Something I noticed the other day and want to share. It is about initiating compass cal with S1. The manual states: "Quickly flip the switch S1 position 1 -> position 3 -> position 1, five times or above". Well I noticed that you only need to flip it position 1 -> position 2 -> position 1, exactly five times ending on position 1. It will enter cal mode every time. If you want to cancel after solid yellow, flip once position 2 -> position 1. And you don't need to flip it super fast frantically. A half second at each position works. And of course you can only initiate cal with motors off. And I know about the app way to initiate calibration.