As previously reported, those with converted PS3 consoles should hold off installing this update as it will brick your system.
From the included Readme_DECH-441_001_e.txt file:
Contents of This Package
Changes in Release 441.001
<System Software (GUI)>
- The update data for debugging station has been updated at the same timing as the release of the system software 4.41.
This update does not affect titles....
23w ago - Following up on their previous update, today Sony has officially released PS3 System Software Update 4.46 which now fixes the widespread 4.45 PS3 bricked consoles (for some) and also allows users to turn off trophy notifications.
24w ago - Following up on their previous updates, today PlayStation 3 scene release group Duplex has made available some more PSN games including Dungeons and Dragons Chronicles of Mystara PSN PS3, Giana Sisters Twisted Dreams PSN PS3 and Thunder Wolves PSN PS3 with details below.
24w ago - Following up on PS3 Firmware 4.41, today Sony has released PS3 System Software update 4.45 followed by reports of mass-bricking (with PSN temporarily closed via Error 8002A308) so currently it is advised NOT to install it.
Beware as it is causing a lot of consoles (mine included) to brick! There seems to be a glitch (pictured below) with a lot of users updating to that firmware and getting freezes after restarting. For those curious, the new update is supposed to allow users to 'opt-out' of the pop-up messages that you earned a trophy while playing a game.
Some reports indicate that this primarily affects those with 500+ GB hard drives, however, it is advised not to update to 4.45 until Sony remedies the issue. Currently they have rolled back to Firmware 4.41 meaning when you boot up your PS3 you will no longer be prompted to download the 4.45 update.
From Sony's Twitter on the PS3 Firmware 4.45 changes: "PS3 system software update 4.45 coming soon,...