Default Home and Power buttons not working

I recently flashed a Phoenix ROM and it could be coincidence but my hardware Home button is now not responding to presses most of the time. It will always wake the screen from sleep when I press it, but it will not return me to the Home screen when I'm in an app. The power button also doesn't respond to long presses, so I have no easy way of rebooting.
Is this likely to be a Phoenix-specific problem, or can anyone think of any other reason for it?