I Declare Victory!
A few months ago I posted here that each morning I was waking up to my TiVo XL4 with a blank screen. I would have to unplug/plug several times to get it rebooted (It would hang between the Welcome Screen and the Few more Minutes Screen). It was suggested here that either my HDD was going bad, bad capacitors or there was software corruption. I then noticed that the TiVo would go down around 5:00am each morning. Apparently,the corruption caused the TiVo to try and reboot following TiVo downloading the "Teleworld" commercial.
I tried cloning my HDD via DVRBars, but unfortunately I had trouble doing this because as I learned later, I had a faulty external drive case. I hated to start out fresh with a new drive and image, losing all recordings and having to go through the headache of a new cablecard pairing. So I decided I would work around the problem by always having all four tuners of my XL4 recording from 3:00- 7:00am so that the Teleworld commercial couldn't come through. This worked like a charm for a couple of months- no issues.
Then came the summer update. I thought maybe the update would perhaps correct the corruption so after the update I stopped the four early morning recordings. It seems to have worked! It's now been a couple of weeks and everything is working well.
Note, I did finally do a DVRBars cloning to a backup drive last week so if anything goes wrong in the future, be it a disc going bad or software corruption, I'll have a ready solution.
Thanks to those who pointed me in the right direction for a solution.