A new PlayStation 3 firmware update is now available to download using the [System Update] feature. This optional update improves system stability during the use of some PlayStation 3 titles, including the Uncharted: Drake’s Fortune freezing issues. It’s taken Sony two weeks to release a patch for the reported issues, but at least it’s finally here.
If you have been experiencing freezing issues with Uncharted or any other title, you are recommended to update to version 3.01, otherwise, you should keep firmware 3.00 installed. This update is optional so you are still able to access the PlayStation Network if you are on firmware 3.00.
Source: xtremeps3
