Open-source Β· ESP32-C3 Β· Xteink X4

Your pocket e-reader β€”
with a virtual chicken.

✨ Custom firmware for the Xteink X4 e-reader β€” built on CrossPoint Reader

Open-source firmware for the Xteink X4 β€” a $69 pocket e-reader with physical buttons, SD card, and weeks of battery. CrossPet adds Vietnamese UI, a virtual chicken pet, mini games, reading stats, weather & lunar calendar.

4.3" E-Ink  Β·  Physical buttons  Β·  SD Card  Β·  WiFi + BLE  Β·  Weeks of battery  Β·  100g pocket-sized

Your chicken grows with every page

The more you read, the more your chicken evolves. From a tiny egg to a proud rooster with a book.

Egg
0 pages
Chick
100 pages
Hen
500 pages
Rooster
2000 pages

Track reading stats, earn streaks, and watch your pixel chicken come to life.

Built for readers, by readers

CrossPet fits into your reading life β€” however you read.

The Commuter

Sunlight-readable e-ink display. Weeks of battery life. Resume exactly where you left off β€” even across multiple devices.

The Bookworm

Anti-aliased text with 3 font families including OpenDyslexic. Adjustable spacing, margins, and 4 font sizes. Your eyes will thank you.

The Tinkerer

Fully open-source firmware. WiFi book upload, OTA updates. Hack it, mod it, make it yours.

The Minimalist

No ads. No tracking. No cloud dependency. Physical buttons. One purpose: focused reading.

What makes CrossPet special

Everything you need for great reading β€” plus the things that make it uniquely CrossPet.

Core Reading

  • EPUB 2 & 3 with image support
  • Anti-aliased grayscale text rendering
  • 3 font families Γ— 4 sizes Γ— 4 styles
  • Multi-language hyphenation engine
  • KOReader Sync β€” cross-device progress
  • WiFi book upload + Calibre + OPDS browser
  • 4 screen orientations (Portrait, Landscape CW/CCW, Inverted)
  • Fully remappable physical buttons
  • Custom sleep screens (cover art, custom images)
  • SD-first aggressive layout caching

CrossPet Exclusives

  • Virtual Chicken β€” pixel companion that grows with your reading
  • Reading Stats β€” daily time, streaks & session tracking
  • Stats sleep screen dashboard
  • Weather Widget β€” Open-Meteo API, shown in header & clock
  • Clock + Lunar Calendar with month navigation
  • Daily Literary Quotes on clock sleep screen
  • BLE Remote & Presenter β€” keyboard & slide control
  • Mini Games β€” Chess, Caro, Sudoku, Minesweeper, 2048
  • Pomodoro Timer
  • Vietnamese fonts β€” full diacritics, anti-aliased on e-ink
  • Full Vietnamese UI β€” menus, settings, all screens

Vietnamese fonts that actually work on e-ink

CrossPet includes 3 font families (Bookerly, Noto Sans, Bokerlam) with full Vietnamese diacritics support β€” Δƒ, Γ’, Δ‘, Γͺ, Γ΄, Ζ‘, Ζ° and all tone marks render perfectly with anti-aliased grayscale on the 800Γ—480 e-ink display. Bokerlam is a handcrafted Vietnamese font optimized for readability. No more broken characters or missing glyphs.

See it in action

Real CrossPet firmware running on a real Xteink X4 β€” Vietnamese UI, virtual chicken, reading progress, all on e-ink.

CrossPet Reader homescreen on Xteink X4 showing Vietnamese UI, book covers, reading progress, and virtual chicken menu

Home screen: weather, book cover, reading progress, virtual chicken β€” all in Vietnamese.

Take a break β€” play a game

Five pixel-perfect mini games built right into the firmware. No install, no internet, just fun.

Chess

Classic chess with AI opponent. Multiple difficulty levels.

Caro (Gomoku)

Five-in-a-row on e-ink. Crisp and satisfying.

Sudoku

Logic puzzles in 4 difficulty tiers. Auto-save progress.

Minesweeper

The classic. Pixel-perfect on the 800x480 display.

2048

Slide and merge tiles. One more game before bed...

More than just a reader

Useful tools built right into the firmware β€” no apps, no internet required.

Clock & Lunar Calendar

Monthly calendar with lunar date integration. Navigate months with Left/Right buttons. Vietnamese lunar calendar shows "Γ‚m lα»‹ch" range in header. Perfect for tracking traditional holidays.

Weather Widget

Current weather from Open-Meteo API β€” free, no API key needed. Shows temperature in header bar, clock sleep screen, and dedicated weather app. Auto-syncs when WiFi connects.

Daily Literary Quotes

28 rotating literary quotes displayed on the clock sleep screen. A new quote every day to inspire your reading journey.

Pomodoro Timer

Built-in focus timer for productive reading sessions. Set work/break intervals and stay on track β€” right on your e-reader.

Your e-reader is also a wireless presenter

Connect to your laptop via BLE and control presentations with physical buttons β€” next slide, previous slide, from across the room. No dongle, no app. Just pair and present.

BLE 5.0 HID Keyboard Page Remote No Dongle

Official vs CrossPoint vs CrossPet

Feature Official CrossPoint CrossPet
Open sourceβœ—βœ“βœ“
Anti-aliased text renderingβœ—βœ“βœ“
Custom font familiesβœ—βœ“ (3 families)βœ“ (3 families + Bokerlam)
KOReader Syncβœ—βœ“βœ“
Calibre integrationβœ—βœ“βœ“
OPDS browserβœ—βœ“βœ“
WiFi book uploadβœ“βœ“βœ“
OTA firmware updatesβœ“βœ“βœ“
Remappable buttonsβœ—βœ“βœ“
Vietnamese UIβœ—βœ—βœ“
Virtual Chicken companionβœ—βœ—βœ“
Reading stats & streaksβœ—βœ—βœ“
Weather widgetβœ—βœ—βœ“
Clock + Lunar calendarβœ—βœ—βœ“
Pomodoro timerβœ—βœ—βœ“
Literary quotes on sleep screenβœ—βœ—βœ“
Mini gamesβœ—βœ—βœ“
BLE remote / presenterβœ—βœ—βœ“

Xteink X4 β€” honest comparison

Not the best screen. Not the most features. But the only one you can hack, pocket, and make truly yours.

Spec Xteink X4 + CrossPet Kindle Paperwhite Boox Page Smartphone
Price $69 ~$150 ~$250 $200–1200
Screen 4.3" E-Ink 800Γ—480 β€” small but sharp enough 6.8" E-Ink 1236Γ—1648 β€” bigger, sharper 7" E-Ink 1264Γ—1680 β€” best resolution 6"+ LCD/OLED β€” high brightness, more eye strain
Battery Weeks (no backlight, ultra-low power) Weeks Days–Week (Android drains faster) Hours
Backlight None β€” can't read in the dark Warm light, adjustable Warm + cold light Full brightness
Touchscreen None β€” buttons only βœ“ βœ“ βœ“
Weight ~100g 205g 195g 150–230g
Open-source firmware CrossPet β€” fully open source, fully customizable Locked down, Amazon controls Android, partially open Locked ecosystem
Sideload books SD card + WiFi upload Send-to-Kindle, limited formats Full Android, any app Yes
Ads None, ever Yes (pay extra to remove) None Common in free apps
Storage SD card β€” swap anytime, unlimited 8–32GB fixed, no expansion 64GB fixed 64–512GB
Personality Virtual chicken, games, lunar calendar, weather Standard UI, limited customization Android apps, but generic Many apps, but easy to get distracted
Pocket-sized Fits in any pocket Too large for pockets Too large for pockets Varies

No backlight, no touchscreen, small screen β€” but at $69, you get an open-source e-ink reader that fits in your pocket, runs for weeks, and has a virtual chicken. Trade-offs worth making.