Programming the RP2040 MCU

To upload a new firmware image on the PR2040 (the “pico” part of “pico-ice”), you need to switch to that RP2040 UF2 bootloader mode instead of the FPGA UF2 mode.

You can do that by connecting a jumper between the BT pin a Gnd pin, then press the RESET button:

1. Connect the USB_BOOT pin to ground. For instance with a pair of tweezers, a jumper, or an uncoated paper clip.

2. Press and release the “RESET” button. The RP2040 now bypasses its firmware, and runs the RP2040 factory bootloader (from internal ROM) instead.

3. Disconnect the USB_BOOT pin from ground.

4. Look for an USB drive named RPI-RP2 and mount it, open it, and check that there are only 2 files in it: INFO.HTML and INFO_UF2.TXT. If you also have an CURRENT.UF2, this means you found the FPGA flashing interface, and need to retry steps 1 and 2.

5. Copy the .uf2 firmware file onto the USB drive.

6. Eject the USB drive. At this step, the firmware should be uploaded and running.

Troubleshooting

RPI-RP2 is still visible after step 6

This means the device remained in “bootloader” mode. One thing to check is that the USB_BOOT pin (marked BT on the board) is not connected to anything anymore, then try to reset the board.