120 ohm Termination Resistor

There is a permanent 120 ohm termination resistor soldered to the board, no need to add a jumper to enable it and also no ability to disable it.

Flashing UTOC Firmware

This information is from https://mellow-3d.github.io/fly-utoc_firmware.html#flashing-utoc-firmware

Note: The UTOC firmware is intalled at the manufacturer. This procedure is only needed to restore the OEM firmware.

Download the stock firmware from https://mellow-3d.github.io/files/utoc_firmware.bin and copy it to the user folder on your Pi.

Install the DFU mode Jumper



Connect the UTOC to your Pi by the USB C port

On your Pi run the command:


If it shows something like:

Bus 001 Device 004: ID 0483:df11 STMicroelectronics STM Device in DFU Mode

With the ID of the DFU device as 0483:df11, then run the following command to flash the UTOC.

sudo dfu-util -d 0483:df11 -c 1 -i 0 -a 0 -s 0x08000000 -D ~/utoc_firmware.bin

Otherwise if it shows something like:

Bus 001 Device 004: ID 314b:0106 Geehy APM32 DFU ISP Mode

With the DFU device ID as 314b:0106, run this command instead:

sudo dfu-util -d 314b:0106 -c 1 -i 0 -a 0 -s 0x08000000 -D ~/utoc_firmware.bin