NOTE: As always, before we get started, there are a few things to keep in mind here. This jailbreak guide is for users who are on iOS 6.1.2, this jailbreak support all Apple devices so don't worry and it is Untethered.
Be sure that your device’s passcode lock is disabled. The passcode lock can interfere with the jailbreak process. Also, make sure that when you upgraded to iOS 6.1.2, it was done, not via an OTA update, but via an iTunes update. While it’s possible that it will work, OTA updates have caused known problems in the past with regard to jailbreaks, it’s best to just play it safe. Okay, let’s get started!
STEP 1: Head over to our download page, and download evasi0n 1.4. The downloads are available for Mac, Windows, or Linux.
STEP 2: Save the evasi0n app to your desktop, and run it.
STEP 3: Connect your iOS device to evasi0n, and ensure that evasi0n detects your device. Evasi0n should work with any iOS 6 firmware from iOS 6.0 to iOS 6.1.2. In this case, you will be using iOS 6.1.2.
STEP 4: Click the jailbreak button, and the jailbreak process will begin. Be patient, as this takes a while. You will notice your device reboot several times throughout the entire process. The main thing is just to be patient.
STEP 5: Eventually, evasi0n will ask you to unlock your device, and tap the Jailbreak icon on your Home screen once. Follow these instructions, ensuring that you tap the icon only one time, and then leave the device alone and let it continue.
STEP 6: The evasi0n app will complete its course, and you will be able to click the Exit button. The iOS device, however, still needs to finish up a few additional steps, so again, be patient and don’t touch your device.
STEP 7: Eventually, the jailbreak will finish, and you can unlock your iOS device, and open the Cydia app on your Home screen. Cydia will need to initialize, which takes about 1 to 2 minutes. After the initialization is complete, the device will respring again.
STEP 8: Reopen Cydia, select Hacker, and begin enjoying your newly jailbroken iOS device running iOS 6.1.2.
Congratulations you've just jailbroken your iPhone running on iOS 6.1.2