The unit I found was not so nice at the beginning, I just cleaned it up and the result was good enough.
For the gamepads I have used db9_gpio_rpi driver (https://github.com/petrockblog/RetroPie … 9_gpio_rpi).
You need to use modprobe to load it. For the use of 2 original (3+1) buttons pad, you have to use “modprobe -first-time db9_gpio_rpi map=4,4”.
For the Reset button I have used Pikeyd which emulates a “KEY_ESC” press on the GPIO.
Yeah I sold it for $150. Less than I would have liked but I bought 6 broken Genesis units so that sale covered the Raspberry Pi, all the broken Genesis units, and my time so if I make more to sell then I will score a profit.