<wiiplayer2|m> To build the empty dtbo:
<wiiplayer2|m>  mkdir $out
<wiiplayer2|m> dd if=/dev/zero of=$out/empty_dtbo.img count=1
<wiiplayer2|m> avbtool add_hash_footer --partition_name dtbo --partition_size 2621440 --image $out/empty_dtbo.img
<wiiplayer2|m>