I haven't got much further than when I posted on this mailing list.
I still haven't found the exact cause to why the SATA ports dies when booting linux.
However my main computer has died so I don't have any computer that I can use when I'm trying to get coreboot running on that mobo.
But because that computer died I could use the GPU that survived to see if the pcie ports were working with my coreboot image. That wasn't the case so I suspect that the sata and pcie problems are because of the rs780 (northbridge) is not working correctly.
I suspect that this is because I mix AGESA with code that were used before AGESA was in coreboot. Because no other board does this I suspected from the start that it would turn out ugly in the end. But it was worth a try :)
I took a look on the northbridges that have been ported from pre-AGESA to AGESA boards. But it seems to me that I will not be able to port it myself as alot of the code seems to heavily rely on vendorcode that AMD as supplied to coreboot. (There is no vendorcode for rs780, I think)
Because I think that I lack the necessary knowledge to port it over myself, and because I can't afford to buy a new computer to use for coreboot porting, I won't get much further.
The code is still hosted on my github page: https://github.com/DarkDefender/coreboot
What works is: CPU/RAM (tested with bulldozer and 16GB ram) Booting to Seabios/grub2 Booting from HDD/Usb with seabios/grub2 Runnig linux from usb with serial output
What might work: PS2 keyboard (Didn't test it out as I had to do everything over serial but turning numlock on/off works as the LEDs responds to those key presses. And kernel panics trigger the LEDs to flash on it also.)
Onboard LAN (The kernel seems to init it fine, but I didn't try to connect it to a network)
What doesn't work: SATA ports when booting linux (Haven't tried any other OS) Onboard audio Onboard GPU Pcie ports (And I'm guessing the pci ports also)
I don't know if I should try to push this code into coreboot or not. It's pretty non functional as I don't think anyone would be happy with running with only serial and having to use USB as the only main storage source.
Anyways, It's been a fun ride. I would like to thank everybody that helped me in some way. I wouldn't gotten this far without you guys! :)