[coreboot] [PATCH] flashrom: ST M25P40 bug?

Uwe Hermann uwe at hermann-uwe.de
Sat Mar 29 17:28:32 CET 2008

On Sat, Mar 29, 2008 at 04:42:24AM +0100, Fredrik Tolf wrote:
> I don't know if this is a bug, or if there are somehow two completely
> different versions of the ST M25P40 SPI chip.
> I just tried to burn such a chip with flashrom, but it wouldn't detect
> it at all, so I checked the datasheet for it, and it turned out that the
> probe was completely different from what one would think, reading
> flashrom's source.
> It seems that the M25P40 doesn't use the RDID command to send its ID,
> but rather a "RES" (Read Electronic Signature) command instead, which
> returns just one byte. I added support for it, and then it worked
> perfectly for me.
> I'm attaching my patch to fix the problem. I would imagine that the
> other M25Pxx chips would be affected by the same problem, but since I
> can neither verify nor test what IDs they would have, they are excluded
> from my patch.

I don't know too much about SPI, I'll let Carl-Daniel review this patch ;)
But please resend with a Signed-off-by line, otherwise we cannot commit
the patch, see


Thanks, Uwe.
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