Siri has been ported to older iOS devices, including iPhone 4 and 3GS by well known hacker chpwn and stroughtonsmith. However, the ported Siri cannot yet connect to Apple server and receive responses.
Here is a step by step guide to port Siri on iPhone 4, iPhone 3GS or iPad on iOS 5 or iOS 5.0.1
- Jailbreak your iPhone 4 or 3GS
- Install iPhone Explorer or any other software to transfer files to your iPhone or iPad
- Open Cydia and install iFile
- Download this file: http://www.mediafire.com/?c2xnfqfvsh1vgk7
- Extract archive downloaded above.
Copy the folder AssistantServices.framework to /System/Library/PrivateFrameworks/ on your iDevice
- Copy all the files inside Springboard folder to /System/Library/CoreServices/Springboard.app
- Launch iFile on your iDevice and navigate to /System/Library/CoreServices/Springboard.app. Open file N81AP.plist for iPod touch 4G and N9x for iPhone 4 (where x may be 0, 1, 2).
- Reboot your iDevice and Enjoy Siri on your iPhone or iPad. Remember that it is only GUI and not fully functional SIRI port