Jailbreaking the iPhone has become difficult and we are seeing just how difficult as we wait for a jailbreak solution for iOS 6. In order to fully understand this, we must have a sense of what it used to be like and how it has changed.
When the iPhone 3G launched, a jailbreak tool called Pwnage Tool was released. It was based on a bootrom explooit that allow the iPhone's hackers to change the software on the device. This is powerful access in terms of jailbreaking the iPhone. When the iPhone 3GS was released, the key bug that allowed developers to have this level of access was still present. Apple then shut down the manufacturing cycle of the iPhone 3GS and addressed this problem. When they started production again, the bug was gone and there was a new bootrom in place.
Jay Freeman who created the well known jailbreak app store, Cydia, says that Apple's motivation was to fix the bug but why they chose to fix this bug instead of others is still unknown. This didn't prevent hackers from looking for other ways to access the iPhone's code. After Apple fixed the one bootrom bug, jailbreakers were able to discover other bootrom bugs but there were only able to change the software on a temporary basis. This allowed iPhone users to run jailbreak apps and modify how the iPhone behaved but as soon as the iPhone had to be rebooted the jailbreak was lost unless it was rebooted connected to a PC. This is known as a tethered jailbreak.
Apple continued to improve their iOS and by the time the iPhone was released, jailbreakers had to find a bug in a program running on the iPhone that they could use to access a bug in the kernel. @comex was the one to discover this and he launched the JailbreakMe website. He was later hired by Apple.
The next big step in jailbreaking was to make the jailbreak untethered meaning that the iPhone could boot up directly to the jailbreak. This was also achieved but every time a new iPhone was released, the search for new bugs began. When the iPhone 4 was released a new hacker called Geohot discovered the Limera1n exploit and other hackers then began working on untethers for this jailbreak. The Limera1n exploit is important because it is a bootrom exploit and it lasts for the life of the device. Limera1n is in every device that shipped with that bug and the only way for Apple to get rid of it is to stop production like they did with the iPhone 3GS to fix the bug.
When the iPhone 4S was released Limera1n was gone and again the hackers had to go back to looking for exploits. When these were identified and used to develop a jailbreak they were then patched by Apple in the next firmware upgrade. Corona was the exploit used for a jailbreak for the iPhone 4S running iOS 5.0 and 5.0.1 but when Apple released iOS 5.1 the bug was gone. Absinthe was the jailbreak for iOS 5.1 and 5.1.1. Once Apple released iOS 6 the bugs were gone again.
The iPhone 5 and iOS 6 has significant security improvements as those iOS 6.1. This is why we are still waiting for a jailbreak. The hackers are still looking for bugs and it is proving to be tough.
Some people wonder if jailbreaking is over especially when you consider that Apple have addressed a lot of things jailbreakers were looking for. We can even buy unlocked iPhones. It doesn't seem to be the case though and people are still anxiously waiting for the next jailbreak to arrive.
