Numerous reports are indicating that the latest PS3 firmware release, version 4.45, may be bricking certain consoles. Sony have confirmed they are aware of the problem, and have temporarily taken version 4.45 offline until a fixed version can be produced.
Affected PS3s will not display the XMB when the update is applied, and so far, no workarounds or fixes to the problem is apparent.
It is also unknown which PS3 models are affected, although users report that 500GB PS3s are among those that are suffering from the bug.
In an official statement posted on the PlayStation boards, SCEA PSN Community Management Team Morgan Haro asked for patience while Sony examined the cause of the problem, and come up with fixes.
"We are aware of reports that the recent PlayStation 3 system software update (version 4.45) has caused the XMB to not display on a small number of PS3 systems. We have temporarily taken 4.45 offline and are investigating the cause of the problem. We will announce when the system update is available for download as soon as possible. We apologize for the inconvenience," posted Haro.
Those that haven't updated to 4.45 should no longer be prompted to update, but if a prompt does come up, it is strongly recommended that you to skip this potential problematic update for the time being.
Update: "A new system software update is planned to be released on June 27 that resolves the issue," according to new statement from Sony.