After going thru all of the possible combo of things, to include firmware updates, etc. , the IMU calibration continued to hang and never complete. Ugh. Finally saw noticed that upon completion of a position rapid green lights flashing meant completion of that series. Well, left tilt completed, right tilt completed, but would hang up on position where you saw top of drone, and camera pointed towards you. I then started tilting back, green rapid flash, tilt forward, green rapid flash, and went thru all positions, NOT MENTIONED IN IMU CALIBRATION INSTRUCTIONS, and, after all showed rapid green flash, IMU calibration completed and all is good.

Hi there. Thank you for reaching out and we do apologize for the trouble. Can you please confirm what specific Phantom series drone are you currently using? Does the unit experience a hard landing before? Please keep us posted. Thank you.

Phantom 4, Pro Advanced 2.0. No hard landings, nothing unusual during flight nor landing(s). As I indicated in my first post, after many attempts at getting pas the position where the bird is horizontal, and camera facing me, it 'hung up', but the green lights rapidly flashing indicated completion. I then continued to move thru all axes e.g. tilting forward (green blinks), backward, (green blinks) and eventually IMU calibration completed.

jpalamaro Posted at 5-15 04:46
Phantom 4, Pro Advanced 2.0. No hard landings, nothing unusual during flight nor landing(s). As I indicated in my first post, after many attempts at getting pas the position where the bird is horizontal, and camera facing me, it 'hung up', but the green lights rapidly flashing indicated completion. I then continued to move thru all axes e.g. tilting forward (green blinks), backward, (green blinks) and eventually IMU calibration completed.

Hi, jpalamaro. Sorry for the late response. We're glad that you managed to isolate the issue and share with us the steps that you take. Should you have other inquiries, please don't hesitate to reach us. Thank you for your valued support.

Using your help, I'm at 6/6 and it is still doing something.  How long did it take you?  Thanks for your suggestions!