One of the features that didn’t make it to iOS 5 was the ability to make FaceTime – Apple’s video calling feature over 3G.
However, it is possible to enable it on iPhone 4 by hacking one of the system files.
Here are the step by step instructions to enable the feature natively on your jailbroken iPhone 4:
Step 1: Download iFile for iPhone from Cydia or iExplorer for Mac and Windows
Step 2: Browse to /System/Library/CoreServices/SpringBoard.app/
Step 3: Open the file named N90AP.plist (please take a backup of your iPhone before making any changes so you can restore it from the backup if you hit any issue)
Step 4: Below the <dict> line, under <key>capabilities</key>, add in <key>3Gvenice</key><true/>
Step 5: Save the changes.
If you’ve jailbroken your iOS device then jailbreak apps like My3G that allow you to make FaceTime calls over 3G.
That’s it, you should now be able to make FaceTime calls over 3G.
As always, let us know how it goes.