CrossVi

Open-source e-reader firmware for Xteink X3 and X4.
Based on CrossPoint and designed for a focused, button-driven reading experience.

CrossVi extends CrossPoint Reader with a faster library, detailed reading statistics and achievements, flexible sleep screens, user-made vocabulary sets, and additional safeguards for data stored on the SD card.

Warning

CrossVi has not yet been validated on every newer X3/X4 hardware revision. Read Hardware compatibility before flashing.

Download v1.1.3 · Installation · User Guide · CrossVi Tools · Report a Bug · Contributing

Highlights

• Reading: EPUB, TXT, Markdown, XTC, XTCH, and BMP.
• Library: Four Home layouts, list and cover views, search, sorting, paging, pinning, responsive incremental loading, EPUB image optimization, and reusable cover caches.
• Reader tools: Bookmarks, highlights, dictionary lookup, in-book search, clipping export, screenshots, finished-book details, reading achievements, and device, book, and calendar statistics.
• Customization: Built-in Noto Serif and downloadable fonts up to 28 pt, per-book typography, margins, spacing, orientation, image handling, and reader dark mode.
• Sleep screens: Default, cover, reading-statistics, and custom BMP/PNG modes; custom images support transparency and keep independent size and position settings.
• Learning and migration: Vocabulary quizzes using the built-in 3,000-word English-Vietnamese set or a user-made spreadsheet set, plus one-time reading-statistics import from CPR-vCodex.
• Connectivity and tools: Wi-Fi file transfer, OPDS, Calibre/WebDAV, KOReader Sync, OTA, Nearby Sync, and browser tools for sleep images, vocabulary sets, and firmware installation.
• Device and reliability: Configurable buttons, sleep screens, Quick Resume, clock, automatic and tilt page turns, plus transactional storage for important data.

Installation

Download firmware.bin from the latest CrossVi release.

For an existing CrossVi installation with a compatible OTA layout, open CrossVi Tools in Chrome or Edge on a desktop computer, choose Install firmware, and select the downloaded file. The installer writes the inactive application slot and keeps books and settings.

CrossVi Tools is not an unlocker or a first-install tool. For a first installation on a known-compatible, recoverable device, select Custom .bin in the CrossPoint web flasher. Back up the SD card before either installation method.

Hardware compatibility

CrossVi targets the Xteink X3 and X4, but production revisions may use different display or power hardware.

• New X3 units: If you have just received the device and have never flashed custom firmware, stay on stock firmware for now. New production runs may use the UC8279 display controller. CrossVi can detect it, but support still needs validation on the new hardware. See the upstream controller work.
• New X4 units: Some revisions require a battery-latch fix to remain powered without USB. CrossVi 1.1.3 includes that behavior, but it has not yet been validated on a new-revision X4.

Keep the SD card backed up and flash only a recoverable device.

Build from source

Requirements: pioarduino, Python 3.8+, Git, and the repository submodules.

git clone --recursive https://github.com/tvhdc/crossvi.git
cd crossvi
pio run -e default

The firmware is written to .pio/build/default/firmware.bin.

The desktop simulator can check build, boot, UI, and basic application flows:

python3 scripts/run_simulator.py x3
python3 scripts/run_simulator.py x4

Hardware-dependent behaviour such as e-paper refresh, ghosting, SD timing, power use, buttons, and sleep/wake must be tested on a physical device.

Documentation

• User Guide
• CrossVi Tools (source)
• Contributing
• Supported file formats
• Wi-Fi file transfer
• Troubleshooting

Development transparency

CrossVi is developed with AI assistance. AI tools help with code exploration, drafting changes, and reviewing tests. The maintainer makes the design decisions, reviews and validates every release, and remains responsible for the firmware.

Support

If CrossVi is useful to you, you can support its development on Ko-fi.

Credits

CrossVi is a fork of CrossPoint Reader, which remains its technical foundation. It also adapts selected ideas from CrossInk, CPR-vCodex, and other community contributions where they fit the X3/X4 hardware.

CrossVi is licensed under the MIT License, preserves upstream attribution, and is not affiliated with Xteink.