Download the latest .uf2 firmware file from the repository Releases
Unprogrammed Units: Connect to a host computer with the USB cable.
Programmed Units: If the unit has been programmed before, it is required to hold down the button on the back of the device while plugging it into the host computer. Once plugged in, the button can be released.
An external Drive RPI-RP2 should appear
Click+Drag the desired firmware .uf2 file into the RPI-RP2 drive.
Once the file transfer is complete, the unit will be running the new firmware.