[coreboot] Dualbios on GA-MA770-UD3

xdrudis xdrudis at tinet.cat
Sat Apr 24 19:43:24 CEST 2010

Thank you for your work on Dual BIOS.

What I don't understand is how is this supposed to work.

>From what you say and what I asked sales cotact staff at gigabyte (no
very useful insights) , there are two bios roms. One has the ability
to check the other and run it only if it detects it's ok. If it
doesn't it flashes itself to it.

So if you use one of the BIOS for coreboot it will either be rewriten 
by the original BIOS or it will boot, depending on which ROM boots 
first and which ROM you put coreboot in. 

If you flash the ROM that boots first you can try coreboot, but in case 
it doesn't work how are you going to jump to the original BIOS ? 

If you flash the other ROM then apparently the original BIOS will boot
and do what it pleases, possibly overwrite coreboot, or assuming you can trick
it to believe coreboot is a correct BIOS then maybe jump to it after 
some initialisation, but will coreboot then have a chance to work from the
same state it would in case it had booted first ? 

Tricking the original BIOS to believe coreboot is a correct image may be hard.
In the worst case you may have to break a digital signature without the private key.
This is not directly related, but gives an idea of how hard it could be

http://invisiblethingslab.com/resources/bh09usa/Attacking Intel BIOS.pdf

But assuming you can, will using coreboot after other firmware has set
up things far enough to be able to test the ROM where coreboot is in,
will that be a sufficient test ?  I'm not saying it won't, I have no

Anyway, being able to flash both chips is good at the very least in order
to have more space for payloads or so. 

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