in readBytes() in I2Cdev.cpp the register to read from is written and then before reading the actual value a new transmission is started.
This is not working for the MPR121.
Currently it does this:
Wire.requestFrom(devAddr, (uint8_t)min(length - k, BUFFER_LENGTH));
Here is explained that the endTransmission is needed to actually send the regAddr.
But this is not working for the MPR121 because I guess it forgets the register you want to read from when the transmission is c