Apple disabled Siri on non-4S devices.
If you’re having trouble using Siri on an iPhone 4 or iPod Touch 4G try this:
1.Turn Siri off
2.Delete the Plist file. Using iFile/SSH from Cydia browse to /var/mobile/Library/Preferences and delete com.apple.assistant.plist
3.Delete any profile (certificates) you have for Siri in settings
4.Download the certificates again from wherever you obtained them
5.Re-enter the server address in spire. [You must use https:// (i.e. https://123.456.789.101%5D
6.Re-enable Siri
7.Try Siri
How to video (English):
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Hope this helps you! Leave us your questions and comments.
EPELTECH 