menuentry "Ubuntu 16.04 Desktop" --class ubuntu {
  set isopath="/home/mark/Downloads" 
  set isoname="ubuntu-16.04"
  set isofile="${isopath}/${isoname}"
  echo "Using ${isoname}..."
  loopback loop $isofile
  linux (loop)/casper/vmlinuz.efi boot=casper iso-scan/filename=${isofile}
  initrd (loop)/casper/initrd.lz
}