We fixed some bugs in the ArduPilot's failsafe code, which runs on the board's second processor, an Attiny45. It now works great, and has a secret "reboot the autopilot" feature. Just toggle the autopilot enable switch on your transmitter five times fast, and it will reset the Atmega168. Great for times when you don't want to land just because a random bug froze the autopilot. Otherwise it just does what it's supposed to do: transfer control from RC to autopilot and back again on command--every time, without fail.
The new code (source and everything) is here. If all you want is the hex file to load on the Attiny in AVR Studio, it's here.