Boot ubuntu iso file

grub.cfg

set menu_color_normal=white/black
set menu_color_highlight=black/light-gray

# File name of ISO file
set ubu_path=/ubuntu-16.04-desktop-amd64.iso



menuentry "Try Ubuntu without installing Failsafe" {
# Search for iso file in all paritions and set the partition as root
	search -f -s root $ubu_path

# Create a new loopback ( virtual drive ) from is file 
	loopback loop0 ${ubu_path}

# Set new loopback device as root
	set root=(loop0)
	
	set gfxpayload=keep
	linux	/casper/vmlinuz.efi  file=/cdrom/preseed/ubuntu.seed boot=casper iso-scan/filename=${ubu_path} vga=normal
	initrd	/casper/initrd.lz
}