The crackers are currently working on the software required to perform that task, according to postings on the PSP3d website.
Current models of the PSP ship with firmware version 2.5, but some users prefer to run the older version 1.5 because this allows them to run the home-brew applications.
Such applications allow users to add functionalities to the portable device, letting it display text files, for instance, or play streaming music from the internet.
Starting with version 2.0 of the firmware, Sony has blocked users from installing custom applications. The move set off a game of cat and mouse where crackers hacked the software and downgraded it to the 1.5 version.
When Sony upgraded to version 2.5, it once again blocked the hack that was used to downgrade the application. Sony could not confirm the latest crack described on the PSP3d website.