Snail OS — Custom Firmware for the XTEINK X4<br>A letter<br>Snail exists to protect calm, intentional computing.<br>We make small e-ink computers people can reach for when they want to read, think, learn, explore, communicate, or understand their day without opening the full firehose of a phone.<br>Snail should feel like magic because it is simple, useful, quiet, and deliberately constrained.<br>Snail is the small e-ink computer for the in-between moments. Five minutes before the next work call. A thirty-minute lunch walk. Coffee in the morning. A couple of hours on the porch. The beach. The pool. A waiting room. The quiet part of an evening.<br>The phone is not the enemy. It is simply not the best computer for every moment.<br>Snail OS is the first thing we ship: an operating system for the XTEINK X4, a $40 e-reader with a 4.26-inch panel, Wi-Fi and a microSD slot. It reads books, keeps a clock and a calendar, forecasts the weather, reads the web as plain text, receives pages, and installs more apps over Wi-Fi. I reverse engineered the board and wrote the display driver from the datasheet.<br>Why Snail? Because these beautiful devices magnet to the back of your phone (the Slug), and snails are cute.<br>Joey Smith<br>Founder

Buy the firmware — $2.99

Buy a device — $139

Snail OS version 1<br>Firmware 1.53 · XTEINK X4<br>The launcher

Read

Clock

Weather

Store

Snake

Blackjack

Details<br>FeaturesFeatureSnail OSOEM firmwareCrossPointDisplay driverHow the panel is driven.Snap Display, our own driver. Blacks are blacker, fonts are crisper, and refreshes are incredibly fast.Vendor waveform.Vendor waveform via GxEPD2.Partial refreshTime to repaint part of the screen.123 ms with Snap Display; 499 ms with the factory waveform.~499 ms, the vendor's timing.Not timed by us.Full refreshTime to repaint the whole screen.~1.7 s.~3.8 s stock waveform.~1.7 s.ReaderFormats and features.EPUB and plain text, cover on the shelf, reading-progress sync, text size and justification as settings.EPUB, TXT.EPUB, hyphenation, dictionaries, reading-progress sync.Web browserThe open web on the panel.Plain-text browser; every page kept on the card.——App storeInstall software after purchase.Store installs card apps over Wi-Fi from the published catalogue. A card app is one Lua file you can read and edit.——Create your own appsDescribe one to an AI agent.Snail ships Claude Code and Codex skills. Let your creativity run wild; the OS and SDK provide networking, UI and button mappings.——Snail ConnectAccounts you connect once.GitHub, Analytics, Search Console, Calendar and Congress; sign in by scanning a code. The device holds a read-only token.——PageMessages from your AI agents.Receive and answer pages from your AI agents with the buttons. Inbox cached on the card.——Wi-FiNetworking.Scan, join, remember; Drive moves files on and off the card; Store, Weather, Browser, Connect and Page use it.File transfer.Book upload over the browser, OTA.BluetoothRadio.Present; unused by Snail OS v1.——Clock · Calendar · WeatherBuilt in.Three clock faces. Month grid to day to event. Six-day and twelve-hour forecasts.——GamesOn the card.Snake, Blackjack, and whatever the Store lists.——Original firmwareWhat happens to it.Kept. Snail OS goes in the spare slot; revert is one command.Is the original.Overwrites the boot bank.SourceSold, unpublished. Card apps are readable in full before install.Closed.Open, GPL, on GitHub.Price$2.99, one person, every X4 you own.Included with the X4.Free.SupportHuman support, like any great consumer product. Email and a person answers.XTEINK.GitHub issues.

Device specsDeviceXTEINK X4SoCESP32-C3 · RISC-V · single core · 160 MHzMemory~400 KB SRAM · 16 MB flashDisplay800 × 480 · 1-bit e-ink · portraitInputSix buttons plus powerStoragemicroSDRadioWi-Fi + Bluetooth LEInterface480 × 800 portrait · Ubuntu Mono · 1-bitVersion1.53<br>What you getSnail OS download · $2.99<br>The firmware, built and ready to flash onto an X4 you already own.<br>You get<br>Snail OS, its apps and the Store<br>The installer and the revert tool<br>A key that re-downloads it any time<br>You need<br>An XTEINK X4<br>A computer and USB-C cable<br>A few minutes<br>Your download link and key are emailed the moment you pay.

X4 with Snail OS · $139<br>An XTEINK X4 with Snail OS installed and tested on the device. Limited to 1,000 devices.<br>You get<br>XTEINK X4<br>Snail OS installed<br>Device tested before shipment<br>You need<br>Nothing else<br>Charged at checkout, shipped October 1, 2026. Refundable in full until it goes out.

Buy<br>Buy the firmware — $2.99

Buy a device — $139

Firmware: Your download link and key are emailed the moment you pay.<br>Device: Charged at checkout, shipped October 1, 2026, refundable in full until it goes out. Limited to 1,000. Ships to the United States.

Snail OS is firmware for the XTEINK X4, sold as a download. The device tier is an XTEINK handheld purchased at retail, flashed with Snail OS and tested before shipment; the model may vary with availability, X4 or X3. Sold as is, without warranty; see the terms. Refunds: email...