Ok so this is a little nifty thing that i found using SAM provided by http://repo.bingner.com/ I'm new to this community, you dont have to trust me, and nothing that happens from this is my fault except the cure for cancer. Please give it a go, this is specifically for iphones and you should be already to get around the setup screen to access cydia.

1. Jailbreak you device first using This awesome tutorial

2. Grab a file explorer off of cydia, probably iFile

3. On iFile go to "service/library/coreservices/systemversion.plist

4. Open the plist in an editor (in property list editor)

5. delete the release type key (it only says beta in there if your wondering)

6. To activate the phone go to cydia and add the source "http://repo.bingner.com/"

7. Download the package SAMpref

8. Open up SAM and go to utilities and restore activation

9. Tether reboot it

10. This time when you go through the setup, you should be able to go through all of it

Please send feedback (JKshowman@gmail.com) and see if it works, cause i don't see why not