My latest 4K box, a few months old has had to be replaced. 3rd or 4th box ( 1 HD, 3??x4K) in 2 years. The most recent tech told me that because I am running it through my Onkyo TX-NR636, he thinks that when the PVR is updated from the Telus end, that the PVR can't see my tv and eventually this is what causes the fuzzy white screen/shutdown/unable to reboot issues. It now runs direct into my tv on a different input.
Had a tech a couple of PVR's ago say that it was a bad run of manufacturing, because he was seeing it a lot. The box that came today is a whole new model.
I'm inclined to think that a whole bunch of bad hardware was being used up until it ran out.
While a first world problem, instead of my beautiful receiver using Anynet to go between Optik/Apple etc with one remote I'm up to three, having to change the source as part of the routine. Total bollocks. Pretty sure I'm going to revert to my original setup