FYI Had similar problem with older Dagu and newer software. Turned out to be ino file was too big so trimmed out sensor and encoder code so it would compile and download to dagu mini driver board. Maybe the newer firmware takes up less room. I have not tried updating firmware so not sure if this will work for me. See my post below for details. http://forum.dawnrobotics.co.uk/viewtopic.php?f=5&t=1332