Sorry, at the moment I could only suggest to "find" a Windows 7 USB, do a clean install & drivers installation and use this Belkasoft tool according to ultimate VGABIOS extraction writeup - that's if you need it quick. However, if you'll achieve a similar access with Lime, please let us know: it is much better if stuff like this could be done with the opensource software and no Windows hassle.
On Fri, Apr 16, 2021 at 10:52 PM Peter Stuge <pe...@stuge.se> wrote: > > Gian Lorenzo Spisso wrote: > > Thank you so much for your reply. > > > > Indeed, after a bit of research I've stumbled upon Lime which is a kernel > > module allowing the dump of the whole memory which I'm doing right now. > > Oh good, that's worth a try. > > > > Do you have any pointer on how to locate the bit I'm interested in? > > Here's a hex dump of the first 80 bytes of my VGA BIOS: > > 0000000: 55aa 80e9 a9e3 3030 3030 3030 3030 3030 U.....0000000000 > 0000010: 3030 b021 e9a1 2059 4000 e00a 3030 4942 00.!.. Y@...00IB > 0000020: 4d20 5647 4120 436f 6d70 6174 6962 6c65 M VGA Compatible > 0000030: 2042 494f 532e 2003 5b00 6b00 7900 8bc0 BIOS. .[.k.y... > 0000040: 5043 4952 8680 a227 0000 1800 0000 0003 PCIR...'........ > > Bytes 0 and 1, 0x55 and 0xaa, mark the start of the option ROM, > and offsets 0x44-48 (0x86 0x80 0xa2 0x27) contain the PCI ID of the > graphics hardware that this option ROM is for. > > The PCI ID of my graphics hardware is 8086:27a2; note that the two > 16-bit numbers are stored little-endian in the image. > > Searching for this in e.g. a large file again needs some programming, > because the individual bytes (0x55, 0xaa, or the ID bytes) will occur > quite frequently. > > One option might be to first look for some text strings in the > internal VGA option ROM and see if they occur in more locations in > the new memory dump, to then search only those regions manually. > > > > I am alsok wondering, should I make sure my gpu is running since > > its a discrete card for the vbios to be loaded in memory? > > Hm, I think that will depend on the particular hardware design of > your GPU and of your mainboard. The GPU should not be powered down, > because the option ROM is probably only accessible through the GPU. > > > Finally, if the software approach fails, another method may be to look > for the flash chip on the mainboard and read it out with hardware means. > > > Kind regards > > //Peter -- Best regards, Mike Banon Open Source Community Manager of 3mdeb - https://3mdeb.com/ _______________________________________________ coreboot mailing list -- coreboot@coreboot.org To unsubscribe send an email to coreboot-le...@coreboot.org
