Can't boot linuxloops Arch.img from external SSD GRUB - ZSTD decompression fails

[ImFiru]

Hey sebanc,

I'm trying to boot a linuxloops Arch.img (100GB, BTRFS) from an external SSD. GRUB is installed on the SSD's EFI partition, exFAT data partition has /imgs/Arch.img.

with this menu entry:
menuentry 'Arch1-test' --class 'arch' {
insmod exfat
rmmod tpm
set root=(hd0,gpt2)
set img_path="/imgs/Arch.img"
search --no-floppy --set=root --file "${img_path}"
loopback loop "${img_path}"
linuxloops_args="rdinit=/linuxloops img_path=${img_path} img_uuid=${img_uuid}"
export linuxloops_args
configfile (loop,2)/@boot/grub/grub.cfg
}

I get:

EFI stub: WARNING: Decompression failed: ZSTD-compressed data is corrupt
EFI stub: ERROR: Failed to decompress kernel
error: image not loaded.

Tried insmod zstd gcry_sha256 etc, --force flag, even reaches initramfs sometimes but hangs on /dev/mapper/loop2p2.

Is there something special needed for GRUB on external SSD + linuxloops?

[sebanc]

Hi,

Indeed there are 2 separate issues:

• zstd module is not included by default in certain grub versions, I have to think about this but for now a workaround is indeed to add "insmod zstd" in the linuxloops generated configuration or to use another grub version with zstd support included.
• The "reaches initramfs sometimes but hangs on /dev/mapper/loop2p2" part is due to the rootfs not being available early enough and it should now be fixed.

[ImFiru]

when you say it should be fixed now what do you mean by that ? added the insmod zstd part and now it boots to the emergency shell of archlinux.

Can't manage to make it work.

[sebanc]

Sorry I missed your comment, I meant that if you recreate the image it should boot instead of going to the emergency shell but you will probably still need to manually add "insmod zstd" in the grub configuration