Crackers claim to have found a new vulnerability in the software running Sony's Playstation Portable (PSP) that could allow them to run so-called home-brew applications on the device.

A user by the name of 'butterballer360' posted a description of the hack, as well as files that help users perform it, on the PSP3d.com enthusiast website. 

The vulnerability will allow users to modify the portable gaming device to allow the installation of a different version of the firmware.

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.

"The demand and excitement for PSP has been very strong, and in turn consumers have already found many uses for PSP," a spokesman for Sony's gaming division told vnunet.com. 

"However, PSP contains robust technology and was designed to run specific applications via the Universal Media Disc or memory card.

"Consumers should be aware that any hacking or home-brew applications may cause damage to the PSP unit and may void the warranty."

Programming vandals have already tried to capitalise on the urge to crack the application. Several Trojans are floating around online that promise to change the firmware but in reality render the device unbootable.