Pixhawk jumping back and forth between green and yellow

Hoping someone can advise here. I have this issue which sometimes comes up sometimes and it can be very frustrating as it prevents me from arming. Basically the Pixhawk jumps back and forth between flashing green (ready to arm) and flashing yellow.

Sometimes moving the aircraft seems to trigger a change between green and yellow and sometimes it will just change whilst sitting still. If I try to arm whilst it is flashing yellow, then I get the “pre-arm compasses inconsistent” message, so the clue may be there. However, why is it going back and forth?? I can confirm this is not to do with magnetic interference from ferrous metals around the aircraft.

Here is a short video showing the issue: https://www.youtube.com/watch?v=le_2cgYj4T0


Ok, so I’ve found a work around by disabling the internal compass and that solved things straight away.

I would prefer to be using both, though, assuming that gives some failover/redundancy.

Did you re-do the compass calibration? Sometimes the calibration changes if you change the aircraft configuration or payload. Also be mindful of the compass offsets, you don’t need much of a magnetic source if it’s close enough to the autopilot, I had a magnetized steel 4-40 screw cause unacceptable offsets and compass variances because it was right underneath the Pixhawk.