actually, something funky is happening with my receiver and the NBR. see this thread for more info. I too have the 4.03 update. This just started about 4 days ago.
I received the 4.05 update a couple of days ago for the 508. The update didn't immediately erase any of my recording like previous versions randomly would do. Unfortunately, last night, all of my recordings were erased (viewed or not viewed; protected or not protected). I will be watching to see if this continues.