Thanks a lot for the information. physrd is also a very nice and useful utility, it works on my board..
2011/10/21 Peter Stuge <[email protected]> > Alp Eren Köse wrote: > > > > But unfortunately I needed a windoz machine to extract the CMC > binary, > > > > you can use the CBROM utility like this: > > > > C:\> CBROM32_195.EXE vendor_bios.bin /TOPHOLE:FFFD0000 extract > > > I'd say you can do the same with dd(1), no? > > > > > Oh yes of course, that's very likely probably :) that should be something > > like this maybe: > > dd skip=(blocks until FFFD0000) if=vendor_bios.bin of=cmc.bin > > is that right? I'm not good at those block calculations:) > > The theory is in the right direction but the details are wrong, and > the command can't work at all. > > () creates a subshell in most if not all shells; not what you want. > > To give dd the correct parameters you need to know where cmc.bin > starts. FFFD0000 is not the answer; it is the correct physical > address when the factory BIOS image is in a flash chip that the CPU > can address, but it is obviously not the correct offset in the file. > > You know that the factory BIOS image is mapped to top of 4GB physical > address, so you need to use subtraction to find the correct offset: > > offset = 0xfffd0000 - (0x100000000 - size of factory BIOS image) > > Then you need to express the offset in a way that dd understands. As > you know from the dd man page, dd uses blocks, and you can set any > block size you want. Since a factory BIOS image size will always be a > multiple of 64KB, and this is how much you want to copy, and since > all other terms in the above equation are 64KB aligned, and since it > is such a nice round number in binary and hexadecimal, 64KB seems > like a good block size. Translate the offset into number of blocks: > > offset_in_blocks = offset / 65536 > > And run dd: > > dd if=factor_bios.bin of=cmc.bin bs=64k skip=offset_in_blocks count=1 > > > Another method is to use http://stuge.se/physrd.c to try to read from > the flash chip directly, then you do not need to do maths, but on the > other hand you must compile a special program and if you are unlucky > the address region is not accessible by the CPU without special magic > that flashom knows. You would run: > > ./physrd 0xfffd0000 64k cmc.bin > > > I think the calculation is faster and simpler. > > > //Peter > > -- > coreboot mailing list: [email protected] > http://www.coreboot.org/mailman/listinfo/coreboot >
-- coreboot mailing list: [email protected] http://www.coreboot.org/mailman/listinfo/coreboot
