sudo nano /etc/grub.d/40_custom && sudo update-grub2
 menuentry "Ubuntu ISO" { set isofile="/home/isos/ubuntu.iso" loopback loop $isofile linux (loop)/casper/vmlinuz.efi boot=casper iso-scan/filename=$isofile noprompt noeject toram initrd (loop)/casper/initrd.lz }