PlayStation 3 firmware 2.4 bricked a few systems, was eventually pulled and then, today, got rereleased as firmware 2.41. Hooray!! But wait a second...what exactly went wrong with 2.4 in the first place? Sony has gone on the record with an official explanation:
The PLAYSTATION®3 (PS3™) system software version 2.41 is now available for update from July 8, 2008. With this update, we have fixed the problem that prevented a limited number of PS3s from activating properly after updating to version 2.40, when certain system administrative data were contained on the HDD...
...We apologise for any inconvenience this may have caused you and appreciate your understanding and continued support.
Damn that system administrative data! It gets us every time. [ThreeSpeech]