The £40 Xteink X4: a pocket e-ink reader that custom firmware makes worth owning

The Xteink X4 is a tiny, ultralight e-ink reader that sells for around £40 and is marketed on the gimmick of magnetically sticking to the back of a phone. In practice the phone-mount angle underwhelms (third-party MagSafe cases mount it inverted, and the spot is often already taken), but the real selling point is size: it genuinely vanishes into a trouser pocket while still showing crisp text with instant, ghost-free page turns. The stock firmware is serviceable but barebones — a handful of fonts, basic spacing controls, EPUB only — which sells the decent hardware short.

The device’s appeal comes from a small open-source firmware scene, all forked from CrossPoint, which now ships OTA updates, 24 UI languages, and a browser-based flasher. Units sold outside China have USB flashing disabled, but an SD-card flashing method works around that. The author tried Papyrix (minimal, with a surprisingly sophisticated Knuth-Plass typography engine and multi-script support) before settling on Inx, the most polished option, offering per-book settings, Calibre and KOReader sync, OPDS browsing, and detailed reading statistics. The rabbit hole runs deeper still: MicroSlate turns it into a Bluetooth-keyboard writing slate, TernOS is a PalmOS-inspired Rust/Palm app environment, and odds and ends include an MQTT Tamagotchi companion and a local wallpaper converter.

The broader point is a hardware-versus-software one. Compared to colour e-ink tablets running Android — flexible but bogged down by phone-OS bloat, lag, and immature colour panels — the X4 wins by being smaller and dumber in the best way. For pure reading, the author argues, pocketability beats colour, and community firmware transforms a cheap, throwaway-feeling gadget into something genuinely good.