Use desktop Chrome or Edge. The installer needs Web Serial, which is only available in those browsers on a computer. Phones and other browsers cannot open the board.
If it doesn’t connect
Most boards flash with no buttons pressed. They reset on their own.
- Stuck on “Connecting”, or it won’t connect? Hold BOOT, click Install and pick the port, then release BOOT once flashing starts.
- No port in the list? Try another USB cable that carries data, and install the CH340 or CP210x driver.
- If the screen doesn’t refresh afterwards, press RESET, or unplug the board and plug it back in.