*oven ding* it's done 
Took me a while to finish this because of life-related reasons, but finally sat down and fixed (most) remaining issues during the weekend. Pretty much everything* is working - including S3 suspend/resume, automatic fan control and so on (plus it draws less power than stock, I have no idea what AMI is doing).
Feels kinda surreal to have a fully-functional computer 
If you have an "MSI PRO B760-P WIFI DDR4" motherboard (or "MSI B760 GAMING PLUS WIFI DDR4", pretty sure they're the same just with different UISetup skin) you can now flash #coreboot on it.
DDR5 versions can be easily added if someone is willing to work/test it, just a matter of telling FSP you're using a different memory type.
Will document stuff (like making flashing cable that won't void warranty) later. Enjoy 
review.coreboot.org/c/coreboot…
