Load ISOs from GRUB directly

[filo]

There is something similar which has been suggested or mentioned here in the forum several times.
I learned it from @SGS and liked it a lot , so I’m picking a random post from him at a quick search for “custom.cfg”:

Duplicate boot entries in Grub

For more than one Garuda OS I use the simple /boot/grub/custom.cfg Tutorials in web, search for gohlip or Chrysostomus menuentry "Garuda Linux i3wm auf nvme0n1p2" { insmod btrfs search --no-floppy --fs-uuid --set=root 35075ddb-bcf7-47aa-a43a-e759a082af57 configfile /@/boot/grub/grub.cfg } menuentry "Garuda Linux KDE auf sdb2" { insmod btrfs search --no-floppy --fs-uuid --set=root 95b9d929-b8bc-4eab-b19c-6026a70aa6b9 configfile /@/boot/grub/grub.cfg } menuentry …

I think the context is clear anyway.
A few words are mentioned here:
https://wiki.archlinux.org/title/GRUB#Generate_the_main_configuration_file
Note e.g.

Changes to /boot/grub/custom.cfg do not require re-running grub-mkconfig, since /etc/grub.d/41_custom adds the necessary source statement to the generated configuration file.

Which is quite useful in my opinion.