AppSync, the app used to install .ip files manually, has been updated to a newer version for the iOS 4.2.1 firmware running devices. All those who have been able to jailbreak their devices and obtain cydia on their iPhone or iPod Touch or iPad on iOS 4.2.1 can install AppSync 4.2. Here are the instructions to install AppSync 4.2 on iOS 4.2.1.

NOTE : We don’t have any intention to promote piracy with this hack. This should be used only for informational purposes.

1. Jailbreak your iPhone or iPod Touch or iPad on iOS 4.2.1.

Jailbreak iOS 4.2.1 on Windows and Mac OS X

2. Launch Cydia.

3. Select the ” Manage ” tab.

4. Tap on ” Sources “.

5. Add the source ” http://cydia.hackulo.us “.

6. When the source is added, search for ” AppSync for OS 4.2.1 ” in Cydia.

Install AppSync 4.2 on iOS 4.2.1

7. Install the AppSync for iOS 4.2.1.

That’s it! You have successfully installed AppSync on iOS 4.2.1.