As you probably already know, the front USB ports are the only one that work with a USB key for music. This "uses up" one of them as far as charging goes. I experimented and found that this cable solves the issue: https://www.amazon.com/gp/product/B01KX4TKH6/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1 One side of that cable delivers power, the other side delivers data. So, plug that into the USB port, plug your phone charging cable into the power side and the USB key into the data side. It easily tucks in the space below the phone dock. End result is that you can have 2 phone charging ports and USB music.