"flashrom" command succeeded on reading chip containing one-time programmable memory on 3 trials, but "cmp" command says there are different bytes among the 3 output files.

[Alan K.L. Mok]

Hello Flashrom team,

As captioned. I read the flashrom man page and understand that one-time
programmable memory may be out of scope of flashrom and hence the failure
on my chip readings.

My goal is to make a backup of the chip before I put my motherboard into
production and connect it to the internet. If my motherboard is hacked and
content within the chip changed, I can easily roll back the chip to a known
trustable state by flashing the backed up image back into the chip.

Can you please advise how I can achieve my goal? Should I go purchase a
hardware flash programmer and mess with it (I don't have any electronic
knowledge)? I searched the net and found "Bus Pirate", am I correct to say
that it is a programmer/debugger that can talk "directly" to the chip?
Would this possibly help in my case?

Motherboard                  : ASRock X300M-STX
CPU                          : AMD Ryzen 5600G
BIOS chip                    : Winbond W25Q128.w
"AMD fTPM switch" within BIOS: Disabled
Programmer used              : CH341a /w USB interface

Thank you for your time considering my questions. I hope you will have a
good day.
Alan

[awokd]

Alan K.L. Mok:
> Can you please advise how I can achieve my goal? Should I go purchase a
> hardware flash programmer and mess with it (I don't have any electronic
> knowledge)? I searched the net and found "Bus Pirate", am I correct to say
> that it is a programmer/debugger that can talk "directly" to the chip?
> Would this possibly help in my case?
>
> Motherboard                  : ASRock X300M-STX
> CPU                          : AMD Ryzen 5600G
> BIOS chip                    : Winbond W25Q128.w
> "AMD fTPM switch" within BIOS: Disabled
> Programmer used              : CH341a /w USB interface

Have you tried using AMD's internal flasher to read the chip? What is 
the full command you used to run flashrom, and what was the error?

I'm a bit confused because you are looking at Bus Pirates, but list a 
CH341a w/ USB as the programmer used, which is also a fine external 
programmer. Does that mobo have one onboard?