iPhone-Dev Team member MuscleNerd has tweeted that Apple is fixing their activation servers which means that users will be unable to unlock your using SAM (Subscriber Artificial Module) method.
Looks like Apple’s currently fixing their activation servers. But the good news is that previous tickets gotten via SAM trick still work.
The activation tickets for those who have unlocked their iPhone with SAM still works.
It is advisable that users should Unlock iPhone using SAM and then back-up activation ticket using the latest version of Redsn0w.
How To Backup iPhone Activation Ticket Using SAM Method
1. Launch Cydia on jailbroken iPhone.
2. Add repo.bingner.com and install SAM.
3. Open SAM >> Utilities >> Deactivate.
4. Open Main Menu of SAM and tap on More Information. Now ,under SIM Details copy your IMSI number.
5. In this step remove your SIM and replace the SIM with the SIM which you want to use.
6. Keep SAM enabled, tap Method and then select By Country and Carrier.Go back a menu, and select correct country and then the correct carrier for the SIM card.
7. Now go back to More Information >> tap Spoof Real SIM to SAM.Under SAM Details, delete the current IMSI number and replace it with the IMSI number which you copied in step 4.
8. Go to SAM main menu >> go to Utilities >> tap Attempt Activation.Your iPhone will respring now.
9. Open SAM and disable and Close it.
10. Open iTunes and plug in iPhone to your computer, unplug and plug it again in few minutes.A message will appear that it failed to activate your device.Soon you will find a carrier logo for your new SIM.
You can refer to the following video by Jeff Benjamin:
Until Apple starts fixing Activation Servers, you should save Activation Severs for iPhone Unlock.