Hi-
So would the  solution be to flash the larger chip with some external tool like a Raspberry Pi and adjust the size of the CBFS in coreboot (can do both, shouldn't be a problem). 

I guess I'll need some other payload with a SPI driver to access the remaining space (u-boot? No luck there so far..) right?

Thanks,
Rafael

On Mon, Aug 26, 2019 at 11:43 AM Nico Huber <nico.h@gmx.de> wrote:
Hi Rafael,

On 26.08.19 20:30, Rafael Send wrote:
> When I replace it with a larger chip (32MB in this case), the detected chip
> is still the same as before (Opaque flash chip, size 8MB) but the new chip
> is a MX25L256.

the flash chip size is encoded in the Intel Firmware Descriptor (first
4KiB of the image). I don't think there is an open-source tool to update
it, but if you dig into flashrom sources (ich_descriptor.[ch]), you
should be able to figure out which bits to change. To make use of the
additional space, you'll also have to update the partitioning (ifdtool
of coreboot can do that, iirc).

Alas, since Skylake, Intel doesn't allow to access the SPI bus directly
anymore. So there is only the "opaque flash chip" and flashrom can't do
its job with a wrong descriptor.

Nico