Jailbreaking is the process of removing the limitations imposed by Apple on devices running the iOS operating system. Tethered jailbreaking requires users to reconnect (tether) to their computer every time the device is restarted while an untethered jailbreak is a one-time activity and is free of this restriction. Both tethered and untethered jailbreaks give users the ability to install “unauthorized” software on iPhones, iPads and iPods, i.e. applications that are not downloaded from Apple's app store and have not been approved or vetted by Apple. These include apps from the Cydia app store.
With every new version of iOS, Apple makes it more difficult to jailbreak and there is usually a lag before jailbreak software catches up to the latest iOS version. Software for tethered jailbreaks is released first because untethered jailbreaking is more difficult. Jailbreak software may be different for each iOS device type (iPhone, iPad and iPod).
edit What is a tethered jailbreak?
A tethered jailbreak implies that every time your idevice (iPhone or iPod touch) reboots — for example, if the battery dies — users have to connect (tether) the iOS device back to a computer running the jailbreak application, which lets the iPhone or iPad boot up and stay jailbroken.
edit What is an untethered jailbreak?
An untethered jailbreak requires no connection to your computer to restart the iOS device. You can reboot your iPhone or iPod Touch normally, just as you would do for a device that has not been jailbroken.
edit Jailbreak Software
There is a lot of malware on the Internet promising to jailbreak iPhones and iPads. Some of this software costs $10 to $30 but most of it is available free. Malware distributors not only have websites hawking their wares, they also use YouTube videos that show supposedly jailbroken phones. However, users should exercise great care before downloading any jailbreak software.
edit How to Jailbreak an iPhone or other iOS Device
edit iOS 6.1 untethered jailbreak
- Preparatory steps:
- Passcode lock on the device will need to be disabled.
- Have the USB cable handy to connect the iDevice to the computer.
- Back up the iOS device using iTunes so that if something goes wrong, you can recover from backup.
- If you are running an older version of iOS, please see some additional preparator steps.
- Download the jailbreak software from the evasi0n website for Windows, Mac and Linux.
- Connect the iOS device with the computer. If iTunes opens up automatically, close iTunes. Also make sure Xcode is closed if you have that app running on your Mac.
- Run the jailbreak software. Do not use your device during the jailbreak.
- If the process gets stuck, it is perfectly safe to restart the program, reboot the device (if necessary by holding down Power and Home until it shuts down), and rerun the entire process.
The iOS 6.0 and 6.1 jailbreak process takes about 5 minutes.
Jailbreaking voids the warranty on Apple products. Apple Support will refuse to help users who have jailbroken their devices - by phone or on the support forums.
Another risk is malware. Many purported jailbreaking tools are merely malware in disguise that can infect your computer. Moreoever, jailbreak lets users install apps that are not vetted by Apple and some of these could be malware that could infect your iPhone or iPad.
Tethered Jailbreaking: QuickPwn, purplera1n, blackra1n, and sn0wbreeze 2.0, can jailbreak iOS 4.1 on devices older than iPhone 4 and iPod Touch 4G.
For Untethered Jailbreaking for iOS 4.1 and older versions, greenpois0n, PwnageTool, limera1n, and sn0wbreeze, Absinthe can be used.
- In October 2007, JailbreakMe 1.0 (also called "AppSnapp") allowed people to jailbreak iPhone OS 1.1.1 on both the iPhone and iPod Touch, and it included Installer.app as a way to get software for the jailbroken device. Comex released JailbreakMe 3.0, a web-based tool for jailbreaking all devices on certain versions of iOS 4.3, including the iPad 2 for the first time (on iOS 4.3.3)
- iphone Dev Team released a version of PwnageTool in July 2008 to jailbreak the new iPhone 3G on iOS 2.0 as well as the iPod touch, including Cydia as the primary third-party installer for jailbroken software. They keep updating it.
- They released QuickPWN to jailbreak iOS 2.2 on iPhone and iPod touch, which also enabled certain functions disabled by Apple.
- After Apple released iOS 3.0, the Dev Team published redsn0w usable on Mac and Windows, and they keep updating it.
- Chronic Dev Team initially released greenpois0n in October 2010, a desktop-based tool for jailbreaking iOS 4.1and later iOS 4.2.1 on most devices including the Apple TV, as well as iOS 4.2.6 on CDMA (Verizon) iPhones
- The iPhone Dev Team, Chronic Dev Team, and pod2g collaborated to release Absinthe in January 2012, a desktop-based tool to jailbreak the iPhone 4S for the first time and the iPad 2 for the second time, on iOS 5.0.1 for both devices and also iOS 5.0 for iPhone 4S.
- An update on several tethered and untethered jailbreaks for iOS 6. As of this writing, iOS jailbreak had been achieved for iPhone 4, iPhone 3GS and iPod Touch, and a tethered jailbreak for the iPhone 5 had also been achieved, but required the user to have a $99 per year iOS developer account.