Not exactly cause for joy, but still pleased that it is necessary not only to me. There is a good chance to get a solution to your problem ...Wow, I was about to post the same because I was impressed someone managed to change gyroscope values. Yes, I have the same problem, my spanish smartphone comes with the X axis inverted, so the sensor fusion makes strange things (gyroscope and magnetometer/accelerometer read oppossite values), although I think this could be another app instead of adding it to your noise filter one (because in my phone there's no jittery, only a changed axis. It could be solved by the developers, but at this time there's no patch).
Thanks a lot!
I have a problem with ZOPO ZP998. This "flagship" ZOPO of 2014, which cost, by the way more than my monthly income.
Just for reference, what is your device, buddy?