Reports are coming in from PS3 users who have already downloaded the new 4.45 patch that just arrived, that it is locking up their consoles. The incident probably won’t happen to everyone, but it may be a safe bet to wait until Sony corrects this issue before downloading the new firmware. Offline play until then may suck, but it sounds much better than a bricked console. This problem should hopefully be corrected with the release of 4.46 update.
The firmware will be adding new trophy notification and improved system stability.
[Sources:PlayStation.com and kotaku.com]