Hi,

It looks like an accelerometer hardware problem.

I experienced some strange behaviors like this recently probably caused by an accidental drop of my phone. I had to lock the phone in portrait mode to use it...

By using a level app and the sensor galery I noticed a constant shift of -90° on the X axis. I don't know if it was a calibration issue or if the accelerometer could have made a rotation in the phone .

BTW, as I didn't want to use the Nokia care services, I manage to fix it by patching sensord. I added a constant shift of the X axis in the libaccelerometeradaptor and now everything is working fine again.

Can you install the sensor galery app and told us what results the QAccelerometer sensor gives you when your phone lies flat on a table ? The level app can help too...

https://projects.developer.nokia.com/sensorgallery