Updating Firmware on Sharp 70" LC70C8470U
I saw the update notice for the "New Software Available" yesterday, Nov 1st/12.
What I did: Dismiss the notice and go to the Sharp's Site to download the New Firmware on my PC. I always keep an archival copy. I also read the information so that I know what will be changed or updated.
Next, I go to the TV and do a Manual Update via the Network. I have a Wired Network and my TV and all the Network devices are plugged into a UPS (Florida gets lots of Brown outs and Switching). The Update took approximately 10 mins to complete.
The TV rebooted itself and that was it.
I checked to make sure it really was updated. It was, with some new apps like Pandora, games, etc.
A slight power glitch may cause your update to behave strange. It is a good and safe thing to use a "UPS" to connect your TV and all Network components so that they do not get affected by these kinds of power fluctutations.
I hope it helps.