I got online last night and downloaded the Store update. Download went fine. I started about a 2 hour session on Black Ops II when the game froze. I ejected the disc and it was VERY hot, as was the system. I tried other games, and they froze as well. Some online, some not.
Left system off overnight to cool down and tried this morning - no problem. I haven't had time to try another 2-3 hour session, but I am afraid it is going to get hot again and lock up.
I just find the timing very curious. I had an issue with a system update once where after the update, I couldn't get games to load unless I put the system sideways. Another update comes and the problem went away without a word from Sony.
I don't expect Sony to admit to a problem due to liability concerns. Just putting my experience out there to see if anyone has seen something similar.