Re: Devuan replaced grub and runs before Guix

[raingloom]

On Mon, 27 Dec 2021 00:32:18 +0100
Youni Git <git@youni.world> wrote:

> Hello, dear developers! Merry Christmas and Happy New year!I would
> like to ask questions I did not dug in the web, I hope there are
> short answers.I had Guix OS installed on /dev/sda and i had grub
> bootloader there configured to run guix and devuan from another sdd,
> my
> config:https://gitgud.io/youni/guix-configs/-/blob/master/config-wpa2-wlp5-wf-blacklist--my-desktop-services--isp.conf#L91Everything
> worked fine, i could boot to Guix or choose Devuan from the grub menu
> controlled by Guix.But i made Devuan 3 to Devuan 4 upgrades. And
> Devuan replaced grub and now i have no guix in the menu.I think i can
> add Guix to devuan grub menu, but I'm not sure I can find /vmlinuz
> and /initrd files in the Guix partitions.I have 3 questions:1. How to
> boot Guix manually from grub command line?2. How can I add Guix OS to
> devuan grub menu, which files i need to use for linux image and
> initrd, where to find them on Guix?3. Can I easy replace back grub by
> Guix making guix controls grub again?Thank you.

Oh heck, I used to manually kexec Guix, but it was on a different drive
with its own GRUB install.
/run/current-system seems to point to store entries ending in -system.
So to find the store item:
find /gnu/store -maxdepth 1 -name '*-system'
Within the store item:
kernel/bzImage: this is the kernel image to boot.
initrd: this is the initramfs

That should be enough info to build a GRUB menu entry. There are
some other options like modprobe.blacklist but I'm not sure where
they are in the store.

Oh there is also the init binary. Uh. Not sure where that is.

But I think this is a good enough starting point, hopefully you can
figure out the rest.

Alternatively, maybe try chrooting into the Guix partition and running
reconfigure again?

In any case, good luck!