
Pico comes without any firmware flashed.
Installation:
Plug USB-C into computer
Drag and drop .uf2 onto the root of the "RPI-RPI2" disk
Solder 5 wires to the Gamecube, following the instructions
Updates:
Set pin jumper
Plug USB-C into computer
Drag and drop .uf2 onto the root of the "RPI-RPI2" disk