I've asked a solution and read a good one for ext2, but it does not work in my ext4 AMD64.
It is in spanish, you can translate with google translate or any other or even read only the commands.

http://usemoslinux.blogspot.com/2010...esde.html#more

In ext2, more or less the entry must be

menuentry "Lubuntu Live" {
set root=(hd0,5)
loopback loop /vbox/lubuntu-10.10.iso
linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=/vbox/lubuntu-10.10.iso --
initrd (loop)/casper/initrd.lz
}

but in ext4, it gives me an error of

file not found
you must load kernel first
even i changed, after an ls in GRUB the hd0.5 by hd0.msdos5, in my case hd0.msdos1, but with upper simple commas as in the main kernel entry.

I think there would be an easy way of adding ISO rescue - or prove - images to GRUB menu from the program in system/administration/boot manager, but in the meantime, a section in GRUB ubuntu main page explaining how to do this in ext2 - as I post - and in ext4 - as I ask someone to explain me how to do -


My 40_custom, where only works Ubuntu entry is:



#!/bin/sh

exec tail -n +3 $0

# This file provides an easy way to add custom menu entries. Simply type the

# menu entries you want to add after this comment. Be careful not to change

# the 'exec tail' line above.



menuentry "Ubuntu, with Linux 2.6.35-23-generic" --class ubuntu --class gnu-linux --class gnu --class os {

recordfail

insmod part_msdos

insmod ext2

set root='(hd0,msdos1)'

search --no-floppy --fs-uuid --set c617a74c-d199-49fc-997e-77ebbe33a8bb

linux /boot/vmlinuz-2.6.35-23-generic root=UUID=c617a74c-d199-49fc-997e-77ebbe33a8bb ro quiet splash nomodeset # video=uvesafb:mode_option=>>1024x768-24<<,mtrr=3,scroll=ywrap

initrd /boot/initrd.img-2.6.35-23-generic

}

menuentry "Rescatux" {

recordfail

insmod part_msdos

insmod ext2

set root='(hd0,msdos1)'

loopback loop /isos/rescatux.iso

linux (loop)/casper/vmlinuz boot=casper locale=es_ES bootkbd=es console-setup/layoutcode=es quiet splash iso-scan/filename=/isos/rescatux.iso --

initrd (loop)/casper/initrd.lz

}



menuentry "rescatux2" {

set root='(hd0,msdos1)'

loopback loop /isos/rescatux.iso

linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=/isos/rescatux.iso --

initrd (loop)/casper/initrd.lz

}