I am new to this forum...thought it would be a good idea since we just bought a 2014 337. Regarding the USB on the Furrion Stereo, we had the exact same problem. In my truck, I simply plug in a flash drive that has all of my music on it, and never had a problem. When we first looked at the Reflection and saw the USB port, we assumed that it would operate the same way. With about 1000 songs on the flash drive, what a space saver -vs- multiple CD's. Just like Tucson Jim, we had to use an auxillary jack to enjoy the music from our I-phones. The explanation we got from Grand Design has never resonated with me...if I ever get one that makes sense, I will share it! This would definitely be a great feature in the GD products if the flash drive would work like my truck.