A patch fixing this issue has been merged into the main branch.

Thanks a lot for the bug report. I've now sent a patch to fix it. I'll also open new bugreports to contact other projects (Canoeboot and Libreboot) that use the same file even if they don't build images with GRUB as primary payload anymore.

I've done more research: I installed a Trisquel that is not encrypted and that has LVM2 and GNU Boot's GRUB didn't find the volumes.

So we could easily support cryptsetup in LVM2 but not LVM2 in cryptsetup or LVM2 alone.

To do that the best way would be to modify the ls command and somehow export the results to a variable (the probe command can do that for instance) and from that try to do a for loop on what was found.

My hypothesis is that it is a bug inside the GRUB configuration shipped by GNU Boot and that it has something to do with how you partitioned your hard disk and not the Gigabyte GA-G41M-ES2l as I can somehow reproduce that on a ThinkPad X200.

I've done the following to try to reproduce, I've used an X200 with 4GiB of RAM, and an hdd. I've used an image with a qwerty image, seabios and low resolution.

I've installed Trisquel 10, with the defaults and I end up with a GPT + MBR partition with:
/dev/sda1: 1M    BIOS Boot (GRUB is inside)
/dev/sda2: 513M  /boot/efi
/dev/sda3: ~20G  /home
/dev/sda4: ~900G /

Nothing is encrypted and the GRUB payload can boot this configuration.

I've also tried with a second hard disk has a very different configuration:

It has only an MBR and it looks like that:
/dev/sda1: LVM
           |-> Encrypted rootfs
               |-> rootfs
           |-> Many other LVM volumes (some encrypted some not)

Here GRUB cannot boot it despite being encrypted with LUKS1 and encryption algorithm compatible with GNU Boot.

When I try 'o' in the GRUB payload, I then end up on the same menu than you (the one in gnubootgrub.jpg).

I use Parabola on this HDD and I modified the Parabola /etc/default/grub and added 'GRUB_ENABLE_CRYPTODISK=y', 'GRUB_TERMINAL_INPUT=console', 'GRUB_TERMINAL_OUTPUT=console' and 'GRUB_PRELOAD_MODULES="part_gpt part_msdos lvm"' inside and it and then it can boot with SeaBIOS:

> SeaBIOS (version rel-1.14.0-28-g185d177c)
> Machine UUID xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxxx
>
> Press ESC for boot menu.
>
> Booting from Hard Disk...
> GRUB loading...
> Welcome to GRUB!
>
> Enter passphrase for lvm/[...] ([...]): []

Here SeaBIOS finds the Parabola GRUB and just runs it. But then I had to modify /etc/default/grub to make the graphics work and enable the Parabola GRUB to find the partitions.

So here the problem probably comes from the GRUB configuration we ship in GNU Boot.

I tried to use 'cryptomount -a' to open my rootfs in the GNU Boot GRUB, and then pressed 'ESC' to get back to the menu and selected 'o', and then it finds my Parabola GRUB configuration and it boots.

So my suposition is that by default it doesn't try to decrypt LVM partitions somehow.

comment #1:

> grub2 payload got this error message:
> +error: variable `prefix' isn't set.+
>
>

Test images:
seabios_grubfirst_ga-g41m-es2l_libgfxinit_txtmode_usqwerty.rom
seabios_withgrub_ga-g41m-es2l_libgfxinit_txtmode_usqwerty.rom
They work,but the grubfirst one can't not find the GNU/Linux that use lvm,i need to manually boot from grub2 command line.
It seems to grub2 payload don't work at this motherboard.(you can just only use the grub2 command line.)