Install Snail OS.

Almost always the cable. Many USB-C cables carry power and no data, and a charging cable looks identical to a data one. Try a different cable before anything else.

Then check the X4 is switched on — hold the side button about three seconds. A device that is off does not appear.

You clicked install.ps1. Click Install Snail OS (Windows).bat instead — that is the one meant for double-clicking.

Same fix: use the .bat file. It runs the installer in a way that applies to that one window and changes no setting on your computer.

Install Python from python.org/downloads. On Windows, tick Add python.exe to PATH in the installer — it is easy to miss and nothing works without it.

Then open a new terminal (or PowerShell) and run pip3 install esptool, and run the installer again.

The installer writes the spare bank and the 8 KB that selects which bank boots. It never writes the bank your original firmware is in.

Your original firmware is never overwritten. It sits in the first flash bank; Snail OS goes in the second, unused one. Installing changes which of the two boots.

Yes, with one command — see “Going back” above. It rewrites the boot record only, and the original firmware comes back exactly as it was, because it was never touched.

That is expected on this hardware, not a failure. The USB port is part of the chip, so the reset at the end of a flash takes it off the bus. Hold the side button about three seconds to power it back on.

Copy .epub or .txt files into a books folder on the microSD card. The reader lists everything it finds.

You can also send them over Wi-Fi: open the Drive app, and it shows an address to open in your browser and a four-digit code.

No. The device works without one, with less on it. The card is what holds books, the games you install, and your saved Wi-Fi.

It is encrypted with a key derived from your device's own chip, so the card alone does not open it. Books and apps on the card stay as plain files you can read and copy.

Yes. Snail OS is running on real XTEINK X4 hardware. The display driver, buttons, SD card, Wi-Fi and included apps have been built and tested on the device.

No. The X4 has two firmware slots; Snail OS goes into the unused one and the original stays in the other. The slot holding your original firmware is never written.

No. Installation is done over the USB-C port.

A 4.26-inch e-ink handheld built around an ESP32-C3 with about 400 KB of RAM, 16 MB of flash, Wi-Fi, Bluetooth LE, microSD, six buttons and an 800 × 480 monochrome display.

A shipped firmware image carries nobody's network password, so a fresh install starts unjoined. Open the Wi-Fi app once, pick your network and enter the password with the buttons. The SD card keeps it and the device rejoins on every boot.

No. During a download the panel lends its memory to the transfer, so the screen holds still until the install finishes or fails, then says which.

In order: the signal bars in the header (join in the Wi-Fi app if missing), the clock (open Clock and press OK after a dead battery), and the pairing (the app's sign-in screen cures a token minted before a feature existed - OK makes the QR code).

No. Networked apps make requests when you use them; the OS does not report usage in the background.

CrossPoint is primarily an e-book reader for the X3 and X4. Snail OS treats the X4 as a small general-purpose e-ink computer: reading is one app alongside a clock, weather, a text-only browser, networking, utilities and games.

Yes. A card app is one Lua file in /apps on the SD card — the launcher finds it and lists it with its own name and icon, no reflash. The Store app on the device installs published ones over Wi-Fi. The built-in apps are compiled into the firmware, so a new one of those still means a new build from me. See the developer documentation at snailos.org/dev.

No. The download is already built. You join a Wi-Fi network on the device itself — the Wi-Fi app scans, you type the password with the buttons, and it is saved to the SD card. Nothing is baked into the firmware.

EPUB or plain text on the microSD card. The reader imports an EPUB on the device and draws its cover on the shelf. Drive moves files onto the card over Wi-Fi, or you can put the card in a computer. PDF is converted by a host tool first.

$2.99 for the download, which is emailed to you at checkout. A prepared SD card is $85 and an X4 with Snail OS installed is $139; both are charged at checkout and ship October 1, 2026, refundable on request until they go out.

No. Snail OS is a commercial product and the source is not distributed. The download includes the third-party components the firmware uses, with their licences and required notices.

A zip with the Snail OS firmware already built, the installer, the revert tool and the instructions. The email carries the download link and your key.

Yes. Pay $2.99 and the email with your download link and key arrives within a minute. Unzip it, plug the X4 into your computer and run the installer.

Email joey@snailos.org. A download is refunded if Snail OS will not run on your X4; a card or device is refunded in full any time before it ships.