The call to PIOS_I2C_CheckClear() will always fail as the MPU6050 thread is already running and using the I2C bus. (as discussed here : https://groups.google.com/forum/#!searchin/phoenixpilot/PIOS_I2C_CheckClear/phoenixpilot/MG6H0khdssU/6odiRWIuStsJ). This correction has never been pushed.