I have this problem with my system.
after updating it , it can not play loud . Only low as can be heard in the video,
huh can I do here ?
video :
i have updated by this guide here : http://avic411.com/index.php?/topic/37407-2013-eu-update-f30-f930-f9310-f40-f940-f840-f8430/
everything works fine, it's only bluetooth is not working properly and have tried other mobiles but is the same