There was a thread on Linux Questions years ago about this exact topic. I managed to get Grub to boot multiple Debian Live iso images but ended up testing various applications from Pendrive Linux simply because everything was automated. I haven't tried with the new iso made with Live Wrapper so there may be a few differences.
On 06/04/2018, Thomas Schmitt <scdbac...@gmx.net> wrote: > Hi, > > Narcis Garcia wrote: >> I've tried this with no luck: >> iso_path="/debian-live-9.4.0-amd64-gnome.iso" >> linux /live/vmlinuz-4.9.0-6-amd64 boot=live components >> "${loopback}" >> initrd /live/initrd.img-4.9.0-6-amd64 >> >> Results in: >> [...] ... mounted filesystem... > > So GRUB obviously found the ISO and started the kernel with that initrd. > > >> (initramfs) Unable to find a medium containing a live file system > > A possible emitter of this message is in the initrd inside the ISO. > > gunzip < /mnt/iso/live/initrd.img-4.9.0-6-amd64 | strings | less > > produces the string > Unable to find a medium containing a live file system > and leads me via "livefs_root", "find_livefs", "check_dev" to > fromiso= > > Dunno whether > https://manpages.debian.org/testing/live-boot-doc/live-boot.7.en.html > is applicable to debian-live-9.4.0-amd64-gnome.iso, but it has > > findiso=/PATH/TO/IMAGE > Look for the specified ISO file on all disks where it usually looks > for the .squashfs file (so you don't have to know the device name > as in fromiso=....). > > fromiso=/PATH/TO/IMAGE > Use a filesystem from within an ISO image that's available on > live-media. > > If this does not yield insight, then one will have to unpack the compressed > cpio archive initrd.img-4.9.0-6-amd64, to identify the script that bears > the > code about "Unable to find a medium containing a live file system", and > to find out how to make it accept a ISO image file instead of e.g. a CD-ROM > device. > > > Have a nice day :) > > Thomas > >