[flashrom] reading the flash image of my Celsius H265

[David Hendricks]

On Wed, May 9, 2018 at 1:12 PM, Elmar Stellnberger <estellnb at elstel.org>
wrote:

> When I boot with iomem=relaxed and enable flash writing in my BIOS I get
> the following result with my Celsius H265 notebook:
>
> > flashrom -p internal:laptop=force_I_want_a_brick --read celsius2.rom
> flashrom p1.0-74-g2568357 on Linux 4.17.0-rc3+ (x86_64)
> flashrom is free software, get the source code at https://flashrom.org
>
> Using clock_gettime for delay loops (clk_id: 1, resolution: 1ns).
> ========================================================================
> WARNING! You seem to be running flashrom on an unsupported laptop.
> Laptops, notebooks and netbooks are difficult to support and we
> recommend to use the vendor flashing utility. The embedded controller
> (EC) in these machines often interacts badly with flashing.
> See the manpage and https://flashrom.org/Laptops for details.
>
> If flash is shared with the EC, erase is guaranteed to brick your laptop
> and write may brick your laptop.
> Read and probe may irritate your EC and cause fan failure, backlight
> failure and sudden poweroff.
> You have been warned.
> ========================================================================
> Proceeding anyway because user forced us to.
> Found chipset "Intel ICH9M-E".
> Enabling flash write... OK.
> Found Winbond flash chip "W25X32" (4096 kB, SPI) mapped at physical
> address 0x00000000ffc00000.
> Reading flash... done.
>
> However if I execute this twice I get two different images:
> wget https://www.elstel.org/uploads/celsius.rom
> wget https://www.elstel.org/uploads/celsius2.rom
>
> Using vbindiff I can see that quite a lot is different between both
> images. - which would be difficult to achieve if the firmware was changed
> while I am running my computer. The image may be somehow corrupted as
> me_cleaner (BIOS offers Intel AMT) can not process the image:
>
> python ../me_cleaner/me_cleaner.py -S -O celsius-no-me.rom celsius.rom
> Unknown image
>
> See also the dmidecode that I have attached.
> How can it be that both images are different?
> Do you think that the images are corrupted?
> If so what could we do about it?
>

There is probably an embedded controller (EC) connected to the SPI ROM that
is accessing the ROM at the same time as flashrom. See
https://flashrom.org/Laptops for details.

If this is the case, then you will need to figure out how to prevent the EC
from reading/writing the ROM at the same time as flashrom. This could be as
simple as disabling your OS's power management daemon to avoid stimulating
it, or it may require sending a command to the EC (likely a sequence of
OUTBs) to put it into an update or recovery mode to prevent it from
accessing the firmware ROM.
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