I've looked all around every board I know of and in the Copter wiki and no where does it mention this error. I just updated to 3.4.6 from 3.3.3 (company drones...slow). It would not let me start the coptor until I went in and added a Takeoff command line. Our missions are built using another software that does not see fit to make takeoff the first command. Can anyone point me to documentation on this? Or tell me if it is a "new thing"? 3.3.3 and 3.4.6 are 1.5 years apart soooooo....yeah, it could be new!
This problem was discovered after we could not place the copter in Auto mode where the only difference (confirmed by a parameter file comparison) was that the copter that would arm and takeoff was 3.3.3 firmware while the one that refused to arm and takeoff was 3.4.6.