While we're sharing, here's the script I use for the same purpose. It outputs hex and ASCII bytes rather than bits. #!/bin/sh hexdump -C $1 > /tmp/$1.hexdump hexdump -C $2 > /tmp/$2.hexdump diff /tmp/$1.hexdump /tmp/$2.hexdump | less rm /tmp/$1.hexdump /tmp/$2.hexdump Usage: ./hexdiff.sh original.img changed.img Tom KD7LXL