I have a H9 Twin running OpenATV 6.3 and latest Wooshbuild.
There doesn't appear to be a clock option for the front LCD panel so I installed the plugin extension 'permanentvfdclock'.
This has a clock that runs fine while the box is on but as soon as I put the box in standby the clock freezes...
These are a good alternative to pulling the plug when trying to power off the HD51.
It's just a power switch that fits between the power cord and socket.
DC 12V Inline Switch Cable On/Off Rocker Switch DC Jack 5.5mmx2.1mm Male to Female Connector