They were just banning the memory units that were not official. Knock-off HDDs are OK but if you want the "official" one then do not purchase them. If you got the dough then go genuine. If you're feeling cheap then buy a 120GB HDD from newegg and swap your 20GB out with it. There are tutorials on how to do this through google.
Happened to me around the evening time yesterday. Was watching my brother being a dick in Heavy Rain and then the game froze. Had to turn off the system manually and upon turning it back on I could not longer go online or play Heavy Rain again.. Have the ol' launch 60GB phatty.