This is gamepad firmware that runs on the CH552T chip. It works with Flatbox rev6.
It is a minor modification of Stefan Wagner's CH552-MouseWiggler.
To compile the firmware you need the sdcc compiler. To flash the firmware you need the pyusb Python module.
To build the firmware, run make bin.
To build and flash the firmware onto a board, hold the "BOOT" button while plugging the board into your computer, then run make flash immediately after.
To flash an existing binary, hold the "BOOT" button while plugging the board into your computer, then run python3 tools/chprog.py gamepad.bin immediately after.