Official firmware 5.02 for PSP

Original Version 5.02(download)

An update to the PSP system software was released on November 20, 2008. If you update your PSP system, the system software version will be 5.02 and the following features will be updated.
This minor update is now available on a worldwide basis and as usual, can be obtained from Network Update. As detailed earlier, not a whole lot has changed, with the changelog mentioning that PlayStation Store stability has increased.

*Note: if you update to version 5.02 ofw, maybe you cannot play game from your memstick.
So, think it before.*