Re: Boot Guix from Grub on Coreboot laptop

[Tobias Geerinckx-Rice]

Hi znavko,

TL;DR: see 'configfile' below.

On 2021-08-27 21:52, znavko--- via wrote:
> I burned an usb-stick that is booting perfectly on my PC, but it does
> not boot on the coreboot laptop. When I choose from the menu "Search
> ISO linux menu (USB)" it does not start booting from usb.

If that's a verbatim quote, that's one unclear menu entry!

I wonder if it's trying to refer to ISOLINUX[0], software we don't use 
at all.

Maybe it's just an awkward way of saying "search for .iso image files, 
on a file system, on a USB drive"...?  I'm just guessing here, but can't 
think of a reading that would be relevant to booting a correctly-created 
Guix installer and would disregard this option as irrelevant.

> And I enter grub command line and type:
> > ls
> ... (usb1) (usb1,msdos2)
> > set root=(usb1,msdos2)
> > chainloader /efi/boot/bootx64.efi
> error: unrecognized payload type.

You need a UEFI 'OS' like Tianocore to run .efi programmes.  Your other 
laptop boots one, your Coreboot one doesn't, by design.  That's OK: GRUB 
doesn't need UEFI, nor does Linux.

Don't try to chainload the GRUB on the USB drive at all.  Instead, 
simply let Coreboot's GRUB parse the Guix installer's configuration file 
directly like so:

  configfile (usb1,something)/boot/grub/grub.cfg

I can't say for sure what the exact drive + file name should be, but it 
will be very close.  Then Coreboot will display Guix's menu instead of 
its own, and you should be able to boot Guix with it.

Separately setting $root has never been necessary IME.

> I do not know what to do here.
> I also tried to find 'vmlinuz' and 'initrd' on '(usb1)' but it's hard
> to find them there.

(...who still uses 'vmlinuz'?  Anyway, Guix doesn't.)

Even then, this approach won't work.  The kernel and initrd file names 
alone aren't enough to boot the system.  See the Guix ISO's grub.cfg's 
'linux ...' line.

> Can you help? Could Guix OS boot under Coreboot?

Yes, but only if you call it by its name 'Guix System' from now on :o)

Here's a guide from someone who does so, although it seems to assume you 
use LUKS and Libreboot: 
<https://flossmanuals.net/pub/guix-system-and-libreboot.pdf>

Good luck!

T G-R

[0]: https://wiki.syslinux.org/wiki/index.php?title=ISOLINUX