I have a Spark that I’ve hadn’t flown in a year since moving. This drone was never crashed and never mishandled. It worked perfectly when I last flew the craft. When I tried it out I was instructed to update the firmware on both the Spark and the controller and after that the IMU would not calibrate. I tried everything but no success. I returned the unit to DJI and paid $74 to have the IMU replaced but I still wonder what happened. This drone has suffered no trauma. I noticed on several other forums several others seem to have had their IMU fail for no reason and the solution was always send it in for repair. I’ve never heard an explanation as to why these failures are happening to units that have suffered no apparent damage. Anybody know something I don’t?