I have a phantom 2 that was working perfectly fine for the first 10 flights or so.Then the first thing I noticed going wrong it wasn't holding position very well.Now it just takes off. Twice I was able to recover it one time it had a hard landing
Phantom 2 model #P330Z with H3-3D gimbal.After having this problem we downloaded the latest firmware.After the hard landing we noticed the gimbal was chattering when lean to one side so we straightened and downloaded new gimbal software problem seems to have gone away on the gimbal end of it.Still have having the fly a way problem . I'm also using fat shark predator v2.
The IMU calibration is not a download but an important process if you crash. Set the Phantom down on a firm, dead flat surface, plug in the USB cable and follow the instructions in the assistant software. I would do a full calibration rather than the basic. If you are unsure, have a search on the forum for full instructions.