To install firmware, follow these steps:
Note that the firmware uploading will reset your settings. We
suggest that you save them before the firmware upload, so that you can
reload them afterwards. Also we advise that you take special care over
the volume control if you normally use it. Make sure that you re-assign
the volume control and turn it down before playing audio. Disconnect the power lead from your box. Hold down both the standby button and the volume encoder button whilst reconnecting the power. LEDs will remain off. Ensure that the USB cable is connected to the host computer. Run the Prism Sound USB control app. You should see the bootloader dialogue pop up. Click 'Browse' & select a firmware file. Click 'Load'. When the load is completed, restart the box by clicking 'Launch'. Reload your settings, and check the operation of the volume control before playing any audio.