LiveUSB stuck at GRUB welcome screen

[Iannetta Paul]

Hi Guix,

tl;dr

I seem unable to make GRUB work and would like to know whether it is 
possible to generate an image that would use extlinux/syslinux instead.

---

I am trying to install guix on a pretty old box (an HP Pavilion dv6000 
series from circa 2010) with no efi support. I've been running funtoo on 
it for the last 5 years or so and everything is okay, the bootloader is 
GRUB.

At first, I tried to surgically snipe (by overwriting) the `grub.cfg` on 
the iso (directly with dd and the offset of grub.cfg on the iso) to not 
use gfxmode, to no avail. The file was properly overwritten but it 
seemed to not be sufficient.

Secondly, I installed the package manager guix on funtoo and tried to 
create an image myself.  That proved more tricky than I expected because 
since guix is running on a foreign distro there is no initial system 
configuration... and doing `guix system image -t iso9660 install.scm` 
fails by telling you that there is no file `install.scm` even though the 
file is in the current directory.

From that point, I looked up (with `locate`) the location of 
`install.scm` files on my system, and there was a couple in 
/gnu/store/xxx-guix/.../gnu/system/, I used the one which looks like 
this ( https://github.com/lfam/guix/blob/master/gnu/system/install.scm 
). After some fiddling (some deprecated syntax (targets instead of 
target) and missing fields (missing description here [1]), the part with 
the loopback required an `addresses` field, etc.) It worked to create an 
image, but it was still grub.

I tried replacing `grub-bootloader` on line 455 by `extlinux-bootloader` 
and added `#:use-module (gnu bootloader extlinux)` at the top of the 
file. I could generate an image from that file but as before the 
bootloader was still grub.

At that point, I tried the various options of grub to modify the gfx 
resolution (I suspect that grub fails to find the correct resolution of 
my screen and stops at the welcome screen), it worked and was reflected 
in the `grub.cfg` of the image. Nevertheless, the boot did not proceed 
any further :(

I would really like to try building an image with syslinux/extlinux to 
see whether I can go further but I am currently stuck now. I've read 
this page [2] but it is still unclear. The generation with the 
`pine64.scm` file works fine but not with my custom file (guix system 
complains it does not exist, and the most surprising is that if I copy 
past the content of my custom file into the `pine64.scm`, the 
`pine64.scm` file is reported missing...)

The last solution would be to overwrite my current distribution by guix 
and replace the init system by shepherd.

[1]: 
https://github.com/lfam/guix/blob/master/gnu/system/install.scm#L251

[2]: 
https://guix.gnu.org/cookbook/en/guix-cookbook.html#Guix-System-Image-API

Regards,
Paul

--
Iannetta Paul
ENS de Lyon