How To Install Cydia On iOS 4.2.1


With the newly released version of Redsn0w able to jalbreak iOS 4.2 you still can’t get cydia on there because its for devs only. Redmondpie has posted a great how to on patching cydia to work with the new firmware. It’s a bit complicated and requires you to reboot your device to be able to use cydia but its better than nothing.

How to install and patch cydia iOS 4.2.1:

Step 1: First up, you will have to jailbreak your device using the newly released Redsn0w by following the instructions posted here.

Step 2: Next, you will have to enable SSH by installing the compiled OpenSSH bundle using Redsn0w, instructions for which can be found here.

Step 3: Now simply download Cydia.patch file for iOS 4.2.1 from here and copy it to /Applications/ 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.


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


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

Enable Tethering on iPhone 3.1.2 Firmware [iPhone 3GS and iPhone 3G]

Patch Cydia on iOS 4.2.1

Step 4: Now start Terminal app on Mac OS X and by using the original Cydia binary from here, 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


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.

Redsn0w (1)

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 !


  • quappe.

    i thought ios4.2 has wlan problems yet. how to ssh the device if i have wlan problems?

  • quappe.

    can i tunnel ssh thorugh cable connection too?

  • Hass

    I hope a better jailbreak would cum up soon cuz am not using that one lol