Add SD catalog as default EPUB container backend

Changes the container backend strategy to use SD catalog by default for all EPUBs. On first open or stale index, builds the catalog once by borrowing the framebuffer (which can be released since e-ink holds the loading popup image). Subsequent opens use the fast path with compact resident tables. Falls back to legacy in-RAM open if catalog build fails due to IoError or OOM.

README.md

@@ -8,6 +8,8 @@ CrossPoint is open-source e-reader firmware - community-built, fully hackable, f
 
 ![CrossPoint Reader running on Xteink device](./docs/images/cover.jpg)
 
+> If you're planning to buy an Xteink device, consider purchasing an **X3/X4 Developer Edition** through https://crosspointreader.com. CrossPoint receives a small share of each sale, helping fund development costs.
+
 ## What can CrossPoint do?
 
 - **Reader engine**: EPUB 2/3 rendering with embedded-style option, image handling, hyphenation, kerning, chapter navigation, footnotes, bookmarks, go-to-percent, auto page turn, orientation control, focus reading, KOReader progress sync and more. 
@@ -67,10 +69,6 @@ USB port or browser before assuming the device is locked. Only reach for the unl
 > Flashing any other firmware on a USB-locked device may **permanently brick the device** or leave it **permanently
 > stuck on that firmware with no recovery path**. Once USB flashing is re-locked, your only way back is via OTA, and if
 > the firmware you flashed doesn't support OTA, **there is no way out**.
-> 
-> **The Papyrix fork has removed OTA update support from its code.** If you flash Papyrix onto a
-> USB-locked unit, you will have **zero update or recovery path** and will be stuck on it forever. **Do not flash
-> Papyrix (or any other unsupported firmware) on a locked device.**
 
 ## Install firmware
 
@@ -249,7 +247,7 @@ One of the best things about open source is that anyone can take the code in a d
 
 - [papyrix-reader](https://github.com/bigbag/papyrix-reader) — Adds FB2 and MD format support. Actively maintained with Arabic script support. Custom themes via SD card.
 
-- [crosspet](https://github.com/trilwu/crosspet) — A Vietnamese fork that adds a Tamagotchi-style virtual chicken that grows based on your reading milestones (pages read, streaks, care). Also: Flashcards, Weather, Pomodoro timer, and mini-games.
+- ~~[crosspet](https://github.com/trilwu/crosspet) — A Vietnamese fork that adds a Tamagotchi-style virtual chicken that grows based on your reading milestones (pages read, streaks, care). Also: Flashcards, Weather, Pomodoro timer, and mini-games.~~ (Unmaintained)
 
 - [crosspoint-reader-cjk](https://github.com/aBER0724/crosspoint-reader-cjk) — Purpose-built for Chinese, Japanese, and Korean reading.
 

USER_GUIDE.md

@@ -5,6 +5,7 @@ Welcome to the **CrossPoint** firmware. This guide outlines the hardware control
 - [CrossPoint User Guide](#crosspoint-user-guide)
   - [1. Hardware Overview](#1-hardware-overview)
     - [Button Layout](#button-layout)
+    - [Taking a Screenshot](#taking-a-screenshot)
   - [2. Power \& Startup](#2-power--startup)
     - [Power On / Off](#power-on--off)
     - [First Launch](#first-launch)
@@ -14,7 +15,11 @@ Welcome to the **CrossPoint** firmware. This guide outlines the hardware control
     - [3.3 Browse Files Screen](#33-browse-files-screen)
     - [3.4 Recent Books Screen](#34-recent-books-screen)
     - [3.5 File Transfer Screen](#35-file-transfer-screen)
-      - [3.5.1 Calibre Wireless Transfers](#351-calibre-wireless-transfers)
+    - [3.5.1 Calibre Wireless Transfers](#351-calibre-wireless-transfers)
+      - [Installing the Plugin in Calibre](#installing-the-plugin-in-calibre)
+      - [Configuring the CrossPoint Plugin in Calibre](#configuring-the-crosspoint-plugin-in-calibre)
+      - [Uploading Books](#uploading-books)
+      - [Removing a Book](#removing-a-book)
     - [3.6 Settings](#36-settings)
       - [3.6.1 Display](#361-display)
       - [3.6.2 Reader](#362-reader)
@@ -23,21 +28,25 @@ Welcome to the **CrossPoint** firmware. This guide outlines the hardware control
       - [3.6.5 OPDS Servers (Multiple Libraries)](#365-opds-servers-multiple-libraries)
       - [3.6.6 Web Settings (Wi-Fi + OPDS)](#366-web-settings-wi-fi--opds)
       - [3.6.7 KOReader Sync Quick Setup](#367-koreader-sync-quick-setup)
+        - [Option A: Free Public Server (`sync.koreader.rocks`)](#option-a-free-public-server-synckoreaderrocks)
+        - [Option B: Self-Hosted Server (Docker Compose)](#option-b-self-hosted-server-docker-compose)
     - [3.7 Sleep Screen](#37-sleep-screen)
+      - [Cover settings](#cover-settings)
+      - [Custom images](#custom-images)
     - [3.8 Custom Fonts (SD Card)](#38-custom-fonts-sd-card)
   - [4. Reading Mode](#4-reading-mode)
-      - [Page Turning](#page-turning)
-      - [Chapter Navigation](#chapter-navigation)
-      - [Auto Page Turn](#auto-page-turn)
-      - [Tilt Page Turn (X3 only)](#tilt-page-turn-x3-only)
-      - [Footnote Navigation](#footnote-navigation)
-      - [System Navigation](#system-navigation)
-      - [Supported Languages](#supported-languages)
+    - [Page Turning](#page-turning)
+    - [Chapter Navigation](#chapter-navigation)
+    - [Auto Page Turn](#auto-page-turn)
+    - [Tilt Page Turn (X3 only)](#tilt-page-turn-x3-only)
+    - [Footnote Navigation](#footnote-navigation)
+    - [System Navigation](#system-navigation)
+    - [Supported Languages](#supported-languages)
   - [5. Reader Menu](#5-reader-menu)
-      - [5.1 Chapter Selection](#51-chapter-selection)
-      - [5.2 Bookmarks](#52-bookmarks)
-  - [6. Current Limitations & Roadmap](#6-current-limitations--roadmap)
-  - [7. Troubleshooting Issues & Escaping Bootloop](#7-troubleshooting-issues--escaping-bootloop)
+    - [5.1 Chapter Selection](#51-chapter-selection)
+    - [5.2 Bookmarks](#52-bookmarks)
+  - [6. Current Limitations \& Roadmap](#6-current-limitations--roadmap)
+  - [7. Troubleshooting Issues \& Escaping Bootloop](#7-troubleshooting-issues--escaping-bootloop)
 
 ## 1. Hardware Overview
 

docs/file-formats.md

@@ -90,13 +90,13 @@ if (parsedSize != fileSize) {
 
 ## `section.bin`
 
-### Version 25
+### Version 29
 
 Each file in `sections/*.bin` stores one laid-out spine section. The header is
 also the cache-busting key: if any layout-affecting setting differs from the
 current reader settings, the section is discarded and rebuilt.
 
-Version 25 includes:
+Version 29 includes:
 
 - cache-busting fields for paragraph alignment, hyphenation, embedded CSS,
   image rendering mode, and Focus Reading
@@ -105,6 +105,12 @@ Version 25 includes:
 - paragraph and list-item LUTs used by KOReader sync page refinement
 - optional per-word Focus Reading split metadata
 - per-page footnote entries
+- serialized word style bits for underline, strikethrough, superscript, and
+  subscript
+- flat TextBlock word storage (v29): per-word arrays plus one shared
+  NUL-terminated text blob, replacing v28's length-prefixed word strings. The
+  on-disk order mirrors the in-RAM arena so the firmware reads a whole block
+  payload with a single allocation and a single SD read
 
 ImHex pattern:
 
@@ -113,7 +119,7 @@ import std.mem;
 import std.string;
 import std.core;
 
-#define EXPECTED_VERSION 25
+#define EXPECTED_VERSION 29
 #define MAX_STRING_LENGTH 65535
 #define FOOTNOTE_NUMBER_LEN 32
 #define FOOTNOTE_HREF_LEN 96
@@ -174,14 +180,20 @@ struct BlockStyle {
 
 struct TextBlock {
     u16 wordCount;
-    String words[wordCount];
-    s16 wordXPos[wordCount];
-    WordStyle wordStyle[wordCount];
-
     u8 hasFocus;
-    if (hasFocus != 0) {
-        u8 wordFocusBoundary[wordCount] [[comment("UTF-8 byte boundary between bold prefix and suffix")]];
-        u16 wordFocusSuffixX[wordCount] [[comment("Suffix x offset from word start")]];
+    u16 textBytes [[comment("Total size of text[], including one NUL per word")]];
+
+    if (wordCount > 0) {
+        u16 textOff[wordCount] [[comment("Byte offset of word i's text within text[]")]];
+        s16 wordXPos[wordCount];
+        if (hasFocus != 0) {
+            u16 wordFocusSuffixX[wordCount] [[comment("Suffix x offset from word start")]];
+        }
+        WordStyle wordStyle[wordCount];
+        if (hasFocus != 0) {
+            u8 wordFocusBoundary[wordCount] [[comment("UTF-8 byte boundary between bold prefix and suffix")]];
+        }
+        char text[textBytes] [[comment("All words back to back, each NUL-terminated")]];
     }
 
     BlockStyle blockStyle;

lib/EpdFont/EpdFont.cpp

@@ -154,6 +154,21 @@ uint32_t EpdFont::applyLigatures(uint32_t cp, const char*& text) const {
   return cp;
 }
 
+bool EpdFont::hasGlyph(const uint32_t cp) const {
+  const int count = data->intervalCount;
+  if (count > 0) {
+    const EpdUnicodeInterval* intervals = data->intervals;
+    const auto it =
+        std::upper_bound(intervals, intervals + count, cp,
+                         [](uint32_t value, const EpdUnicodeInterval& interval) { return value < interval.first; });
+    if (it != intervals && cp <= (it - 1)->last) return true;
+  }
+  if (data->glyphMissHandler) {
+    return data->glyphMissHandler(data->glyphMissCtx, cp) != nullptr;
+  }
+  return false;
+}
+
 const EpdGlyph* EpdFont::getGlyph(const uint32_t cp) const {
   const int count = data->intervalCount;
   if (count == 0 && !data->glyphMissHandler) return nullptr;

lib/EpdFont/EpdFont.h

@@ -12,6 +12,12 @@ class EpdFont {
 
   const EpdGlyph* getGlyph(uint32_t cp) const;
 
+  /// True when the font actually provides `cp` (interval table or on-demand
+  /// SD load) — unlike getGlyph(), never satisfied by the replacement glyph.
+  /// Used by layout shaping to decide whether a substitution (ligature,
+  /// Arabic presentation form) can really be drawn.
+  bool hasGlyph(uint32_t cp) const;
+
   /// Returns the kerning adjustment (4.4 fixed-point in pixels) between two codepoints.
   /// Returns 0 if no kerning data exists for the pair.
   int8_t getKerning(uint32_t leftCp, uint32_t rightCp) const;

lib/EpdFont/EpdFontFamily.cpp

@@ -1,7 +1,7 @@
 #include "EpdFontFamily.h"
 
 const EpdFont* EpdFontFamily::getFont(const Style style) const {
-  // Extract font style bits (ignore UNDERLINE bit for font selection)
+  // Extract font style bits; render-time overlay bits do not affect font selection.
   const bool hasBold = (style & BOLD) != 0;
   const bool hasItalic = (style & ITALIC) != 0;
 
@@ -28,10 +28,16 @@ const EpdGlyph* EpdFontFamily::getGlyph(const uint32_t cp, const Style style) co
   return getFont(style)->getGlyph(cp);
 }
 
+bool EpdFontFamily::hasGlyph(const uint32_t cp, const Style style) const { return getFont(style)->hasGlyph(cp); }
+
 int8_t EpdFontFamily::getKerning(const uint32_t leftCp, const uint32_t rightCp, const Style style) const {
   return getFont(style)->getKerning(leftCp, rightCp);
 }
 
+uint32_t EpdFontFamily::getLigature(const uint32_t leftCp, const uint32_t rightCp, const Style style) const {
+  return getFont(style)->getLigature(leftCp, rightCp);
+}
+
 uint32_t EpdFontFamily::applyLigatures(const uint32_t cp, const char*& text, const Style style) const {
   return getFont(style)->applyLigatures(cp, text);
 }

lib/EpdFont/EpdFontFamily.h

@@ -17,6 +17,7 @@ class EpdFontFamily {
     SUP = 16,           // superscript: glyph scaled 50%, raised ~40% of ascender
     SUB = 32,           // subscript: glyph scaled 50%, lowered ~25% of ascender
   };
+  static constexpr uint8_t TEXT_DECORATION_MASK = static_cast<uint8_t>(UNDERLINE | STRIKETHROUGH);
 
   explicit EpdFontFamily(const EpdFont* regular, const EpdFont* bold = nullptr, const EpdFont* italic = nullptr,
                          const EpdFont* boldItalic = nullptr)
@@ -25,8 +26,13 @@ class EpdFontFamily {
   void getTextDimensions(const char* string, int* w, int* h, Style style = REGULAR) const;
   const EpdFontData* getData(Style style = REGULAR) const;
   const EpdGlyph* getGlyph(uint32_t cp, Style style = REGULAR) const;
+  bool hasGlyph(uint32_t cp, Style style = REGULAR) const;
   int8_t getKerning(uint32_t leftCp, uint32_t rightCp, Style style = REGULAR) const;
+  uint32_t getLigature(uint32_t leftCp, uint32_t rightCp, Style style = REGULAR) const;
   uint32_t applyLigatures(uint32_t cp, const char*& text, Style style = REGULAR) const;
+  static constexpr bool hasTextDecoration(const Style style) {
+    return (static_cast<uint8_t>(style) & TEXT_DECORATION_MASK) != 0;
+  }
 
  private:
   const EpdFont* regular;

lib/EpdFont/FontDecompressor.cpp

@@ -33,12 +33,24 @@ void FontDecompressor::freePageBuffer() {
 }
 
 void FontDecompressor::freeHotGroup() {
-  hotGroup.clear();
-  hotGroup.shrink_to_fit();
+  free(hotGroup);
+  hotGroup = nullptr;
+  hotGroupCapacity = 0;
   hotGroupFont = nullptr;
   hotGroupIndex = UINT16_MAX;
-  hotGlyphBuf.clear();
-  hotGlyphBuf.shrink_to_fit();
+  free(hotGlyphBuf);
+  hotGlyphBuf = nullptr;
+  hotGlyphBufCapacity = 0;
+}
+
+bool FontDecompressor::ensureCapacity(uint8_t*& buf, uint32_t& capacity, uint32_t needed) {
+  if (capacity >= needed) return true;
+  // Grow-only, free-then-malloc: every caller fully rewrites the buffer after a grow, so the
+  // old contents are dead -- freeing first gives the allocator its best shot on a tight heap.
+  free(buf);
+  buf = static_cast<uint8_t*>(malloc(needed));  // owned by FontDecompressor, freed in freeHotGroup()
+  capacity = buf ? needed : 0;
+  return buf != nullptr;
 }
 
 uint16_t FontDecompressor::getGroupIndex(const EpdFontData* fontData, uint32_t glyphIndex) {
@@ -170,24 +182,20 @@ const uint8_t* FontDecompressor::getBitmap(const EpdFontData* fontData, const Ep
   }
 
   // Check if hot group already has this group decompressed — if not, decompress it
-  if (!(!hotGroup.empty() && hotGroupFont == fontData && hotGroupIndex == groupIndex)) {
+  if (!(hotGroup != nullptr && hotGroupFont == fontData && hotGroupIndex == groupIndex)) {
     stats.cacheMisses++;
     const EpdFontGroup& group = fontData->groups[groupIndex];
 
-    hotGroup.resize(group.uncompressedSize);
-    if (hotGroup.empty()) {
+    // ensureCapacity may free the buffer, so the cached-group identity dies with it either way.
+    hotGroupFont = nullptr;
+    hotGroupIndex = UINT16_MAX;
+    if (!ensureCapacity(hotGroup, hotGroupCapacity, group.uncompressedSize)) {
       LOG_ERR("FDC", "Failed to allocate %u bytes for hot group %u", group.uncompressedSize, groupIndex);
-      hotGroupFont = nullptr;
-      hotGroupIndex = UINT16_MAX;
       stats.getBitmapTimeUs += micros() - tStart;
       return nullptr;
     }
 
-    if (!decompressGroup(fontData, groupIndex, hotGroup.data(), group.uncompressedSize)) {
-      hotGroup.clear();
-      hotGroup.shrink_to_fit();
-      hotGroupFont = nullptr;
-      hotGroupIndex = UINT16_MAX;
+    if (!decompressGroup(fontData, groupIndex, hotGroup, group.uncompressedSize)) {
       stats.getBitmapTimeUs += micros() - tStart;
       return nullptr;
     }
@@ -200,18 +208,16 @@ const uint8_t* FontDecompressor::getBitmap(const EpdFontData* fontData, const Ep
   }
 
   // Compact just the requested glyph from byte-aligned data into scratch buffer
-  if (glyph->dataLength > hotGlyphBuf.size()) {
-    hotGlyphBuf.resize(glyph->dataLength);
-  }
-  if (hotGlyphBuf.empty()) {
+  if (!ensureCapacity(hotGlyphBuf, hotGlyphBufCapacity, glyph->dataLength)) {
+    LOG_ERR("FDC", "Failed to allocate %u bytes for glyph scratch", (unsigned)glyph->dataLength);
     stats.getBitmapTimeUs += micros() - tStart;
     return nullptr;
   }
 
   uint32_t alignedOff = getAlignedOffset(fontData, groupIndex, glyphIndex);
-  compactSingleGlyph(&hotGroup[alignedOff], hotGlyphBuf.data(), glyph->width, glyph->height);
+  compactSingleGlyph(&hotGroup[alignedOff], hotGlyphBuf, glyph->width, glyph->height);
   stats.getBitmapTimeUs += micros() - tStart;
-  return hotGlyphBuf.data();
+  return hotGlyphBuf;
 }
 
 // --- Prewarm: pre-decompress glyph bitmaps for a page of text ---

lib/EpdFont/FontDecompressor.h

@@ -2,8 +2,6 @@
 
 #include <InflateReader.h>
 
-#include <vector>
-
 #include "EpdFontData.h"
 
 class FontDecompressor {
@@ -67,13 +65,22 @@ class FontDecompressor {
 
   // Hot group: last decompressed group (byte-aligned) for non-prewarmed fallback path.
   // Kept in byte-aligned format; individual glyphs are compacted on demand into hotGlyphBuf.
+  // Nothrow high-water malloc buffers, NOT std::vector: getBitmap() runs on the render path,
+  // and under -fno-exceptions a vector resize that hits OOM abort()s the firmware instead of
+  // failing (field crash: hotGroup.resize() -> std::bad_alloc -> abort with ~11 KB free).
+  // ensureCapacity() returns false on OOM so the caller can skip the glyph gracefully.
   const EpdFontData* hotGroupFont = nullptr;
   uint16_t hotGroupIndex = UINT16_MAX;
-  std::vector<uint8_t> hotGroup;
+  uint8_t* hotGroup = nullptr;  // owned; freed in freeHotGroup()/dtor
+  uint32_t hotGroupCapacity = 0;
 
   // Scratch buffer for compacting a single glyph from the hot group.
-  // Valid until the next getBitmap() call.
-  std::vector<uint8_t> hotGlyphBuf;
+  // Valid until the next getBitmap() call. Same ownership/OOM contract as hotGroup.
+  uint8_t* hotGlyphBuf = nullptr;
+  uint32_t hotGlyphBufCapacity = 0;
+
+  // Grow (never shrink) an owned buffer to at least `needed` bytes; false on OOM, buffer freed.
+  static bool ensureCapacity(uint8_t*& buf, uint32_t& capacity, uint32_t needed);
 
   void freePageBuffer();
   void freeHotGroup();

lib/EpdFont/SdCardFont.cpp

@@ -1061,6 +1061,28 @@ void SdCardFont::mergeIntoAdvanceTable(uint8_t styleIdx, const AdvanceEntry* sor
   advanceTableSize_[styleIdx] = k;
 }
 
+bool SdCardFont::hasGlyphMeta(uint8_t styleIdx, uint32_t codepoint) const {
+  styleIdx &= (MAX_STYLES - 1);
+  const PerStyle& s = styles_[styleIdx];
+  if (!loaded_ || !s.present) return false;
+  return findGlobalGlyphIndex(s, codepoint) >= 0;
+}
+
+uint16_t SdCardFont::ensureAdvance(uint8_t styleIdx, uint32_t codepoint) {
+  styleIdx &= (MAX_STYLES - 1);
+  if (!loaded_ || !styles_[styleIdx].present) return 0;
+  const uint16_t cached = getAdvance(codepoint, styleIdx);
+  if (cached != 0) return cached;
+  // 0 is either "not in table" or a genuine zero-width glyph; only pay the
+  // SD read when the resident interval table says the glyph exists.
+  if (findGlobalGlyphIndex(styles_[styleIdx], codepoint) < 0) return 0;
+  uint32_t cp = codepoint;
+  fetchAdvancesForCodepoints(&cp, 1, static_cast<uint8_t>(1u << styleIdx));
+  return getAdvance(codepoint, styleIdx);
+}
+
+uint8_t SdCardFont::styleIdxFromMissCtx(void* ctx) { return static_cast<OverflowContext*>(ctx)->styleIdx; }
+
 bool SdCardFont::hasAdvanceTable() const {
   for (uint8_t i = 0; i < MAX_STYLES; i++) {
     if (advanceTable_[i]) return true;

lib/EpdFont/SdCardFont.h

@@ -55,6 +55,23 @@ class SdCardFont {
   // Returns the 12.4 fixed-point advance, or 0 if not found.
   uint16_t getAdvance(uint32_t codepoint, uint8_t style) const;
 
+  // Layout-side metric access — the per-glyph path CpFontAdapter uses while
+  // the FreeInkBook engine measures a chapter. Neither touches bitmap data:
+  // going through getGlyph() would stream every occurrence's bitmap through
+  // the 8-slot overflow ring (one SD read per character — a crawling build).
+  //
+  // hasGlyphMeta answers existence from the resident interval table (no I/O).
+  bool hasGlyphMeta(uint8_t styleIdx, uint32_t codepoint) const;
+  // ensureAdvance returns the 12.4 fixed-point advanceX, fetching the glyph
+  // METADATA from SD once on a miss and merging it into the persistent
+  // advance table (so each unique codepoint costs one small read per
+  // session). Returns 0 when the style lacks the codepoint.
+  uint16_t ensureAdvance(uint8_t styleIdx, uint32_t codepoint);
+
+  // Recover the style index from an EpdFontData::glyphMissCtx (see
+  // fromMissCtx below for recovering the SdCardFont itself).
+  static uint8_t styleIdxFromMissCtx(void* ctx);
+
   // Returns true if advance table is populated for at least one style.
   bool hasAdvanceTable() const;
 

lib/EpdFont/builtinFonts/all.h

@@ -37,5 +37,3 @@
 #include <builtinFonts/ubuntu_10_regular.h>
 #include <builtinFonts/ubuntu_12_bold.h>
 #include <builtinFonts/ubuntu_12_regular.h>
-#include <builtinFonts/ubuntu_14_bold.h>
-#include <builtinFonts/ubuntu_14_regular.h>

lib/EpdFont/scripts/build-font-ids.sh

@@ -94,13 +94,6 @@ ruby -rdigest -e 'puts [
 ].map{|f| Digest::SHA256.hexdigest(File.read(f)).to_i(16) }.sum % (2 ** 32) - (2 ** 31)'
 ))"
 
-echo "#define UI_14_FONT_ID ($(
-ruby -rdigest -e 'puts [
-  "./ubuntu_14_regular.h",
-  "./ubuntu_14_bold.h",
-].map{|f| Digest::SHA256.hexdigest(File.read(f)).to_i(16) }.sum % (2 ** 32) - (2 ** 31)'
-))"
-
 echo "#define SMALL_FONT_ID ($(
 ruby -rdigest -e 'puts [
   "./notosans_8_regular.h",

lib/EpdFont/scripts/build-sd-fonts.py

@@ -33,6 +33,7 @@ import sys
 import tempfile
 import threading
 import time
+import socket
 import urllib.request
 from concurrent.futures import ProcessPoolExecutor, as_completed
 from pathlib import Path
@@ -49,17 +50,44 @@ INSTANCE_DIR = SCRIPT_DIR / "instanced_fonts"
 DEFAULT_FALLBACK_FONT = EPDFONTS_DIR / "builtinFonts/source/NotoSans/NotoSans-Regular.ttf"
 
 
-def download_font(url: str, dest: Path) -> Path:
-    """Download a font file if not already cached. Returns the local path."""
+_orig_getaddrinfo = socket.getaddrinfo
+
+
+def _ipv4_only_getaddrinfo(*args, **kwargs):
+    """getaddrinfo variant that drops AAAA records (IPv4 only)."""
+    return [ai for ai in _orig_getaddrinfo(*args, **kwargs) if ai[0] == socket.AF_INET]
+
+
+def download_font(url: str, dest: Path, retries: int = 3) -> Path:
+    """Download a font file if not already cached. Returns the local path.
+
+    Some sources (e.g. mirrors.ctan.org) are round-robin redirectors that land
+    on a different mirror each request; a mirror may advertise an IPv6 address a
+    host without an IPv6 route cannot reach ([Errno 101] Network is unreachable).
+    Retry on failure, forcing IPv4 resolution after the first attempt.
+    """
     if dest.exists():
         return dest
     dest.parent.mkdir(parents=True, exist_ok=True)
     print(f"  Downloading {dest.name}...")
-    try:
-        urllib.request.urlretrieve(url, dest)
-    except Exception as e:
-        dest.unlink(missing_ok=True)
-        raise RuntimeError(f"Failed to download {url}: {e}") from e
+    last_err = None
+    for attempt in range(1, retries + 1):
+        force_ipv4 = attempt > 1
+        if force_ipv4:
+            socket.getaddrinfo = _ipv4_only_getaddrinfo
+        try:
+            urllib.request.urlretrieve(url, dest)
+            break
+        except Exception as e:  # noqa: BLE001 - reported via RuntimeError below
+            last_err = e
+            dest.unlink(missing_ok=True)
+            if attempt < retries:
+                print(f"  Attempt {attempt} failed ({e}); retrying (IPv4-only)...")
+        finally:
+            if force_ipv4:
+                socket.getaddrinfo = _orig_getaddrinfo
+    else:
+        raise RuntimeError(f"Failed to download {url}: {last_err}") from last_err
     size_kb = dest.stat().st_size / 1024
     print(f"  Downloaded {dest.name} ({size_kb:.0f} KB)")
     return dest

lib/EpdFont/scripts/convert-builtin-fonts.sh

@@ -28,42 +28,23 @@ for size in ${NOTOSANS_FONT_SIZES[@]}; do
   done
 done
 
-# Small UI chrome (button devices, uiScale 1.0). Rendered 1-bit: crisp at these
-# sizes and half the flash of 2-bit.
 UI_FONT_SIZES=(10 12)
-# Larger UI chrome substituted in on touch/high-density boards via the uiScale
-# remap (see src/main.cpp setupFonts). Rendered 2-bit so it stays smooth when
-# enlarged. Touch boards use uiScale 1.2, so UI_12 -> 14.4 -> 14 is the size the
-# remap actually lands on; add larger sizes here if a board adopts a higher scale.
-UI_FONT_SIZES_LARGE=(14)
 UI_FONT_STYLES=("Regular" "Bold")
 
-# Ubuntu lacks the Latin Extended Additional block (U+1EA0-U+1EF9) used for
-# Vietnamese tone marks. Append a Vietnamese-only Ubuntu cut so those glyphs are
-# filled from it while every glyph Ubuntu already has stays unchanged (fontstack
-# is ordered by descending priority). NotoSansHebrew fills U+05D0-U+05EA so the
-# Hebrew UI translation renders in menus and settings.
-generate_ui_font() {
-  local size="$1" style="$2" extra_flags="$3"
-  local font_name="ubuntu_${size}_$(echo $style | tr '[:upper:]' '[:lower:]')"
-  local font_path="../builtinFonts/source/Ubuntu/Ubuntu-${style}.ttf"
-  local hebrew_path="../builtinFonts/source/NotoSansHebrew/NotoSansHebrew-${style}.ttf"
-  local viet_path="../builtinFonts/source/Ubuntu/Ubuntu-Vietnamese-${style}.ttf"
-  local output_path="../builtinFonts/${font_name}.h"
-  python fontconvert.py $font_name $size $font_path $hebrew_path $viet_path \
-    --additional-intervals 0x05D0,0x05EA $extra_flags > $output_path
-  echo "Generated $output_path"
-}
-
 for size in ${UI_FONT_SIZES[@]}; do
   for style in ${UI_FONT_STYLES[@]}; do
-    generate_ui_font $size $style ""
-  done
-done
-
-for size in ${UI_FONT_SIZES_LARGE[@]}; do
-  for style in ${UI_FONT_STYLES[@]}; do
-    generate_ui_font $size $style "--2bit --compress"
+    font_name="ubuntu_${size}_$(echo $style | tr '[:upper:]' '[:lower:]')"
+    font_path="../builtinFonts/source/Ubuntu/Ubuntu-${style}.ttf"
+    hebrew_path="../builtinFonts/source/NotoSansHebrew/NotoSansHebrew-${style}.ttf"
+    # Ubuntu lacks the Latin Extended Additional block (U+1EA0-U+1EF9) used for
+    # Vietnamese tone marks. Append a Vietnamese-only Ubuntu cut so those glyphs
+    # are filled from it while every glyph Ubuntu already has stays unchanged
+    # (fontstack is ordered by descending priority).
+    viet_path="../builtinFonts/source/Ubuntu/Ubuntu-Vietnamese-${style}.ttf"
+    output_path="../builtinFonts/${font_name}.h"
+    python fontconvert.py $font_name $size $font_path $hebrew_path $viet_path \
+      --additional-intervals 0x05D0,0x05EA > $output_path
+    echo "Generated $output_path"
   done
 done
 

lib/EpdFont/scripts/sd-fonts.yaml

@@ -132,7 +132,16 @@ families:
       bold:       {url: "https://raw.githubusercontent.com/impallari/Libre-Baskerville/master/fonts/ttf/LibreBaskerville-Bold.ttf"}
       italic:     {url: "https://raw.githubusercontent.com/impallari/Libre-Baskerville/master/fonts/ttf/LibreBaskerville-Italic.ttf"}
       bolditalic: {url: "https://raw.githubusercontent.com/impallari/Libre-Baskerville/master/fonts/ttf/LibreBaskerville-BoldItalic.ttf"}
-    
+
+  - name: Vollkorn
+    description: "A serif for bread and butter use by Friedrich Althausen (Latin, Greek, Cyrillic)"
+    intervals: latin-ext,greek,cyrillic
+    sizes: [12, 14, 16, 18]
+    styles:
+      regular:    {url: "https://raw.githubusercontent.com/google/fonts/main/ofl/vollkorn/Vollkorn%5Bwght%5D.ttf", variable: {wght: 400}}
+      bold:       {url: "https://raw.githubusercontent.com/google/fonts/main/ofl/vollkorn/Vollkorn%5Bwght%5D.ttf", variable: {wght: 700}}
+      italic:     {url: "https://raw.githubusercontent.com/google/fonts/main/ofl/vollkorn/Vollkorn-Italic%5Bwght%5D.ttf", variable: {wght: 400}}
+      bolditalic: {url: "https://raw.githubusercontent.com/google/fonts/main/ofl/vollkorn/Vollkorn-Italic%5Bwght%5D.ttf", variable: {wght: 700}}
 
   # ── Sans-serif ─────────────────────────────────────────────────────────