It appears that a hacker from Amsterdam by the name of Kaatje
, has managed to create a custom firmware that allows iPhone 3GS users to jailbreak the newest iPhone OS 4.0 Beta 4.
The iPhone Dev team
released Redsn0w 0.9.5 to jailbreak iPhone OS 4.0 Beta 4, however it was only compatible with the iPhone 3G. With Kaatje's work, we now have reports of a jailbroken 3GS running 4.0 Beta 4. And to top it off,