Use the flash_nuke.uf2
R2P2 formats part of the flash ROM as a storage device during its first startup and generates the directories and files necessary for the system. This process sometimes fails, causing R2P2 to become uncontrollable or behave strangely.
If this happens, download flash_nuke.uf2 from the page below and install it on the RPI-RP2 (for Pico) or RP2350 (for Pico2) drive that shows at reboot with BOOTSEL button.
https://www.raspberrypi.com/documentation/microcontrollers/pico-series.html#resetting-flash-memory
Since the microcontroller’s ROM will be zero-cleared, install R2P2 again.
Even in cases other than the above, if you feel that the ROM has become corrupted, use flash_nuke.uf2 to initialize the microcontroller.