Grub ssd iso boot fails from no support filesystem image found at /live

[darylbubba]

I am using Ubuntu. I am slowly learning how to boot isos from the hard drive using the grub menu. I have been successful with ubuntu, gparted, foxclone and a few others. Debian is giving me a hard time. I read that the 40_custom script is completely different for a Debian iso. Here is the script I have at this time...

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 # debian ISO grub boot
menuentry "Debian" {
echo 'looking for ISO on hd0,6'
loopback loop (hd0,6)/boot/ISO/debian-live-11.6.0-amd64-gnome.iso
echo 'found for ISO on hd0,6'
linux (loop)/live/vmlinuz-5.10.0-20-amd64 isofrom=/dev/disk/by-uuid/abaaa079-bd5-4546-aff2-6ce4adfaee9d/debian-live-11.6.0-amd64-gnome.iso boot=live components
 quiet splash --
initrd (loop)/live/initrd.img-5.10.0-20-amd64

It boots to the splash screen but then goes to the "initramfs" prompt. I then enter "exit" and get the message

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no supported filesystem iso found at /live 

What is my problem?

[darylbubba]

I have found a different script at

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https://www.linuxbabe.com/debian/boot-debian-9-iso-from-hard-drive-grub2

that works better. Here is the script

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 # debian better script
menuentry "debian-live-11.6.0-amd64-gnome.iso" {
        insmod ext2
        set root='(hd0,6)'
        linux /boot/ISO/vmlinuz
        initrd /boot/ISO/initrd.gz
}

This one uses a couple of different elements AND it requires putting the vmlinuz and initrd modules into the directory that holds the iso instead of using the modules inside of the iso. The problem I have with this script is that even though it does start out looking better it jumps right into the installation mode instead of "try it out first" mode.
I'm hoping someone out there can help me with this.
p.s. A while back I did have a script that successfully booted a debian iso from my hard drive but I think it was an older version of debian. I will see if I can find out what I had and try to repeat it.

[panpan]

I think the easiest way is this.
https://www.ubuntubuzz.com/2015/05/easi ... escue.html

[darylbubba]

I have installed grml-rescueboot and it works great for booting ISOs stored in /boot/grml.
A couple of questions...
1) What is the difference between grml and grml-rescueboot?
2) GRML-rescueboot can be installed on a usb stick (from what I have read) or install on a working operating system, which is what I did. But it seems to me that grml-rescueboot should be properly named grml-isoboot since it doesn't actually rescue anything but it does boot an iso. Am I missing something? If grml-rescueboot is install and run on a usb stick does it have other options that I am not currently seeing? I mean, if my system crashed I don't think I would be able to boot anything from grml-rescueboot since my system would be non-functional.
I'm not complaining, I like it a lot. I just wonder if I am seeing things differently than I should be seeing them.