How to fix Different SIM Detected Error on iPhone 3G/3GS/4 after Activation with Phonebook SIM

A new hacktivation patch has been released by Sherif Hashim which lets users jailbreak their phone with JailbreakMe and use Phonebook SIM to activate. All you need to do is install a package from Cydia while using your phonebook SIM card and then swap it with your carrier SIM card.

From Cydia:

This package allows you to swap SIMs after activation with a phonebook SIM. You won’t get the SIM change detected error. Hacktivation will patch a system file on your phone, preventing future activation and keeping your current activation even if you change your SIM.

Here are the steps in detail:

1. Insert your Phonebook SIM card.
2. Start Cydia and go to Manage tab.
3. Go to Sources, and tap Edit on the top. Tap on add.
4. Add this source: http://cydia.pushfix.info
5. When Cydia is done reloading the repos, type Hacktivation Patch in search and install it.
6. Remove phonebook SIM card and insert your carrier SIM.