MPU-9150 Software Product Revision wrong

I'm in the process of porting eMPL to TI LM4F120 to interface with an MPU-9150. inv_mpu's mpu_init() function due to "unsupported revision number when it checks.

In an effort to debug this I've exampled the I2C bus cycles and verified with a protocol analyzer that all seem right. The MPU register being read from is 0x06, but I can't find this documented anywhere.

1) When I example the rev variable in mpu_init(), which has the rev number after masking, it reads 7 and that's not valid according to the code. Can someone help me understand this and how to resolve it?

2) Can someone explain the purpose for the other undocumented registers, 0x00..0x0C? Or, where are these documented?

Thanks