I've had my Humax pvr about 3 months and having similiar problems. Got it connected to my Panasonic via HDMI. I usually switch on panasonic then Humax wait nearly 1 min (is this normal?) until it boots up and eventually switches on.
Unfortunately now I have to try several times before it works. The Humax is on but the TV doesn't show it on screen. Even if I go to tv and set it to display HDMI input, it still doesn't work. I have to turn everything off and about 3rd attempt it works.
It's times like these I miss the sky+ box that fired immediately and I didn't miss a thing between digital tv and Sky channels.
Other problems that have started - forgets to record pre-set series of programmes that I've set or says recording failed. Also, the other day I clicked record button while watching a programme went off to do something else, only to discover it was still recording that same channel next morning

Will check other threads to see if anyone else is having these problems.