[flashrom] Dump BIOS from an unsupported device

[Stefan Tauner]

On Tue, 13 Dec 2016 23:50:24 +0100
Antonio <sitadt11 at gmail.com> wrote:

> Hello everyone!
> 
> I would like to get a BIOS dump from my tablet for analysis purposes.
> 
> I read that laptops are not supported by Flashrom, so tablets should be even less so.
> 
> However I can't seem to understand if this limitation only applies to writing or reading as well.
> 
> Could anybody shed some light? Could I use the following without bricking my device? flashrom -p internal -r backup.bin
> 
> I'm ok if it crashes, just don't want to brick the tablet.
> 
> For further reference it's a BayTrail tablet with an Insyde UEFI BIOS

Hello Antonio,

basically it applies even to probing for the flash chip because in some
weird (but today almost instinct) configurations flashrom cannot talk
as direct to the flash chip as I would deem normal. In these cases
there is a bridge (EC) that converts the commands sent by flashrom via
LPC and conveys them over the native flash chip bus (SPI usually). This
conversion chip might react very weirdly to some commands it does not
understand that flashrom sends to interact with flash chips the EC does
not even know about. Because the EC is also responsible for power
management and similarly delicate stuff we do not recommend to run
flashrom on any laptop that is not guaranteed to NOT have this
configuration. However, as I said, these configurations are less common
today and even less on Intel platforms - so Bay Trail should be
completely safe to read out. However, you may not succeed anyway - i.e.
read might not work. But you can try and report back of course.

-- 
Kind regards/Mit freundlichen Grüßen, Stefan Tauner