A grub menu to boot Ubuntu Focal arm server version beta image via netboot

grub.cfg

set menu_color_normal=white/black
set menu_color_highlight=black/light-gray
if background_color 44,0,30,0; then
  clear
fi

insmod gzio

set timeout=5
menuentry "Install Ubuntu Server (Focal Beta) (Pull the iso from web)" {
	set gfxpayload=keep
	linux	/casper/vmlinuz url=http://cdimage.ubuntu.com/ubuntu/releases/20.04/beta/ubuntu-20.04-beta-live-server-arm64.iso only-ubiquity ip=dhcp ---
	initrd	/casper/initrd
}
menuentry "Install Ubuntu Server (Focal Beta) (Pull the iso from lab apache)" {
	set gfxpayload=keep
	linux	/casper/vmlinuz url=http://<your Apache IP>/ubuntu-20.04-beta-live-server-arm64.iso only-ubiquity ip=dhcp ---
	initrd	/casper/initrd
}