There have been no hardware changes, and the latest software can be downloaded and installed at any time as long as the device is connected to a computer via usb. So any HD500, whether brand new or used, should perform as if brand new UNLESS there has been a hardware failure in the used device. If the device is out of warranty then the repair would cost you. But if your friend says all hardware is OK, and you trust him, the HD500 should perform as if it were brand new.