After updating to the latest version, and playing around with the flight simulator for a while, I was going to update some settings when I noticed a compass calibration warning. The calibration didn't seem to work in my office so I took it outside where I also noticed an IMU update warning which I knew I should do first. After setting the Mavic on a flat surface as shown on the calibration screen I started the calibration. It ran fine until the progress bar reached about 1/4" from the end and stopped. The green and one blue light were lit in the bottom left quadrant of the screen. The number 2 appeared at the bottom right corner. I left it running undisturbed for about 10 minutes; no change. I resorted to shutting down the drone, then the controller, then started all over again with the same result. I used about 20% of the battery trying. What do I do?