I got a buddy that has a 2017 CX-5. Has ALL the bells and whistle available at the time. He cannot play tunes from flash drive. Only bluetooth. His manual says the usb power outlets are for charging only and cannot be used to connect to vehicle audio system. See pic.
My other buddy's 2010 Camry Hybrid plays from flash drive flawlessly. Can even pull flash drive out, turn off car and reinsert. Picks up where left off.
Because you didn't get the upgrade. Neither did I. Mine will keep the phone charged at its current level... prevents drain... but adds nothing.That's odd. My 2016.5 won't charge my phone but it plays USB music just fine. It also plays music streamed through my phone fine as well. The phone can be connected via Bluetooth or with a cable.