[flashrom] Image size doesn't match the flash chip's size

[Stefan Tauner]

On Sun, 22 Nov 2015 18:57:16 +1000
Adam Nielsen <a.nielsen at shikadi.net> wrote:

>   Error: Image size (8192 B) doesn't match the flash chip's size
>     (262144 B)!
> 
> While I understand this would normally be a problem, for me it's fine -
> I'm only interested in the first 8kB and the rest of the chip is not
> important to me.  But I couldn't find any options to tell flashrom to
> continue and flash anyway, and --force didn't help.

Don't use the force switch. It's the dark force :P

> I guess I could pad out the 8kB XTIDE image to only 128kB, then
> double that to get a 256kB image, but it's all very kludgy!

But the right way, currently.

> would it be possible to add another option to allow partial flashing?

Yes, and we are working on that.
The current state of affairs can be found here:
https://github.com/XVilka/flashrom/tree/libflashrom_layout
One needs to write a layout file to use the additional functionality
but the base for it is already integrated, see below.

You are facing two problems actually:

1. flashrom expects a 256 kB file for a 256 kB flash chip. This does
   not completely change even with the patches above in their current
   form. So you still would need to prepare a file with 256 kB,
   although with the patches integrated it would no longer matter what
   is in there because you could specify additional files for any
   specific address ranges which need to be just as big as that range.
2. You want to write only a part of the chip. Either 128 kB because
   that's what the programmer is capable of, or even less because
   that's what your payload size is. flashrom supports this out of the
   box with layout files already. So you could prepare a 256 kB file
   with only the first 8 kB of valid data and use a layout file to tell
   flashrom to only write those 8 kB and stop then.

> 
> BTW flashrom (latest stable) tells me the SST29EE020 is untested, so I
> would be happy to report back with my results, assuming you accept
> flashing a 256kB chip in a 128kB programmer as a valid test ;-)

I think our policy regarding this is not to mark them as tested because
that access pattern could hide some real bugs even if that's unlikely.
After all, "untested" does not mean unsupported... all chips in the
code base should just work.

-- 
Kind regards/Mit freundlichen Grüßen, Stefan Tauner