Install AppSync 4.2 for iOS 4.2.1 from Cydia – How to Guide

By | November 24th, 2010

The Appsync 4.2 is now available from Cydia to download that is compatible with iPad, iPhone and iPod Touch running firmware 4.2.1. The update will patch the MobileSubstrate installion allowing you to manually install .ipa files directly from your computer. AppSync requires a jailbroken device.

If you haven’t already, you can jailbreak your device running iOS 4.2.1 by following this guide. It is advised to go through the whole procedure before starting.


  • Launch the Cydia app from your iPad or iPhone.
  • Go to the Manage tab and select Sources.

  • Now tap on Edit and Add to enter the URL: and touch Add Source. Let Cydia update your sources database.

  • Now go to Search tab and look for appsync for OS 4.2. Select this app by tapping onĀ Install and then confirm. It will perform a series of steps to get the application installed. You should be able to install .ipa files by using iTunes directly from your computer.

If it doesn’t work, restart the device and repeat the procedure.