A quiet update to the PlayStation 3's system software has stopped the recent PSjailbreak piracy hack from functioning.

Speaking to our sister site Eurogamer, Digital Foundry's Richard Leadbetter explained that the discreetly-released 3.42 update, which will be required to access the PlayStation Network service as of today, will actively prevent the security bypass known as PSjailbreak working.

However, it may be possible for hackers to reverse engineer the download to re-enable the hack. Offline machines will not be affected.

"Yes, people have tried it and the Jailbreak no longer works," Leadbetter told Eurogamer.

"3.42 is the only way to access PSN, so in Sony's world you have to upgrade. However, for now it looks like people who have the Jailbreak are sticking to 3.41 and using a proxy server bypass to remain online.

"Going forward, the hackers will be attempting to reverse engineer future firmwares and producing custom versions that keep the exploit working."

Sony recently won a case in Australia to have the PSjailbreak kit removed from online retail stores, as well as forcing a blanket ban on sales and imports of the device in the country.

Sony is also making inroads into having the device ruled as illegal in the United States.

The homebrew alternative to PSJailbreak, known as PSgroove wasn't covered by the legal rulings, but has also been affected by the firmware update.