But you have not checked if the telephone audio actually is there? I'm just wondering if the BT mutes the audio signal for some reason i.e. it is waiting for the DSP-amp bus signal. So coding would fix this. Also, it may be that the radio still requires coding to actually activate the telephone input. There are weird stuff in this radio, for example the AUX-input appears only after you connect a 300Kohm resistor between input pins. That is if you use a DIY-solution, not the original BMW retrofit cable.