XTEINK firmware FAQ

Custom firmware replaces the stock XTEINK software with a community-built reader OS. The main one, CrossPoint, is open-source (MIT, written in C, ~5.4k GitHub stars) and adds real EPUB 2/3 rendering, hyphenation, bookmarks, custom SD-card fonts, Wi-Fi file transfer, Calibre/OPDS workflows, and KOReader progress sync — features the stock firmware doesn't have.

Sources: crosspoint-reader/crosspoint-reader · XTEINK X4 official product page

Stay on stock if you need Bluetooth — it's the only firmware in this scene that ships it. None of the custom reader firmware ships Bluetooth, though a couple of forks like CrumBLE add a BLE page-turner remote back. If you mainly want better EPUB rendering, fonts, and wireless transfer, that's exactly what flashing buys you.

Sources: XTEINK X3 product page (stock Bluetooth) · CrumBLE README (BLE page-turner)

On an unlocked unit, yes — re-flash the latest official firmware from the CrossPoint web flasher, and you can save a full-flash backup over USB beforehand so most bad flashes are a quick fix. On a locked unit there's no USB safety net (the backup runs over USB, which is what's blocked), so keep a stock update.bin on your SD card as your rollback instead.

Sources: CrossPoint README (revert to official firmware)

First find out if your device is locked: plug it in over USB in desktop Chrome or Edge (Safari is not supported; Firefox is inconsistently documented) and see if the web flasher detects it — if it never appears, treat it as locked. If it's unlocked, save a full-flash backup first; if it's locked, stick to CrossPoint or CrossInk, the only two firmwares the OTA Unlocker supports.

Sources: CrossPoint flasher / browser support · CrossPoint OTA Unlocker (CrossPoint + CrossInk only)

Yes, with the right firmware. On a locked X3 the SD-card method works directly from stock: copy update.bin to the SD root and hold the left-side button + power so the OEM bootloader flashes it. On a locked X4 the reliable entry from stock is the CrossPoint OTA Unlocker (a local Wi-Fi hotspot that serves CrossPoint/CrossInk during the device's update check) — the X3 SD button-trick doesn't reliably engage from X4 stock; it doesn't brick, it just doesn't fire. Once CrossPoint is on, in-app SD updates work for the future. The lock is reported to be a hardware eFuse on some X4 batches, but the mechanism is unconfirmed and may vary, and SD/OTA flashing never re-enables USB.

Sources: CrossPoint PR #1786 (SD update + X3 bootloader) · CrossPoint OTA Unlocker · trilwu/crosspet #28 (eFuse reports)

Yes, if you flash the wrong firmware on a locked unit. Only CrossPoint and CrossInk are officially supported there; the CrossPoint README warns that flashing anything else on a USB-locked device may permanently brick it or leave it stuck on that firmware with no recovery path. Papyrix removed OTA support, so an owner was left unable to reflash after installing it (issue #120), and CrossPet became a one-way door — owners couldn't switch or revert (issue #28). Microreader, AvesO3, inx, and experimental forks carry the same risk.

Sources: CrossPoint README (officially supported firmwares) · bigbag/papyrix-reader #120 (unable to reflash) · trilwu/crosspet #28 (one-way door)

XTEINK has added flashing restrictions to recently shipped units and publicly discourages third-party firmware (citing crashes and even screen damage), so treat custom firmware as unsupported by the vendor — there's no verified vendor warranty position beyond that. Flashing writes to the device's chip and doesn't touch your microSD card, so your EPUBs on the card stay put; you can also wipe CrossPoint's cached metadata anytime by deleting the /.crosspoint folder on the card.

Sources: Good e-Reader: XTEINK to block custom software · CrossPoint README (/.crosspoint cache)

For most owners the answer is CrossPoint Reader: it is the open-source mainline (MIT, C, ~5.4k GitHub stars — a volatile counter — currently v1.3.0), it runs on both the X3 and X4, and it is one of only two firmwares the OTA Unlocker officially supports, so it is the safe default on a locked unit too. It covers EPUB 2/3, .txt, .bmp and the native .xtc/.xtch format, with Wi-Fi transfer, Calibre/OPDS, custom SD-card fonts and a standalone SD-card update path (added in v1.3.0). Note it does not render PDF, by design.

Sources: crosspoint-reader/crosspoint-reader · CrossPoint flasher / install

CrossInk is a CrossPoint fork (also MIT, confirmed working on X3 and X4) that adds typography and reading-tracking extras: reading statistics, Bionic Reading and Guide Dots, three e-ink-tuned fonts (ChareInk, Lexend Deca, Bitter), a synthetic-glyph fallback for missing characters, and stats-as-sleep-screen. Pick plain CrossPoint if you want the most-supported base; pick CrossInk if you specifically want the stats and typography features — and either is fine on a locked device, since these are the only two firmwares the OTA Unlocker serves.

Sources: CrossInk firmware fork · crosspoint-reader/crosspoint-reader

Most of these firmwares ship without Bluetooth — it's left out to free RAM for reading features — though a couple of forks like CrumBLE (BLE page-turners) and SUMI (BLE keyboards/page-turners) add it back. You also can't render PDFs on CrossPoint (no PDF rendering, by design). Otherwise custom firmware generally adds capability — more formats, fonts, Wi-Fi transfer, Calibre — rather than removing it.

Sources: crosspoint-reader/crosspoint-reader · psychoplath9450/SUMI (BLE features)

Go to a fork only for a feature the mainline doesn't have: CPR-vCodex (developed and validated on X4; X3 is user-reported, not maintainer-tested) for reading streaks/analytics, StarDict dictionary and flashcards; Papyrix for FB2 / Markdown / TXT / HTML and RTL libraries; SUMI for an offline-only device with sandboxed Lua plugins, 20 built-in apps and Bluetooth; Microreader (X4-only) for a minimal, do-one-thing EPUB reader. Each is a single-feature trade, so only switch if you'll actually use that feature.

Sources: CPR-vCodex README · bigbag/papyrix-reader · psychoplath9450/SUMI

On a locked unit, stick to CrossPoint or CrossInk: those are the only two the OTA Unlocker officially supports, and flashing anything else on a locked device may permanently brick it or leave you stuck on that firmware with no recovery path. Avoid forks with no OTA and no standalone SD update.bin here — Papyrix is marked 'avoid' on locked units (SD-flashable but no OTA way back), base Microreader and AvesO3 warn unlocked-only, and a CrossPet owner reported being permanently stuck after flashing it onto a locked X4. (Vcodex installing directly on a locked X4 via SD is community-reported only, not maintainer-documented, and unverified on X3.)

Sources: CrossPoint Unlocker (locked-device support) · crosspoint-reader/crosspoint-reader · Papyrix: stranded locked-X4 report (#120)

The only firmware with a genuine on-device scriptable plugin system is SUMI, which runs sandboxed Lua 5.4 scripts dropped into /custom/ on the SD card as launchable apps, plus 20 built-in apps. Don't reach for PlusPoint for this — despite older descriptions, it's an experimental C++ OS proof-of-concept for the X4, not a user-installable-JavaScript-apps platform. Note SUMI is offline-only (no Wi-Fi) and installs over USB only, so it's not a safe pick for a locked device.

Sources: psychoplath9450/SUMI

There's no reliable way to tell from the box, so the only sure test is to plug into USB in Chrome or Edge and see whether the CrossPoint web flasher detects the device. A locked unit never enumerates as a USB serial port, so neither the web flasher nor the esptool CLI can see it. Buying direct from xteink.com or Amazon is usually unlocked but not guaranteed (a unit received directly from XTEINK was reported as locked), and the "overseas units are exempt" claim is not established. If the device never appears over USB, treat it as locked.

Sources: CrossPoint README - USB-locked devices · trilwu/crosspet #28 - device never enumerates as serial port · CrossPoint #2029 - locked unit received direct from XTEINK

On a locked X3 the SD-card method works directly from stock: copy update.bin to the SD root and hold the left-side button + power, and the OEM bootloader flashes it (the OTA Unlocker also works). On a locked X4 the reliable entry from stock is the CrossPoint OTA Unlocker, which turns your computer into a local Wi-Fi hotspot that serves CrossPoint or CrossInk during the device's update check. The CrossPoint maintainer could not find an X3-style SD button-trick that engages from X4 stock - it doesn't brick the device, it just doesn't engage. Once CrossPoint is on, the in-app SD System Update works for future flashes.

Sources: CrossPoint PR #1786 - X3 SD bootloader path & X4 NVS flag · CrossPoint Unlocker - hotspot serves CrossPoint/CrossInk · trilwu/crosspet #28 - in-app SD update on locked X4

Stick to CrossPoint or CrossInk - they're the only two firmwares the OTA Unlocker officially supports, and both ship an in-app SD-card update as a way back. The README warns that flashing any other firmware on a USB-locked device can permanently brick it or leave it stuck on that firmware with no recovery path.

Sources: CrossPoint README - only CrossPoint & CrossInk supported · CrossPoint Unlocker - serves CrossPoint/CrossInk

Avoid forks that have no OTA way back - they can strand a locked unit. Papyrix has an SD update/recovery path but no OTA, so the README itself says to flash it only on devices with unlocked USB; an owner was left stranded after putting it on a locked X4. CrossPet is worse: owners report being permanently stuck on it, unable to switch or revert. Microreader, AvesO3, inx, PlusPoint and other experimental forks carry the same stranding risk on a locked unit.

Sources: trilwu/crosspet #28 - owners stuck on CrossPet, no exit · bigbag/papyrix-reader #120 - stranded after Papyrix on locked X4 · bigbag/papyrix-reader - flash only on unlocked USB

Owners describe some grey-market X4 batches as having the ESP32-C3 USB serial mode permanently disabled ("eFuse burned"), and a CrossPoint developer found USB stayed dead even after SD-flashing - but the exact mechanism is unconfirmed, not vendor-stated, not yet verified by teardown, and may vary by batch. Either way, neither SD nor OTA flashing re-enables USB: the Unlocker explicitly does not restore USB flashing, so you get custom firmware but the USB port stays locked.

Sources: trilwu/crosspet #28 - eFuse-burned owner reports · CrossPoint PR #1786 - USB dead after SD flash; planned teardown · CrossPoint Unlocker - does not unlock USB flashing

No - the web flasher's full-flash backup runs over USB, which is exactly the route the lock blocks, so you can't make one. Instead keep a stock update.bin on the SD card as your rollback, and stay on CrossPoint or CrossInk so the in-app SD update gives you a way back. On a no-OTA fork there may be no recovery at all.

Sources: CrossPoint README - locked no-recovery warning

First make sure the device is awake and sitting at the home screen (not asleep) and that you're using a USB-C cable that supports data, not a charge-only cable. If it still never appears in Chrome or Edge, your unit is most likely USB-locked — connecting in the flasher and seeing whether it's detected is the only sure test for the lock — and you'll need the SD-card method (X3) or the OTA Unlocker (X4) instead.

Sources: crosspointreader.com · CrossPoint README

Use desktop Chrome or Edge — they reliably support the WebSerial API the flasher relies on. Firefox is inconsistently documented (the official site lists it in one place and omits it in another), and Safari is not supported. You also need a USB-C cable that actually carries data; a charge-only cable will not work.

Sources: crosspointreader.com · CrossPoint README

Yes — if you're coming from stock or another firmware, you may need to run the flash twice before CrossPoint actually shows up. Just repeat the same web-flasher step.

Sources: crosspointreader.com

Press the Reset button, then press and hold the power button for 3-5 seconds to boot it. If your unit is running CrossPoint 1.3.0 or newer, you can also force the SD recovery path by holding the UP button (the top-left button on the X3) + power at startup, which skips the home screen and jumps straight into the SD firmware picker.

Sources: crosspointreader.com · CrossPoint PR #1786

Most likely it's USB-locked rather than bricked: the lock blocks only the USB serial route, while the SD-card and OTA update paths still work. On a locked X3, copy update.bin to the SD root and hold the left-side (top-left) button + power — the OEM bootloader flashes it directly from stock. On a locked X4 the reliable route from stock is the OTA Unlocker (a local Wi-Fi hotspot that serves CrossPoint or CrossInk during the device's update check); the X3 SD button-trick doesn't reliably engage on a stock X4. Stick to CrossPoint or CrossInk — those are the only two the Unlocker supports.

Sources: OTA Unlocker · CrossPoint PR #1786 · CrossPoint README

On an unlocked unit, open the web flasher and use 'Save full flash' to copy your current firmware (about 25 minutes); if a flash fails you can load that file back, so most 'bricks' are a quick fix. A locked unit can't do this because the backup runs over USB — the exact route the lock blocks — so keep a stock update.bin on an SD card as your rollback instead.

Sources: CrossPoint README (USB-locked devices)

Not directly. CrossPoint's reader engine handles EPUB 2/3, the native .xtc/.xtch formats, .txt, and .bmp, but PDF rendering is explicitly out of scope. The workaround is to convert the PDF to the device's .xtc format first using a web tool like xtcjs, which turns PDFs, CBZ comics, images, and even video into XTC optimized for the X4 and X3.

Sources: crosspoint-reader (supported formats) · varo6/xtcjs (PDF/comic to XTC converter)

Base CrossPoint reads EPUB, .xtc/.xtch, .txt, and .bmp only. If you need FB2, Markdown (.md), or HTML, the Papyrix fork adds all three (plus plain text) on top of EPUB and the native XTC formats. Just note Papyrix has no OTA updates: its own README says to flash it only on devices with unlocked USB and to keep an SD recovery card, so most owners avoid it on a USB-locked unit.

Sources: bigbag/papyrix-reader (FB2/Markdown/HTML support, no OTA warning)

Base CrossPoint does not have purpose-built CJK; for that you flash a dedicated fork. CrossPoint CJK is X4-only and gives you a Chinese/Japanese/English interface plus CJK rendering (it loads fuller fonts from a /fonts/ folder on the SD card). For Korean, CrossPoint KO runs on both X3 and X4. Papyrix also lays out CJK book text (but not its own UI) on both devices.

Sources: aBER0724/crosspoint-reader-cjk (X4-only, CJK fonts) · crosspoint-reader-ko (X3 + X4) · bigbag/papyrix-reader (CJK book-text layout)

RTL is supported: base CrossPoint lists RTL support, and Papyrix does full Arabic shaping (contextual forms, Lam-Alef ligatures, RTL layout) plus Thai. Hindi/Devanagari is not a documented supported script on any of these firmwares; it's an open question users have raised in the r/XTEINK community, so treat it as not reliably working today.

Sources: crosspoint-reader (RTL support) · bigbag/papyrix-reader (Arabic shaping, RTL) · r/XTEINK: rendering Devanagari/Hindi EPUBs

Those are missing glyphs the font doesn't cover. The CrossInk fork added a synthetic-glyph fallback (PR #104) that procedurally draws missing Unicode characters that would otherwise display as replacement diamonds or collapse into whitespace, covering things like block redactions, Greek letters, and the turned comma. It adds about 2.1 KB to flash and leaves RAM usage unchanged.

Sources: CrossInk PR #104 (render missing Unicode glyphs)

Yes. On CrossPoint you convert TTF/OTF into .cpfont files at crosspointreader.com/fonts and load them from /fonts/YourFont/ on the SD card with no reflash; you can also download them on-device via Settings > System > Download Fonts. On the CJK fork, fuller fonts live in a /fonts/ folder on the SD card, but the ESP32-C3 has very limited RAM, so the docs warn that using large CJK fonts for both the UI and reading at once can cause out-of-memory crashes, and recommend keeping UI fonts at 20pt or below.

Sources: crosspoint-reader (custom .cpfont fonts) · aBER0724/crosspoint-reader-cjk (SD fonts, memory limits)

No. Flashing replaces the device firmware, not the contents of the SD card where your books, fonts and cached metadata live. If you do want to clear cached metadata on CrossPoint, deleting the /.crosspoint folder forces a full cache regeneration on next open, but your book files are untouched.

Sources: CrossPoint README (cache regeneration)

On an unlocked X3/X4, yes: open the web flasher and click 'Save full flash' to copy your current firmware (~25 minutes) so you can load it back if a flash goes wrong. A locked unit can't do this because that backup runs over USB, which is exactly what the lock blocks; instead keep a stock update.bin on the SD card as your rollback.

On an unlocked device, re-flash the latest official firmware from the CrossPoint web installer at crosspointreader.com/#flash-tools. On a locked unit you have no USB route, so your rollback is to keep a stock update.bin on the SD card: a locked X3 flashes it directly via the OEM bootloader (left-side button + power); on a locked X4 the OTA Unlocker is the reliable entry from stock, and once CrossPoint is on, in-app SD updates work for future changes.

Sources: CrossPoint repo (revert via web flasher / SD update + X3 bootloader)

On an unlocked device you can re-flash freely over USB. On a locked device, switching only works if your current firmware exposes an SD-card update path and the fork you want ships a complete standalone update.bin for your model — CrossPoint and CrossInk do (Vcodex is community-reported on X4 only, not maintainer-documented). Once CrossPoint is installed, its in-app SD System Update lets you switch among SD-flashable forks.

Sources: CrossPoint PR #1786 (SD-card firmware update + X3 bootloader)

CrossPet is the worst case: it has no in-app SD update and ships no standalone update.bin, so owners report being permanently stuck on it on a locked (eFuse) X4 — the web flasher, Unlocker hotspot and Power+Up bootloader all fail, and the proposed SD-flash fix (PR #29) is still open and unmerged. Papyrix removed OTA entirely, so on a locked unit it leaves no OTA way back. The OTA Unlocker officially supports only CrossPoint and CrossInk; flashing anything else on a locked device may permanently strand it.

Sources: CrossPet issue #28 (one-way door, recovery routes fail) · CrossPet PR #29 (SD-flash fix, open/unmerged) · CrossPoint README (only CrossPoint/CrossInk supported)

After a CrossPoint flash, press the Reset button, then press and hold power for 3-5 seconds to boot. If it still won't start: on Papyrix, copy the firmware as /force_update.bin to the SD card and the device auto-flashes it on next boot. On an unlocked unit you can also re-flash over USB from the web installer. On a locked unit your only safety net is an SD card with a working update.bin, since USB recovery is blocked.

Sources: crosspointreader.com (reset + hold power to boot) · Papyrix README (force_update.bin auto-recovery)

The X3 has a smaller 3.7-inch panel at 528x792 (259 PPI); the X4 has a larger 4.3-inch panel at 480x800 (220 PPI). Both run the same ESP32-C3 chip, which is why they share the community flashing ecosystem and most firmware. The biggest practical day-to-day split is the charging cable (see below).

Sources: crosspointreader.com (panel resolutions) · XTEINK X3 product page · XTEINK X4 product page

No. The X3 charges over a proprietary magnetic pogo-pin cable (included in the box), while the X4 charges and connects over standard USB-C and ships with no cable. To flash the X4 over USB you'll need a USB-C cable that supports data transfer, not a charge-only one.

Sources: XTEINK X3 product page (Magnetic Pogo Pin) · XTEINK X4 product page (USB Type-C, no cable) · CrossPoint README (data cable required)

CrossPoint and CrossPoint KO run on both the X3 and X4. Microreader, inx, and CrossPoint CJK are X4-only and do not support the X3. AvesO3 targets the X4 (X3 support is unverified) and requires an unlocked device. So X3 owners can't run the X4-only forks.

Sources: Microreader (X4 only) · inx (X4 only) · CrossPoint KO (X3 and X4)

It's an X3-only feature, both on XTEINK's stock firmware and in CrossPoint, whose README marks tilt page-turn 'X3 only'. The X4 has a gyroscope sensor but doesn't list shake-to-turn.

Sources: CrossPoint README (Tilt page turn X3 only) · XTEINK X3 product page (Shake-to-turn-page)

No, the rescue paths differ. On a locked X3 the SD-card update.bin method works directly from stock: copy update.bin to the SD root and hold the left-side button + power; the OEM bootloader flashes it. On a locked X4 the reliable entry from stock is the CrossPoint OTA Unlocker (which serves CrossPoint or CrossInk). The X3 SD button-trick is not a reliable path from X4 stock — the CrossPoint maintainer couldn't find a stock-to-custom SD key-combo on the X4 (the NVS 'activate' flag is 0 on X4 stock vs 1 on X3). It doesn't brick; it simply doesn't engage. Once CrossPoint is installed on the X4, the in-app SD update works for future flashes.

Sources: CrossPoint PR #1786 (SD update + X3 bootloader compatibility) · crosspointreader.com (SD update.bin steps) · CrossPoint OTA Unlocker

On a locked unit there's no USB safety net: the device doesn't enumerate over USB, so you can't read or rewrite the flash to recover. The mechanism is reported to be a burned eFuse that permanently disables the ESP32-C3 USB serial route on at least some grey-market X4 batches, but it isn't vendor-confirmed and may vary by batch; SD/OTA flashing does not re-enable USB. So on a locked unit, stick to CrossPoint or CrossInk (the only two the OTA Unlocker serves) and keep a stock update.bin on the SD card as your rollback. Avoid forks with no OTA and no standalone SD image — CrossPet, for example, has stranded locked X4 owners who could no longer switch or revert.

Sources: crosspet issue #28 (eFuse burned, no serial port; owners stuck) · CrossPoint PR #1786 (USB-lock discussion)

Custom XTEINK firmware drops Bluetooth to free memory for reading features, so none of the firmware in the standard chooser ships it. If you need Bluetooth, stock is the only firmware in that guide that has it; a couple of community forks (notably CrumBLE) have added a Bluetooth page-turner back.

Yes. CrumBLE, a personal CrossInk fork for the X4 (X3 in development), adds real BLE support and pairs BT HID remotes like the IINE GameBrick or Free2 as a wireless page-turner. SUMI also supports Bluetooth LE 5.0 page turners (and BLE keyboards) on both X3 and X4. On CrumBLE you pair from inside an open book, and BLE auto-disables when you leave the book, so you reconnect each time you open a new one.

Sources: CrumBLE README · SUMI repo

The only genuine on-device scriptable-plugin firmware is SUMI, which has a sandboxed Lua system: drop a .lua file in /custom/ on the SD card, restart, and it appears in the Apps list (the Lua VM is capped at 40KB memory and 100K instructions per call). SUMI also ships 20 built-in apps including a dictionary, flashcards, and games. Base CrossPoint deliberately has no plugin system or app store — its scope doc rules out apps like notepads, calculators, and games.

Sources: SUMI repo · CrossPoint SCOPE.md

No. PlusPoint is an experimental pure-C++20 OS proof-of-concept for the X4 only, whose author says the goal isn't a usable firmware; it has no JavaScript engine, no app launcher yet, and ships only via PlatformIO from source. For a real on-device plugin system, use SUMI (Lua), not PlusPoint.

Sources: PlusPoint README

Yes. SUMI does offline word lookup from StarDict dictionaries dropped into /dictionary/<name>/, with fuzzy matching and word-stemming. CrumBLE and Vcodex also add StarDict dictionary lookup from the SD card.

Sources: SUMI repo · CrumBLE README · Vcodex README

Calibre is the standard free ebook manager, and CrossPoint has a Calibre wireless plugin that uploads EPUBs over WebSocket (auto-discovered on your network) and can optimize images for the screen first. For DRM-free books, Project Gutenberg and Standard eBooks read on both stock and custom firmware. For comics and PDFs, a browser converter like xtcjs turns them into XTEINK's XTC format; the epubkit web tool optimizes EPUB images for e-ink. Note stock firmware doesn't render images inside EPUBs at all, so image optimization mainly benefits custom firmware like CrossPoint/CrossInk.

Sources: CrossPoint Calibre plugin · epubkit · xtcjs