[flashrom] Gigabyte GA-J1900N-D3V-1.x data

[Stefan Tauner]

On Sat, 20 Dec 2014 14:03:43 -0800
Matt Taggart <matt at lackof.org> wrote:

> Stefan Tauner writes:
> 
> > thanks for you report. The flash chip is marked as untested... have you
> > verified visually that the actual chip on the board is either a
> > MX25U6435E or MX25U6435F,
> 
> Yes, they (2, since it's 'Dual BIOS') are marked
> 
>   MXIC MX
>   25U6435F
>   M2I-10G
>   8A615600
>    L140295
> 
> More notes about the board at
> 
>   http://lackof.org/taggart/hacking/coreboot/GA-J1900N-D3V-1.x/README
> 
> > and if the read data seems legit?
> 
> How would I test for that? The checksum of the image read does not match 
> the blob in the vendor update package of the same version (but I suspect 
> 'Dual BIOS' has something to do with that). 

That's not unusual for various reasons (e.g. the firmware uses the
flash as scratchpad). The rom.bin on your website looks sane to me and
since I don't expect any problems regarding reading the chip with
flashrom, I will mark probing and reading as tested, thanks.

> Can I binary diff them somehow 
> or would something like compression interfere with that? Are there tools 
> for picking apart the image to make comparison easier?

There is ich_descriptor_tool (in flashrom's util directory), there is
ifd_tool in coreboot's repository, and there is bios_extract and
various related tools.
 
> Also I'm a little concerned about something I read somewhere about 
> Gigabyte's "Dual Bios" feature and possibly needing to give flashrom 
> additional info in order to deal with that (but I can't find where I read 
> it now).

Flashrom supports accessing both chips. For the second one there is a
command line option, see the man page.

> How should I process with testing? I haven't setup a way to external flash 
> yet, maybe the first step getting a good external read that I'd be able to 
> write back if things went wrong?

Getting a way to recover is certainly a good idea ;) I'd expect the
image you have read already to be fine, but without an external
programmer it does not help much.

I am not up to date how coreboot handles dualbios. In earlier days it
was a problem because the backup bios always kicked in to replace
coreboot without a hardware hack. That might be different now and
something the coreboot guys could probably answer.

From flashrom's perspective there is no need to test anything
specifically at this point on that board... if you happen to test
writing the chip/on this board I'd be happy to know about though.
Everything else should be addresses to the coreboot mailing list.

-- 
Kind regards/Mit freundlichen Grüßen, Stefan Tauner