iOS Jailbreaking 101 Part 2: Ensuring Your Device's (and Your Data's) Safety
- What Do You Stand to Lose if Jailbreaking Fails?
- Obtaining the Necessary Software
- Backing Up Your iDevice
- Backing Up Your SHSH Blob(s)
- Next Steps
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Welcome to the second installment of our four-part trolley ride through the wild and wooly world of iOS jailbreaking.
You've probably heard the old adage, "You must learn to crawl before you learn how to walk." For our purposes today, this adage can be applied inasmuch as we need to know how to back up our iDevice's user data before we can discuss jailbreaking our devices.
I structured this article to answer the following essential pre-jailbreak questions:
- What do I stand to lose in case jailbreaking fails?
- What hardware and software is required for me to jailbreak my iOS device?
- How do I back up my iDevice's user data?
- What is an SHSH blob and why do I care?
Are you ready? Let's do this!
What Do You Stand to Lose if Jailbreaking Fails?
In my years of experience with hacking Apple hardware, I have never once bricked (that is, rendered permanently unusable) an Apple portable device through iOS jailbreaking. Moreover, I have yet to meet a fellow jailbreaker who has done so.
By contrast, I certainly know people who have lost their user data during or after an iDevice jailbreak. The explanation for this unfortunate situation is simple: The users in question failed to follow basic safety precautions before undertaking the jailbreak.
The bottom line here is that you need to have the following data safely backed up before you perform a jailbreak or any other type of iDevice hacking:
- iDevice system state and user data
- SHSH blob
We will cover what SHSH blobs are and why they are important later in this article. For now, let's understand what "system state and user data" actually are. To wit, a quick tour of the Apple Support Communities forums reveals a large amount of user ignorance with respect to the difference between an iDevice synchronization and a backup.
By default, iTunes performs both a backup and a sync whenever you plug your iDevice into your Mac or Windows computer by using its included USB cable. These processes take place in the following order:
- Backup makes a copy of preferences and metadata and stores it in the iTunes backup library.
- Synchronization transfers user data between the iDevice to the host computer to ensure that both systems have a copy of the same data.
Because user-created content is irreplaceable, we must take pains to protect it with the highest priority. According to the Apple Support Web site, an iTunes backup stores the following user data from a connected iDevice:
- Photos and video from the Camera Roll
- Device settings (Phone favorites, wallpaper, Mail, Contacts, and Calendar account metadata)
- App preferences (not the apps themselves)
- Home screen and app organization
- Messages (iMessage, SMS, and MMS)
- Ringtones
- Passwords for Wi-Fi and Mail accounts
In perusing the previous list, you may think, "Well yeah, the iTunes backup stores a lot of metadata or data describing my data. However, where are the rest of my photos from my photo library? Where are my e-mail messages? Where are my apps?"
The answers to these questions lie in the synchronization process. Whereas the iTunes backup process stores (for the most part) metadata, the synchronization process transfers file assets between your iDevice and your host computer for storage in the iTunes library.
The desktop applications that work in conjunction iTunes and your iDevice to sync your data vary depending upon your operating system. Table 1 summarizes the most commonly synced desktop applications in Windows and Mac OS X.
Table 1: Mac and Windows Sync Apps
| User-Created Assets |
Windows Sync Apps |
Mac OS X Sync Apps |
|
Contacts |
Microsoft Outlook/Windows Live Mail |
Apple Address Book/Microsoft Outlook for Mac 2011 |
|
Calendar appointments |
Microsoft Outlook/Windows Live Mail |
Apple iCal/Microsoft Outlook for Mac 2011 |
|
E-mail messages |
Microsoft Outlook/Windows Live Mail |
Apple Mail/Microsoft Outlook for Mac 2011 |
|
Photos |
Windows Live Photo Gallery/Adobe Photoshop Elements |
Apple iPhoto |
|
Music |
Apple iTunes |
Apple iTunes |
|
Movies |
Apple iTunes |
Apple iTunes |
|
Ringtones |
Apple iTunes |
Apple iTunes |
You will learn how to perform iDevice backups and synchronizations manually a bit later on in this article.