OpenBuilds BlackBox includes a jumper that can be removed to disable USB Autoreset (Arduino / DTR style reset circuit).

For normal use cases, the jumper can be in either position, but for Firmware Updates it should be in the CLOSED position.

If your BlackBox shipped with the jumper removed (some versions do), be sure to remove it again after firmware update to prevent damage. If you do not have a spare jumper, you can borrow one of the others jumpers.