About 4 weeks ago I updated to latest firmware to get my PP3 back in the air after a long winter's nap. I Had gave it a test flight before updating and all was well. I updated at my usual spot then moved the PP3 to my table where I always do my IMU updates so as to not have magnetic interference, vibration issues, out of level etc. It has always performed well there and never caused me an issue. My problem this time though is that the update "started" but never went anywhere. It doesn't start scaling in the app to show percentage, it doesn't show anything in the app at all. It just sits there and flashes the LED's in the normal yellowish update mode when doing IMU calibration. I have tried many things, even going so far as to refrigerate the craft and batteries to get it cold enough (never an issue before). I have tried installing the app on both Android and IOS devices but still get same error with the no display of progress in IMU calibration. I have tried to get old firmware back on the craft, but it will not accept any downgrade. I am at a loss how to get this to complete or get old firmware back on the craft. I can not get it to start motors or anything and no errors are displayed.... it is just stuck in IMU calibration. Anyone have ideas I can try that I haven't yet?