On 12/03/13 16:59, Bertho Grandpied wrote:
Some time ago, "Andrew Goodbody" noted :
I'm pretty sure that the detection of FWH devices requires
writing to the address space used and you cannot do that as
you cannot set the BIOS WE bit in the chipset. So unless you
can get around the SMI protection of that bit then there is
no way to detect the chip in use. Even if you did detect it,
you still could not program it.
And I responded :
I'll check whether the BIOS also has locked access to SMRAM
- usually it wasn't done at the time. If the SMRAM is
accessible from outside SMM, it would be straightforward to
bypass the protection (just replace an RSM instruction as
the SMI "handler" ;-)
Which was done successfully a mompent ago... BIOS was not locking the SMM
settings on this Intel board fortunately, so replacing a plain RSM instruction
at the SMI origin (A000:8000) took just a couple minutes' hacking, then for
sure Flashrom was able to detect the FWH, to dump and also to update the flash
image successfully :=)
Good work. Well done.
Andrew
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