[flashrom] SOIC8 test clip - cant write to BIOS SPI flash chip

[Nico Huber]

Hi Robert,

it might be easier to help if we knew your Laptop model. Also, please
provide a full log of the failing flashrom run with the -V switch, you
can specify a log file with -o.

On 17.10.2015 02:07, Robert Brown wrote:
> But here is a problem: I could read a dump from this BIOS chip without
> problems, however
Please further define "without problems". Did you try several reads and
compared the contents?

> it fails when I am trying to write - so the contents of BIOS flash chip
> are remaining unchanged.
Log please. By guessing two possible issues come in mind: 1. Your pro-
grammer doesn't provide enough power for erasure. 2. The write protec-
tion pin of your flash chip is asserted.

> Should I connect to motherboard a laptop's power battery, or small CMOS
> battery, or AC adapter of laptop,
I'd try with the AC adapter. In that case Vcc must _not_ be connected to
your programmer. GND, OTOH, has to stay connected.

> so that this Vcc pin would be powered by them, or it is forbidden to do
> it while using SPI programmer in the same time?
Not forbidden. It's sometimes even encouraged because there are boards
where the Vcc pin of the flash chip is directly connected to other
chips, which would draw down the power from the programmer.

> Or its better to try to power Vcc of flash chip from "USB to TTL"
> adapter - which has this 3V3 (3.3V) voltage pin?
It really depends on your machine.

Nico