For reasons unrelated to the question, I've had to take off a landing leg with a compass in it, and replace it with a brand new one (I now have a spare white compass leg with apparently the new style compass if anyone wants one). This has meant that I've had to open the shell, disconnect the GPS unit, unplug the existing compass leg, plug in a new compass leg and then re-plug in the GPS, and of course put it all back together again. I'm going to redo the compass dance, I'd probably do that as a matter of course after any kind of operation on the machine, but I'm not sure if I also need to recalibrate the UMI after that kind of a change. It's not a huge issue if I do have to, but it's just a challenge finding a truly perfectly flat surface to do it on. Certainly difficult in my house, and even more so outside. I'm inclined to do it anyway, regardless of the hassle, but would just be interested to know if it's actually necessary, or most likely a waste of my time. And if you're interested in why a new leg was needed; when I bought the P2 it was hydrodipped in carbon-fibre-effect. However, the newer compass that DJI had apparently released (or something like that according to the seller) wasn't available yet in the carbon effect leg, so they had to give me the P2 with one plain white leg so it would have the newer compass, and order me in at their expense, a carbon-effect one with the new compass. It only took like 3 months to arrive!!!! But, finally it arrived, and I was able to finally have matching legs (almost matching, the damned thing has a very slightly DIFFERENT carbon-effect pattern, but at least it's ALMOST the same. A plain white one stood out like dog's proverbials). I took off the plain white one - now spare - and put on the almost matching one today. Also the first time I've had the guts to open the shell. Wasn't as scary as I thought it was going to be.