Dear Florian (and André),

I found the cause. It was my fault I created a second EFI partition for
the guix grub (to be sure it doesn't make my Debian installation
unbootable) and mounted the EFI partition on /mnt/boot (instead of
/mnt/boot/efi) This way the EFI directory was not top level an more
important the bootcode that was made known to the efi was at the wrong
location.

Now the guix system is woking fine.

Of course now the next issues arise, like "how do I configure postfix
under guix" and what is the right way to make my keyboard layout known
to the system (so far I have added a few lines (a variant) to the
/usr/share/X11/xkb/symbols/us file, wich is now hidden somewhere in the
guix-store)? Guix configuration is really very different from other
*ix'es. Are packages configurable at all without writing scheme-modules
for them? An where would this configuration go? Is everything hidden in
some directories in the gnu store? 

Cheers,
Alex

On Do, Nov 11 2021, 21:58:40, pelzflorian (Florian Pelz) wrote:

> Hello Alexander.
>
> On Thu, Nov 11, 2021 at 06:48:37PM +0100, Alexander Asteroth wrote:
>> Ok, you all convinced me to give Guix a third try (yes I already gave up
>> twice).
>
> The name of the operating system distribution that can be installed
> with the Guix package manager is Guix System.
>
>
>> Today I installed guix on a seperate partition aside the
>> Debian-11 install on the same HD. Everything went fine but for the
>> bootloader.
>
> This sounds like a bug.  Does your computer boot with EFI?
>
> When installing, do you configure a mount point such as /boot/efi for
> your existing boot/EFI system partition?
>
>
>> I thought maybe it's best to not install it and let
>> os-prober on the Debian side discover the Guix system (which I mounted
>> on /mnt). Unfortunately it seems not to recognize the Guix-Install
>> (maybe because the kernel-image is hidden deep in the store?).
>
> Yes, that is probably the reason.
>
>
>> Vice
>> versa I could add the Debian partition to the Guix config but if
>> something goes wrong ... ?
>
> However, if you boot from EFI, you maybe can use the EFI boot menu to
> switch between Debian’s and Guix’s bootloader if both are installed.
> This should be sufficient to dual boot.  For extras:
>
> If both are installed, it is even possible to configure Debian’s grub
> bootloader to chainload Guix, although I no longer know the commands
> for chainloading.
>
> For the opposite, to boot Debian from Guix’ GRUB EFI bootloader, do
> this: After installing Guix to boot Guix, I used to change my
> /etc/config.scm like this:
>
>  (bootloader (bootloader-configuration
>               (bootloader grub-efi-bootloader)
>               (targets '("/boot/efi"))
>               (keyboard-layout keyboard-layout)
>               (menu-entries
>                (list (menu-entry
>                       (label "Debian")
>                       (linux "(hd1,gpt4)/boot/vmlinuz-4.19.0-6-amd64")
>                       (linux-arguments '("\
> root=UUID=387b3930-178a-4f35-b89c-e77a2c25e686"))
>                       (initrd "(hd1,gpt4)/boot/initrd.img-4.19.0-6-amd64"))))))
>
> The initrd and root settings I took from Debian’s GRUB bootloader
> configuration.
>
> Regards,
> Florian