[coreboot] ultimate VGABIOS extraction! +NEW working way for AMD laptop's discrete GPU

[Nico Huber]

Hi,

On 07.07.2017 20:03, Mike Banon wrote:
> === ROM locations examples for 0x0 - 0x42F000000 dump made while 16GB RAM:
> 
> 0x000512000 - broken integrated graphics ROM, first "ghost"
> 0x3250D9020 - broken integrated graphics ROM, second "ghost"
> 0x3578FB000 - broken integrated graphics ROM, third "ghost"
> 0x36B22A01C - broken integrated graphics ROM, fourth "ghost"
> 0x4122BD000 - broken integrated graphics ROM, fifth "ghost"
> 
> 0x42D3B3000 - working integrated graphics ROM !!!
> 
> 0x42D305020 - working discrete graphics ROM (first working copy, the same)
> 0x42E40DCD0 - working discrete graphics ROM (second working copy, the same)

nice work! If these are physical addresses, dumping from Linux should
come easy: Boot with `iomem=relaxed` in the kernel command line and then
as root execute:

    # dd bs=1 skip=$addr count=64K if=/dev/mem of=dumped.rom

where $addr is the physical address.

Would be interesting to know, if these lie within a reserved BIOS area
of the RAM. If you can confirm that they are physical addresses, please
append the output of `dmesg`.

Nico