How to Patch & Install Cydia on iOS 4.2.1 After Redsn0w Jailbreak [Guide]

The recently released Redsn0w 0.9.6b3 can jailbreak all iOS based devices including the new A4 devices like iPhone 4, iPad and iPod touch 4G. Since Cydia included in this version of Redsn0w is not compatible with iOS 4.2.1, you can use the following steps to install a patched version of Cydia.

Step 1: First up, you will have to jailbreak your device using the newly released Redsn0w.

Step 2: Next, you will have to enable SSH by installing the compiled OpenSSH bundle using Redsn0w,

Step 3: Now simply download Cydia.patch file for iOS 4.2.1 from here and copy it to/Applications/Cydia.app/Cydia_ directory by SSH’ing into your iOS device. Windows users can use WinSCP while Mac users can use Cyberduck. Login instructions for SSH can be found below.

Cyberduck

• Server: The IP address of your iPad. Settings –> WiFi –> <Your Network Name>
• Username: root
• Password: alpine
• Protocol: SFTP (SSH File Transfer Protocol)

WinSCP

• Hostname: The IP address of your iPad. Setting –> WiFi –> <Your Network Name>
• User name: root
• Password: alpine
• Protocol: SCP

Step 4: Now start Terminal app on Mac OS X and by using the original Cydia binary type the following commands in Terminal app on Mac OS X:

ssh root@<ip-address-ios-device>

Now login as root by entering “alpine” as password.

Once you have logged in:

apt-get update
apt-get install bsdiff
cd/Applications/Cydia.app/
cp Cydia_ Cydia.bak
bspatch Cydia.bak Cydia_ Cydia.patch
chmod +x+s Cydia_

Step 5: Now from here onwards, whenever you want to use Cydia or SSH into your device, you must first run your device in the so called “jailbroken state” on every reboot by using “Just boot tethered right now” option in Redsn0w.

NOTE: All iPhone unlockers must STAY AWAY from Redsn0w. Redsn0w 0.9.6b3 supports tethered jailbreak only.

That’s it! Enjoy Cydia on your jailbroken (semi-untethered) iOS 4.2.1 device !