When Apple unveiled the iPhone 4S on October 4, Siri was seen as the new iDevice's biggest selling point and a major carrot to encourage iPhone 4 owners to upgrade. Although Siri originally appeared in the App Store in early 2010 before being acquired by Apple, the assumption was that the new version integrated into iOS 5 relied on the faster processor found in the iPhone 4S for Siri to work her voice recognition magic. Developer Steven Troughton-Smith and Grant Paul have proven that is not the case by not only getting Siri working on an iPhone 4, but also an iPod touch 4G.
Having previously succeeded in porting the Siri interface and some iPhone 4S code onto a jailbroken iPhone 4, Troughton-Smith and Paul have now managed to get the Siri port to communicate with Apple's servers to provide full Siri voice command functionality. The pair accomplished their feat by using software authentication tokens from a jailbroken iPhone 4S to trick Apple's servers into thinking an iPhone 4 and an iPod touch 4G were actually an iPhone 4S.
The only feature Troughton-Smith and Paul were unable to implement was the "raise to speak" feature that sees Siri activated when the phone is raised to your ear. This is apparently due to the fact that the feature relies on the new gyroscope found in the 4S.
In an interview with 9to5mac, Troughton-Smith says he has no plans to make Siri available for non-supported devices through the release of a specific jailbreak tool on Cydia or other jailbreak stores. While he admits others will likely do so, he is cautious of opening himself up to legal action by modifying and distributing files taken from an iPhone 4S. It won't stop him continuing his work, however, as he now plans to see whether he can make Siri run on an iPhone 3GS.
Whether this prompts Apple to make Siri available for devices other than the iPhone 4S remains to be seen. It can't make the argument that Siri requires the faster processor found in the 4S and Troughton-Smith and Paul aren't the only ones working on a way to get Siri onto unsupported devices.
In Apple's defense, Siri on the iPhone 4S is a beta release - sure, one that garnered a lot of attention and presumably played a part in the iPhone 4S being the company's most successful iPhone launch yet - but a beta release nonetheless. This means there's still a chance that Apple will bring some Siri love to owners of other devices once Siri has proven itself on the 4S. We'll just have to wait and see and hold our cynicism in check until then.
Here's video provided by Troughton-Smith to 9to5mac showing Siri working on an iPhone 4.