I've looked at the instructions but I'm not at all clear in what I need to do. I do NOT want to risk losing my recordings...
It took me a couple of tries to get into maintenance mode but now all sorted and I still have my recordings.
I like that it also updated my Scheduled recordings information. In aerial mode I had a series recording set up for a programme on Channel 4 HD ( EPG #104). After a Maintenance mode 2 reset, the scheduled recordings information was updated to series record Channel 4 (EPG #4).