I have seen a few people having the same problem, but none of the issues seem to match mine... I have been trying to get FPV working, while doing this I needed to upgrade the SW in the transmitter to enable forwarding of the pitch control to the NAZA. At the same time I switched to 9" props to handle the weight better (also added dual batteries). First flight it was a bit windy and the quad acted quite weird in the air, it touched the ground quite heavily at one point, breaking the usb connector on my go pro (that was sending images to the FPV) but the quad recovered and stayed in the air. I landed and the next time I took it up I decided to not run it with the gimbal or the dual batteries, just to make sure it was still ok. I switched back to original props as well. As soon as I tried to take of, it tipped over and destroyed one of the props. I recalibrated it, replaced the broken prop and tried again, same result. I then tried a 3:rd time with a recalibration after having connected it to a computer and checked the compass calibration, but it all seemed to have good values. I then tried a takeoff in attitude mode instead, since that would eliminate any potential compass issues as I understand it, but it had the same result, another prop busted. I'm so incredibly frustrated now, I just want to get it back into tha air! Any tips would be greatly appreciated!