Problem with a new MPU9150 MotionFit Wireless SDK

I received last Friday one MPU9150 MotionFit Wireless SDK after a long wait for the availability. After the battery charging period I tried to check the board functionality using the teapot demo application included in the MotionFit
Wireless SDK v5.1 zip file dowloaded from download section of the web site. Unexpectedly it did not work correctly. The teapot appeared and dissapeared continuously in different positions with very little changes (few degrees) in the board orientation.
After installation of Python environment I checked also the second demo with cube and console (always from the same zip file) and also in this case the app did not work (cube still in a random position and console showing continuosly the messagge "serial misaligned". During these tests, apparently the board showed to work, blue led on during movement and off after some time of no movement. After this frustrating beginning trying to understand the issue I have found in the dowload section of the web site also an older teapot application named TeaPot and Pointer Demo App. Surprisingly it worked and I was able to rotate the teapot smoothly and coherently with the board movement. Only the starting point of the teapot was not as described.
At the same way I tried the Cube demo using the older "UC3 Debug Console" SW from Download section and also in this case it worked (at least the cube, I waas not able to send command through the console to get different sensor data).
I expected the last firmware is in the MPU9150 MotionFit Wireless SDK interfacing the application SW included in the MotionFit Wireless SDK v5.1 zip, but this seems to be not true.
Is there something wrong in the loaded firmware or is it correct that I have to use the old demo applicative SW ?
Thanks a lot in advance for any help on this issue