By the way, a 0 byte "overlay"? # mkinitramfs -o /tmp/foo2 -k Working files in /tmp/mkinitramfs_8JZYvN and overlay in /tmp/mkinitramfs-OL_aFgfUj # find /tmp/mkinitramfs_8JZYvN|wc -l 160 # ls -l /tmp/mkinitramfs-OL_aFgfUj -rw------- 1 root root 0 2010-04-07 12:22 /tmp/mkinitramfs-OL_aFgfUj