My friend has a 2015 Mazda6. We are having problems getting tunes to play via usb flash drive. USB greyed out on display. Cannot select. Car is not equipped with Mazda Connect. Is this required to to play audio from flash drive? I read a lot about usb taking long time to load but nothing about not working at all. This flash drive works well in my 3rd gen Tacoma but not in his Mazda6. A little bit of relevant info may keep me from barking up the wrong tree. How about firmware, will this car accept upgrade?