Performing the Jailbreak
Here are step-by-step instructions for jailbreaking iOS 5.1 (tethered) on the iPhone 4 with redsn0w on a Mac OS X Lion computer. The general procedure for performing any jailbreak is similar across jailbreaking applications, iDevices, and host operating systems. Thus, this representative example should be helpful to you regardless of your iDevice and computer setup. Let's rock and roll!
- Download, unpack, and start the latest version of redsn0w.
- In the initial redsn0w dialog box, click Jailbreak (see Figure 1).
- Read the instructions in the next screen carefully, as the steps vary a bit depending upon whether you have an A4 or an A5 device. Because I am jailbreaking an A4 iPhone, I will put my device into DFU mode (the procedure for which was explained earlier in this article). See Figure 2.
- Leave Install Cydia checked (this is the default option), and then click Next to instruct redsn0w to perform the jailbreak for you automatically (see Figure 3).
- The next screen reminds us that because this is a tethered jailbreak, we must connect our iDevice to our computer and run redsn0w again every time we want to reboot the device.
- To reboot your jailbroken iDevice, click Just Boot from the Extras interface in redsn0w. You'll need to put your iDevice into DFU mode, and the jailbreak boot process takes less than 30 seconds. Once your iDevice restarts, you can disconnect your iDevice and launch Cydia from one of your iDevice's app screens. See Figure 5.
- Locate Cydia on your jailbroken iDevice and launch the app. Cydia is the de facto software installer for jailbroken iDevices. We will get to know Cydia really well in the next installment of this article series.
Figure 1 Starting the iOS jailbreak
Figure 2 Preparing for jailbreak
Figure 3 Installing Cydia along with performing the jailbreak
Speaking of which, let's give that a try now in order to give you some practice. Click Cancel in the following dialog and reopen redsn0w.This time, instead of clicking Jailbreak on the initial redsn0w dialog, click Extras. See Figure 4.
Figure 4 The jailbreak is complete!
Figure 5 Performing a tethered boot on a jailbroken iDevice
For now, examine the very top and the very bottom of the Cydia home screen. The top of the interface lists your saved SHSH blobs. As you can see in Figure 6, I am missing a saved SHSH blob for iOS 5.0.1, which prevents me from undertaking an untethered jailbreak on this iPhone 4. Bummer!
Figure 6 The Cydia app home screen
At the bottom of the Cydia home screen we see listed the current version numbers of our iDevice, our iOS firmware, and Cydia itself.
Figure 7 Footer of the Cydia app home screen