To use this facility, a pull-up resistor (1k to 3v3) should be fitted to GPIO pin 26. Shutdown is initiated by grounding pin 26 continuously for over one second. The facility is disabled by default; to enable it, go to the console menu and select Settings, Hardware Shutdown, and press the space bar to mark "SHUTDOWN". PLEASE NOTE THAT INSTALLATION OF THIS FACILITY REQUIRES A NEW CARD BUILD - IT IS NOT AVAILABLE AS AN UPDATE.
On the same settings menu, I have added the ability to display the on-screen debug menu and to select the response to the Power button.
Lastly, I have added another remote control to the Library, from the Opticum HD AX150 Satellite Receiver.
Thanks to Shaun G8VPG for asking for the hardware shutdown and to Thomas DL5BCA for the remote control information.
Please report any bugs here