Hi @Cipher, have you already tried modifying the BIOS/UEFI of your G20CB using CoffeeTime? reactive proposed this before me (you can find the post here).
As far as I know, the attempts to run a CoffeeLake CPU on a G20CB so far were based on using some part from another platform’s BIOS/UEFI on the G20CB, which resulted in a few limitations (the mainboard HDMI didn’t work, for instance). As far as i know this method was used because at that time tools like CoffeeTime were not yet fully developed and the CoffeeLake mod was therefore a bit more experimental.