Steven Troughton-Smith, the developer behind many popular iOS apps and tweaks, has been busy at work porting the (formerly) 4S-exclusive Siri to the iPhone 4. We assume that Apple made Siri unique to the 4S to entice users to upgrade or to restrict the beta software to a limited number of users, because according to Smith, Siri works just as quickly on last-gen hardware.
Currently, Siri can only run on the iPhone 4 in software GL mode with the GPU disabled, so the port is far from finished. But, considering that the hacker has made this much progress without actually having a 4S in hand to work with, we’re very impressed. It shouldn’t be too long before Siri is available on all iOS 5 devices.