Re: How to reinstall the bootloader without guix system reconfigure?

[Akib Azmain Turja <akib@disroot.org>]

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Felix Lechner <felix.lechner@lease-up.com> writes:

> Hi Akib,
>
> On Fri, Jul 1, 2022 at 4:35 AM Akib Azmain Turja <akib@disroot.org> wrote:
>>
>> Fortunately, I have Ubuntu (yet another nonfree
>> distribution) installed and it didn't broke, so used that to add that
>> 100 GB to my Guix partition.  But I found that GRUB is still broken.
>> Then I appended "/boot/grub/grub.cfg" of Guix to the same file of Ubuntu
>> and managed to boot into Guix
>
> Like Tobias, I cannot tell how Grub broke for you (although I do not
> dispute that it did).
>
> Grub needs to find a series of secondary files that, for EFI, are
> stored on the ESP. [1] For a traditional MBR/BIOS install, people use
> a small (1 MB or so) "BIOS Boot Partition" [2] although you probably
> aren't using that because your Windoze would not be able to use GPT
> without EFI. (Without GPT, Grub finds some place outside the partition
> table.)
>
> I think you are using EFI and an ESP.

How did you know?  I used to use Windows 10 even using a non-GPT (MBR
maybe?) disk.  And I still have that installed (though I don't use, not
even once in a month), just configured to boot with EFI.

>
> You may be encountering the issue that both Ubuntu and Guix are trying
> to manage the boot process. There is theoretically a way both Grub
> installations could coexist on the ESP but I am not sure they do. I
> personally would run Grub only in Ubuntu or Guix.

Both distrubtions have their own dedicate directory in ESP, so IMHO that
shouldn't be a problem.  And I have several OS installed simultaneously
for several years, without any problem.

>
> In your case. it may be hard to pick one over the other.
>
> Ubuntu scans your hard drive for other operating systems, including
> Winblows, but probably misses Guix. Guix on the other hand may
> miss the other two but knows the exact paths needed to boot into your
> most recent "Guix System" configuration.
>
>> Is there any way to reinstall bootloader without the costly "guix system
>> reconfigure"?
>
> To reinstall in Guix, you may be able to run 'grub-install /dev/sdX'
> but that does not stop the competition between Ubuntu and Guix. I may
> also make it harder for you to boot into Ubuntu or Winnows.
>
>> Another non-important question:  Why did Guix's GRUB broke while
>> Ubuntu's GRUB survived?
>
> I think they use the same folder on the ESP.

No.  Not at all.

>
> Maybe there is an expert who can chime in.
>
> Thanks for using Guix!

I would thank the Guix developer, who have developed such a wonderful
OS, which (almost) never breaks.

>
> Kind regards,
> Felix Lechner
>
> P.S. You can boot many systems manually from the Grub shell, but it
> would be an extraordinary burden to type the full Guix paths for your
> kernel and your initrd.
>
> [1] https://en.wikipedia.org/wiki/EFI_system_partition
> [2] https://en.wikipedia.org/wiki/BIOS_boot_partition

-- 
Akib Azmain Turja

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