Occassionally I accidentally press one of the input buttons on the remote - my unit is ony 1 input. The only way I have been able to get out of this state is to unplug the unit from 12V power supply and then repower it. Am I missing something?
Yep. Here's what your're missing.
Let's say the LDR3x is on input #1 (call it the default input) and you happen to press the Input #2 button (one of 3 top row input select buttons). The unit will immediately mute and the status light will blink. At that point you can change your mind and choose input #3 instead. Or #1 again. When you're done choosing, you press the Enter button to cofirm/lock in your selection, the unit unmutes ramping back up to prior volume setting unless the volume was past 50% (step 35) in which case it tops out at step 35.
Of course if you only have 1 input and no input select relaying, all that's happening is you are muting the unit. But unlike normal muting, the unit is now in Input Change Mode and needs its Enter button pressed to unmute.
So, boiled down, if you accidentally hit a Input Select button, just press the Enter button.