I had an incident yesterday that is probably not the same as this thread, but symptoms were a bit similar, so I'm tacking it here rather than starting a new thread.
We were about half way through watching a 90 min SD recording from a previous day. There were two HD recordings currently running that had started about 20 mins before (it was about 2120). I noticed a moment of slight pixellation in the programme we were watching, which was unusual, but it passed. about 10 seconds later the picture and sound stopped and the 'unavailable/scrambled' scrambled message appeared. The box now appeared to be frozen - the play timer didn't advance and it wouldn't respond to the remote. After a couple of minutes I turned it off at the back for a few seconds and then back on. It restarted OK and I went to each of the channels that had been recording and started a manual recording for each. We then watched a different recording, not wanting to risk a repeat performance, and all was OK.
Today when there were no recordings running I went back into the 'faulty' programme and it was fine - no pixellation event, no freeze. This evening we watched it from about a minute before the crash point to the end and had no problems.
The box is a 1TB model, about 9 months old, has v29 firmware and a custom firmware (not sure but 2.14 I think), and the disc is about 20% full.
Should I be concerned? Is there a more elegant way out of this 'crash'? (eg. it's possible the recordings were continuing in the background, but powering off obviously killed them.)