Recently I crashed my P3 Standard (hit a bush about 4 feet off the ground-no damage to exterior or camera). Immediately after the crash I flew it without difficulty but during RTH got a verbal message that there was a compass error and a red box appeared the message of which I couldn't make out.  I switched to Atti and landed it without event. Afterwards my numerous attempts to recalibrate the compass have failed (many different locations all of which seemed acceptable to the app).
I updated the firmware which I thought I may have screwed up (think I disconnected the P3 before the update was complete however upon turning it back on got a message that the update was complete. The app tells me the firmwhere is up to date.
I still can't calibrate the compass, however the aircraft status box will turn green and say "ready to fly GPS" (I think it usually says "safe to fly GPS"). With quite a bit of apprehension I took it up for a flight which appeared to go well. I flew it in GPS and Atti. RTH was flawless. Though it was a successful flight I don't trust flying it without a calibrated compass.
Anyone have advice?
Thanks

First check the Sensors tab in the app settings.
What does it show for the compass?

When you look at Compass and IMU Sensor readings, what are the readouts?

Recalibrate IMU when aircraft and battery are COLD, then recalibrate Compass outdoors, not indoors, making sure you are well away from metal structures and concrete (rebar).

Disconnecting before the update was complete could still be causing the problem.  Reinstall the update, regardless of the app saying update is complete.

Don't fly the aircraft until you have good readings on IMU and Compass.

Thank you all for the advice. I'll post after I've tried your advice.

Harley's proxy Posted at 2016-10-26 07:35
Thank you all for the advice. I'll post after I've tried your advice.

Your problem is compass, not IMU.
They are unrelated so there's no need to recalibrate the IMU.
If your sensor data shows nothing for the compass, that indicates the compass is broken or disconnected.

labroides@yahoo Posted at 2016-10-25 07:43
First check the Sensors tab in the app settings.
What does it show for the compass?

Sensors (all of them) are twitching. Readout numbers constantly vasilate. Don't know if thats normal?