FONT_ID, openLabel.c_str());
+    constexpr int buttonSpacing = 40;
+    const int totalWidth = backWidth + buttonSpacing + openWidth;
+    const int startX = (pageWidth - totalWidth) / 2;
+    renderer.drawText(UI_10_FONT_ID, startX, buttonY, backLabel.c_str());
+    renderer.drawText(UI_10_FONT_ID, startX + backWidth + buttonSpacing, buttonY, openLabel.c_str());
+
+    const auto labels = mappedInput.mapLabels(tr(STR_BACK), tr(STR_CONFIRM), tr(STR_DIR_LEFT), tr(STR_DIR_RIGHT));
+    GUI.drawButtonHints(renderer, labels.btn1, labels.btn2, labels.btn3, labels.btn4);
+    renderer.displayBuffer();
+    return;
+  }
+
  // Browsing state
  // Show appropriate button hint based on selected entry type
  const char* confirmLabel = tr(STR_OPEN);
@@ -228,22 +282,21 @@ void OpdsBookBrowserActivity::render(RenderLock&&) {
 }

 void OpdsBookBrowserActivity::fetchFeed(const std::string& path) {
-  const char* serverUrl = SETTINGS.opdsServerUrl;
-  if (strlen(serverUrl) == 0) {
+  if (server.url.empty()) {
    state = BrowserState::ERROR;
    errorMessage = tr(STR_NO_SERVER_URL);
    requestUpdate();
    return;
  }

-  std::string url = UrlUtils::buildUrl(serverUrl, path);
+  std::string url = UrlUtils::buildUrl(server.url, path);
  LOG_DBG("OPDS", "Fetching: %s", url.c_str());

  OpdsParser parser;

  {
    OpdsParserStream stream{parser};
-    if (!HttpDownloader::fetchUrl(url, stream)) {
+    if (!HttpDownloader::fetchUrl(url, stream, server.username, server.password)) {
      state = BrowserState::ERROR;
      errorMessage = tr(STR_FETCH_FEED_FAILED);
      requestUpdate();
@@ -306,41 +359,68 @@ void OpdsBookBrowserActivity::navigateBack() {
  }
 }

-void OpdsBookBrowserActivity::downloadBook(const OpdsEntry& book) {
+void OpdsBookBrowserActivity::launchDirectoryPicker(const OpdsEntry& book) {
+  pendingBook = book;
+  state = BrowserState::PICKING_DIRECTORY;
+  requestUpdate();
+
+  startActivityForResult(
+      std::make_unique<DirectoryPickerActivity>(renderer, mappedInput, server.downloadPath),
+      [this](const ActivityResult& result) { onDirectoryPickerResult(result); });
+}
+
+void OpdsBookBrowserActivity::onDirectoryPickerResult(const ActivityResult& result) {
+  state = BrowserState::BROWSING;
+  if (result.isCancelled) {
+    requestUpdate();
+    return;
+  }
+  if (std::holds_alternative<KeyboardResult>(result.data)) {
+    const std::string& directory = std::get<KeyboardResult>(result.data).text;
+    downloadBook(pendingBook, directory);
+  } else {
+    requestUpdate();
+  }
+}
+
+void OpdsBookBrowserActivity::downloadBook(const OpdsEntry& book, const std::string& directory) {
  state = BrowserState::DOWNLOADING;
  statusMessage = book.title;
  downloadProgress = 0;
  downloadTotal = 0;
  requestUpdate(true);

-  // Build full download URL
-  std::string downloadUrl = UrlUtils::buildUrl(SETTINGS.opdsServerUrl, book.href);
+  std::string downloadUrl = UrlUtils::buildUrl(server.url, book.href);

-  // Create sanitized filename: "Title - Author.epub" or just "Title.epub" if no author
  std::string baseName = book.title;
  if (!book.author.empty()) {
    baseName += " - " + book.author;
  }
-  std::string filename = "/" + StringUtils::sanitizeFilename(baseName) + ".epub";
+  std::string dir = directory;
+  if (dir.back() != '/') dir += '/';
+  std::string filename = dir + StringUtils::sanitizeFilename(baseName) + ".epub";

  LOG_DBG("OPDS", "Downloading: %s -> %s", downloadUrl.c_str(), filename.c_str());

-  const auto result =
-      HttpDownloader::downloadToFile(downloadUrl, filename, [this](const size_t downloaded, const size_t total) {
+  const auto result = HttpDownloader::downloadToFile(
+      downloadUrl, filename,
+      [this](const size_t downloaded, const size_t total) {
        downloadProgress = downloaded;
        downloadTotal = total;
-        requestUpdate(true);  // Force update to refresh progress bar
-      });
+        requestUpdate(true);
+      },
+      server.username, server.password);

  if (result == HttpDownloader::OK) {
    LOG_DBG("OPDS", "Download complete: %s", filename.c_str());

-    // Invalidate any existing cache for this file to prevent stale metadata issues
    Epub epub(filename, "/.crosspoint");
    epub.clearCache();
    LOG_DBG("OPDS", "Cleared cache for: %s", filename.c_str());

-    state = BrowserState::BROWSING;
+    downloadedFilePath = filename;
+    promptSelection = server.afterDownloadAction;
+    state = BrowserState::DOWNLOAD_COMPLETE;
    requestUpdate();
  } else {
    state = BrowserState::ERROR;
@@ -349,6 +429,15 @@ void OpdsBookBrowserActivity::downloadBook(const OpdsEntry& book) {
  }
 }

+void OpdsBookBrowserActivity::executePromptAction(int action) {
+  if (action == 1) {
+    onSelectBook(downloadedFilePath);
+    return;
+  }
+  state = BrowserState::BROWSING;
+  requestUpdate();
+}
+
 void OpdsBookBrowserActivity::checkAndConnectWifi() {
  // Already connected? Verify connection is valid by checking IP
  if (WiFi.status() == WL_CONNECTED && WiFi.localIP() != IPAddress(0, 0, 0, 0)) {
--- a/src/activities/browser/OpdsBookBrowserActivity.h
+++ b/src/activities/browser/OpdsBookBrowserActivity.h
@@ -6,6 +6,7 @@
 #include <vector>

 #include "../Activity.h"
+#include "OpdsServerStore.h"
 #include "util/ButtonNavigator.h"

 /**
@@ -16,16 +17,19 @@
 class OpdsBookBrowserActivity final : public Activity {
 public:
  enum class BrowserState {
-    CHECK_WIFI,      // Checking WiFi connection
-    WIFI_SELECTION,  // WiFi selection subactivity is active
-    LOADING,         // Fetching OPDS feed
-    BROWSING,        // Displaying entries (navigation or books)
-    DOWNLOADING,     // Downloading selected EPUB
-    ERROR            // Error state with message
+    CHECK_WIFI,        // Checking WiFi connection
+    WIFI_SELECTION,    // WiFi selection subactivity is active
+    LOADING,           // Fetching OPDS feed
+    BROWSING,          // Displaying entries (navigation or books)
+    PICKING_DIRECTORY, // Directory picker subactivity is active
+    DOWNLOADING,       // Downloading selected EPUB
+    DOWNLOAD_COMPLETE, // Prompt: open book or go back to listing
+    ERROR              // Error state with message
  };

-  explicit OpdsBookBrowserActivity(GfxRenderer& renderer, MappedInputManager& mappedInput)
-      : Activity("OpdsBookBrowser", renderer, mappedInput) {}
+  explicit OpdsBookBrowserActivity(GfxRenderer& renderer, MappedInputManager& mappedInput,
+                                  const OpdsServer* server = nullptr)
+      : Activity("OpdsBookBrowser", renderer, mappedInput), server(server ? *server : OpdsServer{}) {}

  void onEnter() override;
  void onExit() override;
@@ -43,6 +47,11 @@ class OpdsBookBrowserActivity final : public Activity {
  std::string statusMessage;
  size_t downloadProgress = 0;
  size_t downloadTotal = 0;
+  std::string downloadedFilePath;
+  int promptSelection = 0;  // 0 = back to listing, 1 = open book
+
+  OpdsServer server;  // Copied at construction — safe even if the store changes during browsing
+  OpdsEntry pendingBook;

  void checkAndConnectWifi();
  void launchWifiSelection();
@@ -50,6 +59,9 @@ class OpdsBookBrowserActivity final : public Activity {
  void fetchFeed(const std::string& path);
  void navigateToEntry(const OpdsEntry& entry);
  void navigateBack();
-  void downloadBook(const OpdsEntry& book);
+  void launchDirectoryPicker(const OpdsEntry& book);
+  void onDirectoryPickerResult(const ActivityResult& result);
+  void downloadBook(const OpdsEntry& book, const std::string& directory);
+  void executePromptAction(int action);
  bool preventAutoSleep() override { return true; }
 };
--- a/src/activities/home/BookManageMenuActivity.cpp
+++ b/src/activities/home/BookManageMenuActivity.cpp
@@ -3,7 +3,7 @@
 #include <GfxRenderer.h>
 #include <I18n.h>

-#include "ActivityResult.h"
+#include "activities/ActivityResult.h"
 #include "MappedInputManager.h"
 #include "components/UITheme.h"
 #include "fontIds.h"
--- a/src/activities/home/FileBrowserActivity.cpp
+++ b/src/activities/home/FileBrowserActivity.cpp
@@ -244,6 +244,15 @@ std::string getFileName(std::string filename) {
  return filename.substr(0, pos);
 }

+std::string getFileExtension(std::string filename) {
+  if (filename.back() == '/') {
+    return "";
+  }
+  const auto pos = filename.rfind('.');
+  if (pos == std::string::npos) return "";
+  return filename.substr(pos);
+}
+
 void FileBrowserActivity::render(RenderLock&&) {
  renderer.clearScreen();

@@ -262,7 +271,8 @@ void FileBrowserActivity::render(RenderLock&&) {
    GUI.drawList(
        renderer, Rect{0, contentTop, pageWidth, contentHeight}, files.size(), selectorIndex,
        [this](int index) { return getFileName(files[index]); }, nullptr,
-        [this](int index) { return UITheme::getFileIcon(files[index]); });
+        [this](int index) { return UITheme::getFileIcon(files[index]); },
+        [this](int index) { return getFileExtension(files[index]); }, false);
  }

  // Help text
--- a/src/activities/home/HomeActivity.cpp
+++ b/src/activities/home/HomeActivity.cpp
@@ -24,7 +24,7 @@
 #include "components/UITheme.h"
 #include "fontIds.h"
 #include "util/BookManager.h"
-#include "util/StringUtils.h"
+

 int HomeActivity::getMenuItemCount() const {
  int count = 4;  // File Browser, Recents, File transfer, Settings
@@ -66,7 +66,7 @@ void HomeActivity::loadRecentCovers(int coverHeight) {
  for (RecentBook& book : recentBooks) {
    if (!book.coverBmpPath.empty()) {
      std::string coverPath = UITheme::getCoverThumbPath(book.coverBmpPath, coverHeight);
-      if (!Epub::isValidThumbnailBmp(coverPath)) {
+      if (!Storage.exists(coverPath.c_str())) {
        if (!showingLoading) {
          showingLoading = true;
          popupRect = GUI.drawPopup(renderer, tr(STR_LOADING));
@@ -75,7 +75,7 @@ void HomeActivity::loadRecentCovers(int coverHeight) {

        bool success = false;

-        if (StringUtils::checkFileExtension(book.path, ".epub")) {
+        if (FsHelpers::hasEpubExtension(book.path)) {
          Epub epub(book.path, "/.crosspoint");
          if (!epub.load(false, true)) {
            epub.load(true, true);
@@ -87,13 +87,9 @@ void HomeActivity::loadRecentCovers(int coverHeight) {
            book.coverBmpPath = thumbPath;
          } else {
            const int thumbWidth = static_cast<int>(coverHeight * 0.6);
-            success = PlaceholderCoverGenerator::generate(coverPath, book.title, book.author, thumbWidth, coverHeight);
-            if (!success) {
-              epub.generateInvalidFormatThumbBmp(coverHeight);
-            }
+            PlaceholderCoverGenerator::generate(coverPath, book.title, book.author, thumbWidth, coverHeight);
          }
-        } else if (StringUtils::checkFileExtension(book.path, ".xtch") ||
-                   StringUtils::checkFileExtension(book.path, ".xtc")) {
+        } else if (FsHelpers::hasXtcExtension(book.path)) {
          Xtc xtc(book.path, "/.crosspoint");
          if (xtc.load()) {
            success = xtc.generateThumbBmp(coverHeight);
--- a/src/network/HttpDownloader.cpp
+++ b/src/network/HttpDownloader.cpp
@@ -52,8 +52,24 @@ class FileWriteStream final : public Stream {
 };
 }  // namespace

+static void addAuthHeader(HTTPClient& http, const std::string& username, const std::string& password) {
+  if (!username.empty() || !password.empty()) {
+    std::string credentials = username + ":" + password;
+    String encoded = base64::encode(credentials.c_str());
+    http.addHeader("Authorization", "Basic " + encoded);
+  } else if (strlen(SETTINGS.opdsUsername) > 0 && strlen(SETTINGS.opdsPassword) > 0) {
+    std::string credentials = std::string(SETTINGS.opdsUsername) + ":" + SETTINGS.opdsPassword;
+    String encoded = base64::encode(credentials.c_str());
+    http.addHeader("Authorization", "Basic " + encoded);
+  }
+}
+
 bool HttpDownloader::fetchUrl(const std::string& url, Stream& outContent) {
-  // Use NetworkClientSecure for HTTPS, regular NetworkClient for HTTP
+  return fetchUrl(url, outContent, "", "");
+}
+
+bool HttpDownloader::fetchUrl(const std::string& url, Stream& outContent, const std::string& username,
+                              const std::string& password) {
  std::unique_ptr<NetworkClient> client;
  if (UrlUtils::isHttpsUrl(url)) {
    auto* secureClient = new NetworkClientSecure();
@@ -69,13 +85,7 @@ bool HttpDownloader::fetchUrl(const std::string& url, Stream& outContent) {
  http.begin(*client, url.c_str());
  http.setFollowRedirects(HTTPC_STRICT_FOLLOW_REDIRECTS);
  http.addHeader("User-Agent", "CrossPoint-ESP32-" CROSSPOINT_VERSION);
-
-  // Add Basic HTTP auth if credentials are configured
-  if (strlen(SETTINGS.opdsUsername) > 0 && strlen(SETTINGS.opdsPassword) > 0) {
-    std::string credentials = std::string(SETTINGS.opdsUsername) + ":" + SETTINGS.opdsPassword;
-    String encoded = base64::encode(credentials.c_str());
-    http.addHeader("Authorization", "Basic " + encoded);
-  }
+  addAuthHeader(http, username, password);

  const int httpCode = http.GET();
  if (httpCode != HTTP_CODE_OK) {
@@ -85,7 +95,6 @@ bool HttpDownloader::fetchUrl(const std::string& url, Stream& outContent) {
  }

  http.writeToStream(&outContent);
-
  http.end();

  LOG_DBG("HTTP", "Fetch success");
@@ -103,7 +112,12 @@ bool HttpDownloader::fetchUrl(const std::string& url, std::string& outContent) {

 HttpDownloader::DownloadError HttpDownloader::downloadToFile(const std::string& url, const std::string& destPath,
                                                             ProgressCallback progress) {
-  // Use NetworkClientSecure for HTTPS, regular NetworkClient for HTTP
+  return downloadToFile(url, destPath, progress, "", "");
+}
+
+HttpDownloader::DownloadError HttpDownloader::downloadToFile(const std::string& url, const std::string& destPath,
+                                                           ProgressCallback progress, const std::string& username,
+                                                           const std::string& password) {
  std::unique_ptr<NetworkClient> client;
  if (UrlUtils::isHttpsUrl(url)) {
    auto* secureClient = new NetworkClientSecure();
@@ -120,13 +134,7 @@ HttpDownloader::DownloadError HttpDownloader::downloadToFile(const std::string&
  http.begin(*client, url.c_str());
  http.setFollowRedirects(HTTPC_STRICT_FOLLOW_REDIRECTS);
  http.addHeader("User-Agent", "CrossPoint-ESP32-" CROSSPOINT_VERSION);
-
-  // Add Basic HTTP auth if credentials are configured
-  if (strlen(SETTINGS.opdsUsername) > 0 && strlen(SETTINGS.opdsPassword) > 0) {
-    std::string credentials = std::string(SETTINGS.opdsUsername) + ":" + SETTINGS.opdsPassword;
-    String encoded = base64::encode(credentials.c_str());
-    http.addHeader("Authorization", "Basic " + encoded);
-  }
+  addAuthHeader(http, username, password);

  const int httpCode = http.GET();
  if (httpCode != HTTP_CODE_OK) {
--- a/src/network/HttpDownloader.h
+++ b/src/network/HttpDownloader.h
@@ -29,6 +29,13 @@ class HttpDownloader {

  static bool fetchUrl(const std::string& url, Stream& stream);

+  /**
+   * Fetch URL with optional HTTP Basic auth credentials.
+   * When username and password are empty, falls back to CrossPointSettings credentials.
+   */
+  static bool fetchUrl(const std::string& url, Stream& stream, const std::string& username,
+                      const std::string& password);
+
  /**
   * Download a file to the SD card.
   * @param url The URL to download
@@ -38,4 +45,12 @@ class HttpDownloader {
   */
  static DownloadError downloadToFile(const std::string& url, const std::string& destPath,
                                      ProgressCallback progress = nullptr);
+
+  /**
+   * Download a file with optional HTTP Basic auth credentials.
+   * When username and password are empty, falls back to CrossPointSettings credentials.
+   */
+  static DownloadError downloadToFile(const std::string& url, const std::string& destPath,
+                                     ProgressCallback progress, const std::string& username,
+                                     const std::string& password);
 };