There are plenty of cases of firmware updates killing blu ray drives, freezing systems, game glitches etc.
One chap even filed a law suit against sony for Version 3.0 killing his blu ray drive (only in the US!)

Pretty much since version 3.0 was released last year, there have been more and more complaints.

http://news.vgchartz.com/news.php?id=7694

http://boardsus.playstation.com/t5/P...2/m-p/44421509

http://gizmodo.com/5449974/is-a-firm...blu+ray-drives

http://www.gamesindustry.biz/article...are-3-0-issues

http://www.destructoid.com/sony-look...s-147754.phtml

http://blog.us.playstation.com/2009/...firmware-3-00/