The live usb is stuck on "Welcome to GRUB!"

[Paul Iannetta]

Hi Guix,
(If you answer please don't forget to add me in CC, since I am not registered 
yet)
tl;dr
I seem unable to make GRUB work and would like to know whether it is possible 
to generate an image which 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.
As 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 same 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.
The last solution would be to overwrite my current distribution by guix and 
replace the init system by sheperd.

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