You can buy pre-flashed and pre-modded Goteks from me...
Flashing the Gotek using USB
Materials required:
You just need a way to jump 2 pins (any piece of wire will do), and a USB-A to USB-A cable.
I did videos on this procedure. Determine if your Gotek is ST based or ARTERY Based, then use the appropriate software to flash the Gotek via USB.
Click the appropriate YouTube video link on ARTERY or ST Goteks below
ARTERY Gotek Flashing and Mods
NOTE: If you have a Gotek and the 2 R.E. pins are missing, use this connection instead for the rotary encoder.