By now we know, the Redsn0w 0.9.6b4 release can be used to jailbreak iOS 4.2.1. Now, jailbreakers are looking for a way to install cracked iPhone apps and games (.ipa). Enters AppSync, an app that patches the MobileInstallation file on iPhone, iPad and iPod Touch, and makes it possible to manually install cracked apps.

Pre-requisite: If you want to install Appsync, ensure you have jailbroken your iPhone, iPad or iPod Touch running iOS 4.2/4.2.1 update.

Below is a step-by-step guide to install AppSync on iOS 4.2.1:

1. Launch Cydia App from your iPhone Springboard.
2. Go to: Cydia > Manage > Sources > Edit > Add
3. You will be asked to enter a URL source. Key in ‘http://cydia.hackulo.us’ and click on ‘Add Source’.
4. Soon the Hackulous repository will get added.
5. Upon complete installation, tap the Search tab of Cydia, search for ‘Appsync’ and install the ‘AppSync for OS 4.2′ app.

All you need to do is reboot the device to be able to install .ipa files to it. You just need to connect your device to a PC and run iTunes to be able to install .ipa files.

Disclaimer: TechHail does not support piracy in anyway. This guide is for informational purposes only.