I upgraded my DJI 550 with Naza v2 to 4.0 a few days ago. For me it's been a mixed bag. BTW, I'm a very green pilot.
Pros:
1. I can now reliably get in to compass calibration mode. With 3.16 I usually couldn't.
2. Maybe, just maybe, I have more time to get into advanced calibration mode after plugging the battery in before the stupid "too hot you need to cool down" error comes up.
Cons:
1. It got stuck at the Flight Limit spot. I'd set the altitude and distance Flight Limits to 100 meters and forgot about it. Until, that is, I hit the limit and it "seemed" not to respond to my control. I say seemed because it was near a tree line, I was near the end of my battery and I can't eliminate pilot panic as a contributing factor. I resorted to forcing fail-safe by turning my transmitter off. It returned home and I was able regain control and land it.
2. The GPS hold works sporadically. I always fly in GPS mode. Although I flew several batteries worth of flights without issues I've had episodic problems with it failing to hold a hover.
Sometimes the flight starts out with it hovering well but then losing its ability. By losing I mean that it will develop a horizontal drift, sometimes minor but sometimes more rapid.
Other times it has that drift right at takeoff.
I've repeated the compass calibration and advance calibration many times and that hasn't fixed the problem.
The last time I flew it the failure to maintain hold ended with a crash that broke my landing gear so I'm dead in the water till spares come in.
Anyone else experience this? I'm clueless as to what to do.