fix: update README.md to reflect the current state of crosspoint (#1812)

## Summary

As noted in
[#1680](https://github.com/crosspoint-reader/crosspoint-reader/discussions/1680#discussioncomment-16661106),
the README hasn't been updated in a while and has fallen behind the
actual firmware. This PR brings it up to date.

Beyond the feature list, I added a section acknowledging community forks
worth knowing about. I also took some deliberate editorial choices
around how CrossPoint is framed — I think it has the potential to be
more than just "an alternative Xteink firmware", and the wording
reflects that.

A note on process: I wrote the bulk of the text myself, but used AI
tools to scan the codebase and catch features I might have missed, and
to clean up my English (I'm fluent but not a native speaker). If any
line reads as unnatural or AI-sounding, please flag it — I'd rather fix
it than leave it.

---

One thing outside the scope of this PR: I think the cover photo could
use a refresh, ideally replaced with a small gallery showing different
CrossPoint screens. If you have a professional camera and an Xteink
device and want to help with that, let me know.

---------

Co-authored-by: Zach Nelson <zach@zdnelson.com>
This commit is contained in:
Uri Tauber
2026-05-15 15:38:22 -05:00
committed by GitHub
co-authored by Zach Nelson
parent 43b20bd8be
commit 0fbe6ff469
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@@ -1,53 +1,54 @@
# CrossPoint Reader
Firmware for **Xteink** e-paper display readers (X3 and X4) (unaffiliated with Xteink).
Built using **PlatformIO** and targeting the **ESP32-C3** microcontroller.
CrossPoint is open-source e-reader firmware - community-built, fully hackable, free forever. It's maintained by a growing community of developers and readers who believe your device should do what you want - not what a manufacturer decided for you.
CrossPoint Reader is a purpose-built firmware designed to be a drop-in, fully open-source replacement for the official
Xteink firmware. It aims to match or improve upon the standard EPUB reading experience.
**Now running on:** ESP32C3-based Xteink [X4](https://www.xteink.com/products/xteink-x4) and [X3](https://www.xteink.com/products/xteink-x3).
![](./docs/images/cover.jpg)
![CrossPoint Reader running on Xteink device](./docs/images/cover.jpg)
## Motivation
## What can CrossPoint do?
E-paper devices are fantastic for reading, but most commercially available readers are closed systems with limited
customisation. **Xteink** devices (such as the X3 and X4) are affordable e-paper readers, however the official firmware remains closed.
CrossPoint exists partly as a fun side-project and partly to open up the ecosystem and truly unlock the device's
potential.
- **Reader engine**: EPUB 2/3 rendering with embedded-style option, image handling, hyphenation, kerning, chapter navigation, footnotes, go-to-percent, auto page turn, orientation control, focus reading, KOReader progress sync and more.
CrossPoint Reader aims to:
* Provide a **fully open-source alternative** to the official firmware.
* Offer a **document reader** capable of handling EPUB content on constrained hardware.
* Support **customisable font, layout, and display** options.
* Run purely on **Xteink hardware**.
- **Various formats**: native handling for `.epub`, `.xtc/.xtch`, `.txt`, and `.bmp`.
This project is **not affiliated with Xteink**; it's built as a community project.
- **Screenshots.**
## Features & Usage
- **Custom fonts**: install your favorite fonts on the SD card.
- [x] EPUB parsing and rendering (EPUB 2 and EPUB 3)
- [x] Image support within EPUB
- [x] Saved reading position
- [x] File explorer with file picker
- [x] Basic EPUB picker from root directory
- [x] Support nested folders
- [ ] EPUB picker with cover art
- [x] Custom sleep screen
- [x] Cover sleep screen
- [x] Wifi book upload
- [x] Wifi OTA updates
- [x] KOReader Sync integration for cross-device reading progress
- [x] Configurable font, layout, and display options
- [ ] User provided fonts
- [ ] Full UTF support
- [x] Screen rotation
- **Tilt page turn (X3 only)**.
Multi-language support: Read EPUBs in various languages, including English, Spanish, French, German, Italian, Portuguese, Russian, Ukrainian, Polish, Swedish, Norwegian, [and more](./USER_GUIDE.md#supported-languages).
- **Library workflow**: folder browser, hidden-file toggle, long-press delete, recent books, SD-cache management.
See [the user guide](./USER_GUIDE.md) for instructions on operating CrossPoint, including the
[KOReader Sync quick setup](./USER_GUIDE.md#367-koreader-sync-quick-setup).
- **Wireless workflows**:
- File transfer web UI
- EPUB Optimizer
- Web settings UI/API (edit many device settings from browser)
- WebSocket fast uploads
- WebDAV handler
- AP mode (hotspot) and STA mode (join existing WiFi), both with QR helpers
- Calibre wireless connect flow
- OPDS browser with saved servers (up to 8), search, pagination, and direct download
- OTA update checks and installs from GitHub releases
For more details about the scope of the project, see the [SCOPE.md](SCOPE.md) document.
- **Customization**: multiple themes (Classic, Lyra, Lyra Extended, RoundedRaff), sleep screen modes, front/side button remapping, status bar controls, power-button behavior, refresh cadence, and more.
- **Localization**: 22 UI languages and counting.
### Coming soon:
- RTL support — Arabic, Hebrew, and Farsi.
- Bookmarks.
- Dictionary lookup — inline word lookup without leaving the reader.
- More themes.
- Much more! stay tuned.
---
## USB-locked devices (Xteink Unlocker)
@@ -57,90 +58,112 @@ https://crosspointreader.com/#unlock-tool before you can flash CrossPoint.
**You do not need this tool if you bought your device directly from xteink.com.** Those units are not locked.
**Not sure if your device is locked?** Power it on, connect the USB-C cable, and try flashing via the web flasher first
(see [Installing](#installing) below). If the browser's serial device picker does not show your device, try a different
**Not sure if your device is locked?** Power it on, connect the USB-C cable, and try flashing via the web flasher first (see
[Install firmware](#install-firmware) below). If the browser's serial device picker does not show your device, try a different
USB port or browser before assuming the device is locked. Only reach for the unlocker if the device still doesn't appear.
> ### ⚠️ WARNING: READ THIS BEFORE USING THE UNLOCKER ⚠️
>
>
> **The only officially supported firmwares in the unlock tool are CrossPoint and CrossInk.**
>
>
> 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.**
## Installing
## Install firmware
### Web (latest firmware)
### Web installer (recommended)
1. Connect your Xteink device to your computer via USB-C and wake/unlock the device
2. Go to https://xteink.dve.al/ and click "Flash CrossPoint firmware"
1. Connect your device to your computer via USB-C and wake/unlock the device
2. Go to https://crosspointreader.com/#flash-tools, select device (X3 or X4), and choose an official CrossPoint release.
To revert back to the official firmware, you can flash the latest official firmware from https://xteink.dve.al/, or swap
back to the other partition using the "Swap boot partition" button here https://xteink.dve.al/debug.
### Web installer (specific version)
### Web (specific firmware version)
1. Connect your device to your computer via USB-C and wake/unlock the device
2. Download a `firmware.bin` from [Releases](https://github.com/crosspoint-reader/crosspoint-reader/releases), local build, or continuous integration artifact.
3. Go to https://crosspointreader.com/#flash-tools, select device (X3 or X4), click "Custom .bin" and upload a `firmware.bin`.
1. Connect your Xteink device to your computer via USB-C
2. Download the `firmware.bin` file from the release of your choice via the [releases page](https://github.com/crosspoint-reader/crosspoint-reader/releases)
3. Go to https://xteink.dve.al/ and flash the firmware file using the "OTA fast flash controls" section
### Revert to Official Firmware
To revert back to the official firmware, you can flash the latest official firmware from https://xteink.dve.al/, or swap
back to the other partition using the "Swap boot partition" button here https://xteink.dve.al/debug.
To revert to the official firmware, you can also flash the latest official firmware using https://crosspointreader.com/#flash-tools.
### Command line (specific firmware version)
### Command line
1. Install [`esptool`](https://github.com/espressif/esptool):
1. Install [`esptool`](https://github.com/espressif/esptool) :
```bash
pip install esptool
```
2. Download the `firmware.bin` file from the release of your choice via the [releases page](https://github.com/crosspoint-reader/crosspoint-reader/releases)
3. Connect your Xteink device to your computer via USB-C.
4. Note the device location. On Linux, run `dmesg` after connecting. On MacOS, run :
2. Download `firmware.bin` from the [releases page](https://github.com/crosspoint-reader/crosspoint-reader/releases).
3. Connect your device via USB-C.
4. Find the device port. On Linux, run `dmesg` after connecting. On macOS:
```bash
log stream --predicate 'subsystem == "com.apple.iokit"' --info
```
5. Flash the firmware :
5. Flash:
```bash
esptool.py --chip esp32c3 --port /dev/ttyACM0 --baud 921600 write_flash 0x10000 /path/to/firmware.bin
```
Change `/dev/ttyACM0` to the device for your system.
Adjust `/dev/ttyACM0` to match your system.
### Manual
See [Development](#development) below.
See [Development quick start](#development-quick-start) below.
## Development
---
## Documentation
- [User Guide](./USER_GUIDE.md)
- [Web server usage](./docs/webserver.md)
- [Web server endpoints](./docs/webserver-endpoints.md)
- [Project scope](./SCOPE.md)
- [Contributing docs](./docs/contributing/README.md)
---
## Development quick start
### Prerequisites
* **PlatformIO Core** (`pio`) or **VS Code + PlatformIO IDE**
* Python 3.8+
* USB-C cable for flashing the ESP32-C3
* Xteink device (X3 or X4)
- [pioarduino](https://github.com/pioarduino/pioarduino) or VS Code + pioarduino plugin
- Python 3.8+
- `clang-format` 21
- USB-C cable supporting data transfer
### Checking out the code
### Setup
CrossPoint uses PlatformIO for building and flashing the firmware. To get started, clone the repository:
```
```bash
git clone --recursive https://github.com/crosspoint-reader/crosspoint-reader
cd crosspoint-reader
# Or, if you've already cloned without --recursive:
# if cloned without --recursive:
git submodule update --init --recursive
```
### Flashing your device
### Build / flash / monitor
Connect your Xteink device to your computer via USB-C and run the following command.
```sh
```bash
pio run --target upload
```
### Contributor pre-PR checks
```bash
./bin/clang-format-fix
pio check -e default
pio run -e default
```
### Debugging
After flashing the new features, its recommended to capture detailed logs from the serial port.
@@ -150,7 +173,9 @@ First, make sure all required Python packages are installed:
```python
python3 -m pip install pyserial colorama matplotlib
```
after that run the script:
After that run the script:
```sh
# For Linux
# This was tested on Debian and should work on most Linux systems.
@@ -159,63 +184,72 @@ python3 scripts/debugging_monitor.py
# For macOS
python3 scripts/debugging_monitor.py /dev/cu.usbmodem2101
```
Minor adjustments may be required for Windows.
---
## Internals
CrossPoint Reader is pretty aggressive about caching data down to the SD card to minimise RAM usage. The ESP32-C3 only
has ~380KB of usable RAM, so we have to be careful. A lot of the decisions made in the design of the firmware were based
on this constraint.
CrossPoint Reader is pretty aggressive about caching data down to the SD card to minimise RAM usage. The ESP32-C3 only has ~380KB of usable RAM, so we have to be careful. A lot of the decisions made in the design of the firmware were based on this constraint.
### Data caching
The first time chapters of a book are loaded, they are cached to the SD card. Subsequent loads are served from the
cache. This cache directory exists at `.crosspoint` on the SD card. The structure is as follows:
```
```text
.crosspoint/
├── epub_12471232/ # Each EPUB is cached to a subdirectory named `epub_<hash>`
│ ├── progress.bin # Stores reading progress (chapter, page, etc.)
│ ├── cover.bmp # Book cover image (once generated)
│ ├── book.bin # Book metadata (title, author, spine, table of contents, etc.)
│ └── sections/ # All chapter data is stored in the sections subdirectory
│ ├── 0.bin # Chapter data (screen count, all text layout info, etc.)
│ ├── 1.bin # files are named by their index in the spine
├── epub_<hash>/ # one directory per book, named by content hash
│ ├── progress.bin # reading position (chapter, page, etc.)
│ ├── cover.bmp # generated cover image
│ ├── book.bin # metadata: title, author, spine, TOC
│ └── sections/ # per-chapter layout cache
│ ├── 0.bin
│ ├── 1.bin
│ └── ...
└── epub_189013891/
```
Deleting the `.crosspoint` directory will clear the entire cache.
Due the way it's currently implemented, the cache is not automatically cleared when a book is deleted and moving a book
file will use a new cache directory, resetting the reading progress.
Removing `/.crosspoint` clears all cached metadata and forces a full regeneration on next open. Note: the cache isn't cleared automatically when you delete a book, and moving a file to a new path resets its reading progress.
For more details on the internal file structures, see the [file formats document](./docs/file-formats.md).
---
## Contributing
Contributions are very welcome!
Contributions are welcome. If you're new to the codebase, start with the [contributing docs](./docs/contributing/README.md). For things to work on, check the [ideas discussion board](https://github.com/crosspoint-reader/crosspoint-reader/discussions/categories/ideas) — leave a comment before starting so we don't duplicate effort.
If you are new to the codebase, start with the [contributing docs](./docs/contributing/README.md).
If you're looking for a way to help out, take a look at the [ideas discussion board](https://github.com/crosspoint-reader/crosspoint-reader/discussions/categories/ideas).
If there's something there you'd like to work on, leave a comment so that we can avoid duplicated effort.
Everyone here is a volunteer, so please be respectful and patient. For more details on our governance and community
principles, please see [GOVERNANCE.md](GOVERNANCE.md).
### To submit a contribution:
1. Fork the repo
2. Create a branch (`feature/dithering-improvement`)
3. Make changes
4. Submit a PR
Everyone here is a volunteer, so please be respectful and patient. For governance and community expectations, see [GOVERNANCE.md](./GOVERNANCE.md).
---
CrossPoint Reader is **not affiliated with Xteink or any manufacturer of the hardware**.
## Community forks
Huge shoutout to [**diy-esp32-epub-reader** by atomic14](https://github.com/atomic14/diy-esp32-epub-reader), which was a project I took a lot of inspiration from as I
was making CrossPoint.
One of the best things about open source is that anyone can take the code in a different direction. If you need something outside CrossPoint's [scope](./SCOPE.md), check out the community forks:
- [CrossInk](https://github.com/uxjulia/CrossInk) — Typography and reading tracking: Bionic Reading (bolds word stems to create fixation points), guide dots between words, improved paragraph indents, and replaces the default fonts with ChareInk/Lexend/Bitter.
- [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.
- [crosspoint-reader (jpirnay)](https://github.com/jpirnay/crosspoint-reader) — Faster integration of functionality. Tracks upstream PRs and integrates the good ones ahead of the official merge.
- [crosspoint-reader-cjk](https://github.com/aBER0724/crosspoint-reader-cjk) — Purpose-built for Chinese, Japanese, and Korean reading.
- [inx](https://github.com/obijuankenobiii/inx) — Completely reimagines the user interface with tabbed navigation.
- ~~[PlusPoint](https://github.com/ngxson/pluspoint-reader) — custom JS apps support.~~ (Unmaintained)
- [crosspoint-reader-papers3](https://github.com/juicecultus/crosspoint-reader-papers3) — Crosspoint port for M5Stack Paper S3.
**Note:** Many of these features will make their way into CrossPoint over time. We maintain a slower pace to ensure rock-solid stability and squash bugs before they reach your device.
Want to build your own device? Be sure to check out the [de-link](https://github.com/iandchasse/de-link) project.
---
CrossPoint Reader is **not affiliated with Xteink or any device manufacturer**.
Huge shoutout to [diy-esp32-epub-reader](https://github.com/atomic14/diy-esp32-epub-reader), which inspired this project.