Most iConnectivity interfaces have more than one USB port. However you can only use one of these ports to perform a firmware upgrade. This list shows which port on each interface that can be used to upgrade that firmware:
mio2 - USB Device Port 2(front)
mio4 - USB Device Port 2 (back)
mio10 -USB Device Port 1 (back)
MIDI2+ - USB Device Port 2 (front)
MIDI4+ - USB Device Port 3 (back)
ConnectAUDIO2|4 - USB Device Port 1(back)
AUDIO2+ - USB Device Port 1 "power"( back)
AUDIO4+ - USB Device Port 1
PlayAUDIO12 - USB Device Jack 1 (front)
