Use Chrome or Edge on a desktop, with this page served over HTTPS or localhost. The list includes only connected devices you have authorized for this site; use “Choose USB device” to authorize another. The chooser lists devices independently of the display filter above.

For RP2350 / RP2040 boards, try holding BOOT while connecting a data-capable USB cable, then choose the bootloader device. The board must enumerate over USB, and its firmware must expose a serial descriptor. Bootloader and application serial numbers can differ. For a DDX firmware license, verify that this USB serial matches the serial reported by the DEMO firmware; use the firmware serial if they differ.

Browser and operating-system restrictions may hide some devices. WebUSB cannot reproduce the full system USB inventory or show a USB location or tty/COM path. No serial port is required.