I am new to the Nano+. After updating the firmware it directed me to calibrate the compass and calibrate the IMU. The compass was easy enough but its refusing to calibrate the IMU. I have it on a perfectly level wooden surface. I even got out my level to make sure the surface was level. it never gets past the first section. It gets up to about 5% of step 1 and then says it failed and retry. I did this 4 times but the battery section started getting hot (I am assuming from being on the ground and not flying in the air so the fan works properly) so I stopped. Any suggestions? Or does it really need to be done?