Intel Firmware Descriptor

[Andy Pont]

Hello,

I’m working on porting Coreboot to a laptop that uses Intel Comet Lake.  
When the build completes it spits out the following warning:

** WARNING **
coreboot has been built without an Intel Firmware Descriptor.
Never write a complete coreboot.rom without an IFD to your
board's flash chip! You can use flashrom's IFD or layout
parameters to flash only to the BIOS region.

What is an IFD and how do I create one?

-Andy.

[Christian Walter]

Hi Andy,
If you already have a stock bios you can extract it with the ifdtool (ifdtool -x Image.bin). If you are doing a port for a hardware which happened to have no stock bios you need to generate the ifd and me with intels fitc tooling.
Best,
Chris

Von meinem iPhone gesendet
> Am 18.09.2020 um 16:09 schrieb Andy Pont :
>
> Hello,
>
> I’m working on porting Coreboot to a laptop that uses Intel Comet Lake.  When the build completes it spits out the following warning:
>    ** WARNING **
>
> coreboot has been built without an Intel Firmware Descriptor.
> Never write a complete coreboot.rom without an IFD to your
> board's flash chip! You can use flashrom's IFD or layout
> parameters to flash only to the BIOS region.
>
> What is an IFD and how do I create one?
>
> -Andy.
>
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[Michal Zygowski]

Hi Andy,

Intel Firmware Descriptor is a 4KB big binary structure that describes
the layout of the SPI flash in the Intel firmware. Besides the layout it
contains various straps for CPU and chipset configuration which is
sampled at power-on.

There is nothing to worry about the lack of IFD. You may still flash the
coreboot on your laptop, but you have to remember to leave the IFD
region (and ME region too) untouched. If you are using flashrom,
you should pass the "--ifd -i bios" options to the flashrom command when
flashing. It will instruct flashrom to overwrite the BIOS region only in
flash, where coreboot is supposed to be placed.

You may always extract the IFD for the original firmware of your laptop
and include it in your coreboot build. Creating own IFD is not recommended.

Best regards,