Hi Rowland. The USB ports are currently only available for engineer software maintenance but they are available to YouView and the device manufacturers to support new features that will be added in future software updates.
Most other boxes make use of the USB port for importing and exporting programmes, music, photos etc. This is what the Humax HDR box does and is a serious omission from the YouView box. It is absurd to have the ports and not allow their use - until the hackers get going?