see: https://wiki.ubuntuusers.de/GRUB_2/Skripte/

# for /boot/grub/grub.cfg

**********
***     1

set default=0
set timeout=5
set root=(hd0,1)

menuentry "Debian-Lenny-2.6.32-3-amd64 (vgraid)" {
        linux   /boot/vmlinuz-2.6.32-3-amd64 root=/dev/mapper/vgraid-lenny ro
        initrd  /boot/initrd.img-2.6.32-3-amd64
}

menuentry "SystemRescueCd (isoloop)" {
        loopback loop /systemrescuecd-x86-x.y.z.iso
        linux (loop)/isolinux/rescue32 isoloop=systemrescuecd-x86-x.y.z.iso
        initrd (loop)/isolinux/initram.igz
}

**********
***     2