AI isnt going to beat you for creative, functional answers, but for being
a whole lot more polite.
https://github.com/PancakeBot/PancakeBot-firmware/
I know it says Linux unsupported, but I don't own a MsOS box to do the firmware update.
No Mater! it is still doable, here is how:
Generically:
$ avrdude -v -p m2560 -c stk500v2 -P /path/to/device -b 115200 -D -U flash:w:/path/to/PBFirmwareUpdate2.0.hex:i
$ avrdude -v -p m2560 -c stk500v2 -P /dev/ttyUSB0 -b 115200 -D -U flash:w:/home/user/Desktop/pbfw/PBFirmwareUpdate2.0.hex:i