Sunday, October 28, 2012

Jailbreak for Dummies: Types of Jailbreak


What?! There's different types of jailbreaks?

Yes. Jailbreaks ultimately gives you root access and Cydia, but each jailbreak is different. 

A little backstory...
Since the day iPhones walked the earth, jailbreaks have been attempted. Apple doesn't like this, and tried to make jailbreaking illegal, but court rulings allowed jailbreaking. Previously all devices are allowed to be jailbroken, but the latest court ruling decided that tablets (iPads) cannot be jailbroken anymore. It's a good thing I don't own one then. 

Using the analogy of fencing up the iOS in the previous post, each time a hacker use the holes he found in the fence to enter iOS and release a public jailbreak, Apple patches the holes. The holes here are 'security vulnerabilities', weak spots in the fence that can be exploited to do more than just jailbreaking, if the hacker has ill-intentions. Therefore it's important that Apple patches these holes quickly, usually in the next iOS update.

As a result, each new jailbreak generally uses different holes in the fence, and each update patches the holes that Apple knows about. This is basically a cat and mouse game that goes on and on.

Untethered Jailbreaks
I'll start my description by explaining the 'magic' (again, see the previous post) that hackers do. Think of spies in the movies. They infiltrate some organization, place some tech gadgets around, and suddenly they can monitor and control everything, shutting doors and turning on self destruct to kill the hero of the film, which incidentally is very likely to not die. When hackers enter through the holes in the fence, insert place some codes/scripts/tech-stuff (let's refer to them as magic spells) into iOS. Once done, every time the device reboots, their spell makes iOS boot without the usual restrictions allowing jailbreak content. Untethered jailbreaks are essentially powerful spells that are left inside the fence, working it's magic as long as it's untouched, even if the hacker does not enter anymore.




Tethered Jailbreaks
Tethered jailbreaks are a little more confusing. Sometimes hackers enter through the fence, but the area contains dangerous explosive that will detonate if the magic levels in the air gets too high. Therefore, to prevent devices from blowing up (just kidding, iPhones don't explode, everyone knows that it's Siri who dies) the spells they cast cannot be as powerful, leaving half the spell sitting inside the fence, while the other half has to be brought in from the outside each time the spell is required. Therefore every time the device reboots, without the external spell, devices with tethered jailbreaks cannot boot, stuck forever at the Apple logo screen till the phone dies.

To boot successfully, the user needs to plug the device into their computer. Using programs provided by the hacker, the other half of the spell is inserted through the fence and BOOM, the spell is in full power and the device boots successfully into its jailbroken state.



Semi-tethered Jailbreaks
Semi tethered jailbreaks are fairly new, beginning only in iOS 5. When there is only a tethered jailbreak available to the public, people are fairly apprehensive. What happens if their device requires a reboot, or runs out of juice during a trip where a computer is not accessible? Installed through Cydia as a package/tweak, semi-tether protects the user from the downside of tethered jailbreaks. When the device reboots without a computer, semi-tether allows the device to boot into a usable state, just without all the jailbreak contents. Basically you can call, text, and all the basic original iDevice functions. Just no Cydia or any jailbreak tweaks and themes. How this is done is beyond my little brain, but may God bless the person who came up with this. Read more about semi-tethered jailbreak here.


Summary
Untethered jailbreaks are the best, because the device functions fully like a normal device, plus jailbreak contents. 

Tethered jailbreaks requires the device to be attached to the computer every time the device reboots, otherwise the device will be stuck at the Apple logo startup screen; at least until it is tethered to a computer and rebooted again.

Semi-tethered jailbreaks are originally tethered jailbreaks, which the device user then goes into Cydia and install the semi-tether package/tweak. Semi-tether protects the user from the disadvantages of tethered jailbreak, while waiting for a full untethered jailbreak to be released.

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