Re: [flashrom] Intel C602 support

[Stefan Tauner]

On Mon, 6 Aug 2012 12:07:47 -0700
Greg Schardt  wrote:
> Can you explain why doing a read operation failed? I expected that reads would work and writes would fail.

each region can have 4 different access states: read/write, read-only,
write-only (never seen in practice), locked (neither read nor write
allowed) (see FREG in the public datasheets for any newer intel
southbridge >ICH8).
flashrom disables writes by default if it detects locked or read-only
regions as a safety measurement and still allows reads because they can
not lead to the same severe damage. in case of locked regions reads of
addresses inside those regions will of course fail.

there are some patches available that are not merged yet that allow to
specify the addresses to be read/written, which allow to read/write the
readable/writable address ranges.

Intel C602 support

[Greg Schardt]

Stefan,

I have modified the flashrom code to allow reads and writes to unprotected regions to occur, but am still blocked by having the ME region locked. Do you have any idea how the AFUDOS utility is able to modify the Management Engine region even though it should be locked? I would have thought that the Region Access Control settings would be in effect once the BIOS finished booting, before DOS could start. According to documentation, asserting HDA_SDO is the only way to override these settings, do you think that is the mechanism being used?

Thanks,
Greg

-----Original Message-----
From: Stefan Tauner [mailto:[e-mail]] 
Sent: Tuesday, August 07, 2012 3:39 PM
To: Greg Schardt
Cc: [e-mail]
Subject: Re: [flashrom] Intel C602 support

On Mon, 6 Aug 2012 12:07:47 -0700
Greg Schardt  wrote:
> Can you explain why doing a read operation failed? I expected that reads would work and writes would fail.

each region can have 4 different access states: read/write, read-only, write-only (never seen in practice), locked (neither read nor write
allowed) (see FREG in the public datasheets for any newer intel southbridge >ICH8).
flashrom disables writes by default if it detects locked or read-only regions as a safety measurement and still allows reads because they can not lead to the same severe damage. in case of locked regions reads of addresses inside those regions will of course fail.

there are some patches available that are not merged yet that allow to specify the addresses to be read/written, which allow to read/write the readable/writable address ranges.