Flash it in your browser

Writes straight to the board over USB. Works in Chrome or Edge on Windows, Mac, Linux, or ChromeOS — not on phones/tablets, and not in Firefox or Safari (they don't support the Web Serial API this depends on).

Your browser doesn't support this — open this page in Chrome or Edge on a computer instead. This page needs to be loaded over HTTPS for the browser to allow it.
Updating to a new version keeps everything you've already set up — Wi-Fi, your chess.com/Lichess/ChessConnect connection, sound and LED settings — none of that gets touched. If you'd rather start completely fresh (e.g. before giving the clock to someone else), the installer offers an "erase device" checkbox before it writes anything - leave it unchecked for a normal update.

What's next

The firmware is running — now it needs a Wi-Fi network and a chess.com, Lichess, or ChessConnect connection to actually show anything.