HOW TO: Fix FaceTime And No Cellular Data After Jailbreaking iOS 4.1

Now we got all the tools we need to jailbreak iOS 4.1. We have greenpois0n ( Mac, Windows and Linux ) , Limera1n ( Mac and Windows ) and PwnageTool ( Mac ). We also have redsn0w [Mac and Windows] for iPhone 3G and iPod Touch 2G running iOS 4.1. So everybody should be happy right? Well, that’s what we thought too, but it seems that a lot of you can’t activate FaceTime and get no cellular data connection.
As far as we can tell, this only happens if you use ultrasn0w to unlock your iPhones, but luckily, there’s an easy fix for it. So let’s get to it…


Before we begin, here’s what you need to know about FaceTime:
FaceTime is activated by sending a couple of SMS text messages in the background between the iPhone and an Apple server. If your carrier does not officially support the iPhone 4, you may be charged for sending the activation SMS to an international (UK) number. Your carrier might also have issues delivering the SMS correctly which will prevent FaceTime from activating. So make sure you can send and receive international messages.
FaceTime activation currently requires the iPhone to be activated, have an active SIM card with the ability to send and receive SMSes. If there’s an issue sending or receiving SMS messages, FaceTime can’t be enabled or activated.
Troubleshooting:
First thing you need to do is check if you got cellular data connection. If not, load Settings.app and see if the iPhone sees your correct carrier. Assuming that it does , go to Settings>General>About> and check the carrier . If you bought your iPhone from ( for example ) the US, chances are that, after unlocking your phone, it will not choose your carrier’s bundle, but the AT&T carrier bundle. Well, that’s your problem. ( See screenshot below for reference – just a random screenshot found with google images )

Fix:
1. Load Cydia and add the following source: cydia.pushfix.info
2. Install ‘Carrier Reset fix’
3. Eject the SIM after installation and re-insert it
4. Go to Settings>General>About> and now your iPhone should see the correct bundle
5. Enjoy your cellular data, and if FaceTime was ON and waiting for activation, you’ll probably receive a pop-up sayin ‘hey I’m about to send this international message’ . If not, go to Settings>Phone> and turn FaceTime ON. In a few seconds it will be activated.
NOTE: if by any chance , the FaceTime ON/OFF slider is not there, installing this patch will bring it back. If not, you might want to pop-in the original activation SIM ( i.e. AT&T SIM ), sync your iPhone with iTunes, and reboot it. Now the slider should be back on, and you can insert your own SIM.