I Had this same problem yesterday. (Q-Code Error F.F. - CPU Red LED problem)
My Config:
Asus RoG Crosshair V Formula-Z AM3+ (lastest BIOS)
AMD FX6100 3.3 @ 4.1Ghz
2x4GB DD3 1600Mhz G1 Skill - RipjawsX (9-9-9-24)
2 SATAII HDD Samsung Spinpoint F3
1 SATAII CD/DVD RW LG.
Sapphire RadeonHD 6870 1GB
PSU OCZ ModXtream 500W 80 plus Bronze.
With that config, my PC was working fine! no crashes, no BSOD, nothing wrong. for a few Months!
O got this problem when i decided to CrossfireX with 2 Sapphire 6870 (Twins).
First of all, i tested the new Sapphire in single mode. Running Battlefield 3 OK for 20 min.
So, with all hardware working fine. a decided to assembly my CrossfireX.
The only thing I thought that could go wrong, it would be the PSU couldn't handle it. But that would only shut down. That did not happen. The PC powered UP!
I got back to my initial config, same problem (one GPU).
i tested a new PSU, same problem.
I've Remove the Bios Battery, nothing.
I've remove one Dram Module, testing one by one, nothing
I've tested my Processor in another Board, Working Fine!
I've remove those 2 Dram modules, (expecting that code changed), same FF code.
I've removed BIOS and put it again, nothing.
I updated the BIOS using the ROG connect port, Successfuly, but still nothing.
Doing a web search, I found some people with this same problem. The interesting thing is what happened with motherboards from various manufacturers, for both AMD and Intel.
It is obvious by the fact that all manufacturers have such Code FF, it's probably a bug (kernel panic) in the BIOS (UEFI) by the fact tha even the board doesn't know what is it. corrupting the Motherboard Startup.
Solution? RMA to Manufacture to get a New One!