[coreboot] C720 swapparoo

John Lewis jlewis at johnlewis.ie
Thu Jan 30 00:57:20 CET 2014

On 29/01/14 22:03, Aaron Durbin wrote:

> The issue w.r.t. cbfstool complaining is that in the header of the
> cbfs there is a field which states 8MiB rom. So you need to make an
> 8MiB file with that upper 1MiB cbfs at the top. It should then read
> properly.
> In other words: rom size != cbfs size.

I now know what you meant by the above - the CBFS header contains a 
value which defines the size of the file it comes as part of. The file 
size was wrong versus this value, so cbfstool couldn't read it properly.

I guess, therefore, that in the older generation of Chromebooks the 
header value was just 1 MB, hence why it had to be extracted with 
fmap_decode and dd. The new rom "format" negates the need to do that, 
which is nice. :)

Thanks again,


More information about the coreboot mailing list