We caught a small bug in the attiny code that runs the failsafe on ArduPilot and ArduPilot Pro. On ArduPilot, the failsafe will allow you to reboot the main microcontroller remotely, and this was stuck in the on position, making it impossible to load the autopilot code. Corrected Attiny code is here (if all you want is the hex file to load onto the attiny, it's in the Defualt folder).