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All firmware

Reader fork

SUMI

v0.6.3 · X4 (X3 partial)

Offline apps, dictionary & Lua plugins

X3 ~ X4 ✓ Risk: Medium

Best for: Tinkerers who want a do-it-all offline device — and the most genuine “plugin” story in the scene.

GitHub repo Flasher / tool

What it adds

  • A sandboxed Lua plugin system — drop .lua files into /custom/ on the SD card and they become launchable apps. The only genuine on-device scriptable plugins in the scene.
  • ~20 built-in apps: chess, sudoku, notes, even a Game Boy emulator (“SumiBoy”).
  • A StarDict dictionary with fuzzy matching for offline word lookup; reading stats and achievements.
  • Offline-first by design — no WiFi at all. Built on Papyrix + CrossPoint; full on X4, partial on X3 (B&W reading works, grayscale still uses the X4 path).
SUMI firmware running on the Xteink
SUMI’s home screen — the signature sumi-e ink-art border, with Files and Menu controls.

How to install

via web flasher
  1. 1

    Connect an unlocked X3/X4 by USB-C in Chrome or Edge and wake it.

  2. 2

    Open sumi.page/flasher and pick your model.

  3. 3

    Flash, then reboot (Reset, hold Power 3–5s). Books and dictionaries go on the SD card.

Locked devices & SUMI

Unlocked X4 (X3 partial). Flash over USB-C at sumi.page/flasher — SUMI ships no Unlocker or SD-update path, so it isn’t for locked units.

Not sure if your unit is locked? Read the locked-device safety brief, or the full locked vs unlocked buying guide.

How to go back

  1. 1Re-flash stock — the same web flasher offers official Xteink firmware.
  2. 2Restore a backup — “Write full flash from file” if you saved one first.
  3. 3Swap boot partition — a quick rollback at xteink.dve.al/debug.

On a locked unit you lose the USB safety net — that’s why locked devices stick to CrossPoint/CrossInk.

Heads-up: Offline by design — no WiFi transfer, so load books via SD card or the flasher’s file tools. X3 support is partial (grayscale artifacts). A younger project than CrossPoint, but actively maintained.

New to flashing? The mechanics are the same across forks. See the five flashing methods on the directory, or the step-by-step flash CrossPoint without panicking guide.

Other firmware

Full directory →

CrossPoint Reader

The main community firmware

The default — best all-round reader

Full guide

CrossInk

Typography + reading stats fork

Reading stats, Bionic Reading, glyph fixes

Full guide

Papyrix

More formats, one binary for both devices

FB2 / Markdown / HTML, multi-script

Full guide

CrossPet

Gamified reading + Vietnamese

Vietnamese UI + gamified virtual pet & games

Full guide

Microreader

Deliberately minimal, EPUB-only

Minimal, distraction-free EPUB-only

Full guide

AvesO3

For AO3 fanfiction readers

AO3 fanfiction workflow

Full guide

SUMI details verified June 24, 2026 against its GitHub repo, README and releases. PocketInk is independent and not affiliated with Xteink. Firmware names and versions change quickly — check the repo for the latest.