Open-source ESP32-C3 firmware replacing closed Xteink X4 official firmware, with EPUB 2/3 rendering, KOReader Sync, WiFi OTA, and PlatformIO build toolchain.
Key Takeaways
Targets ESP32-C3 with ~380KB usable RAM; aggressive SD card caching offloads chapter layout data to stay within memory limits.
Features EPUB 2/3 parsing, cover art, nested folders, WiFi book upload, KOReader Sync for cross-device progress, and custom fonts with full UTF support.
Flash via browser at xteink.dve.al or esptool.py; dual-partition setup allows one-click revert to official firmware.
Cache stored in .crosspoint/epub_<hash>/ on SD; deleting a book does not auto-clear its cache, and moving a file resets reading progress.
Built with PlatformIO targeting ESP32-C3; credits atomic14’s diy-esp32-epub-reader as a primary inspiration.
Hacker News Comment Review
Commenters flagged that Xteink has begun blocking firmware changes on some units, seen as contrary to the openness that made the device appealing to its buyer base.
The block is reportedly already bypassed; a Reddit thread is circulating with details, but the situation signals a potential cat-and-mouse dynamic going forward.
Notable Comments
@jauntywundrkind: bypass already exists per Reddit, but notes Xteink’s move is “entirely out of step” with what makes these devices popular.
