Jailbreak And SHSH blobs

Jailbreak and SHSH blobs can be very confusing for some people especially those that are new to the Apple world.

Knowledge they say is power. If you have knowledge and understanding on a particular topic you won't have issues dealing with that topic.
 
At the time of this writing, it is not recommended to update your iDevice to iOS 6.1.3 if you intend on jailbreaking your device untethered. Furthermore, save your SHSH blobs with the software listed above.

However, if you do not plan to jailbreak your device, feel free to update to the latest iOS version.

Apple devices are one of the best kind of devices out there. Its so simple to use and relatively stable and reliable but there things you need to know when using an Apple device. Continue after the jump.

 This piece is especially recommended for those that are new to using Apple devices and are wondering what all these terms means.

Jailbreak 

Jailbreak is an activity that involves the running of certain programmed codes on an Apple device in other to lift restrictions or boundaries on the Apple Operating System (iOS) placed by Apple while giving the user of the device super user or full access to the device's system. Jailbreaking allow one to run unsigned applications that naturally would not run if it wasn't jailbroken.
There are 3 kinds of jailbreak: Tethered, Semi-tethered and Untethered
Tethered: device will not boot up until its jailbroken again whenever device goes off
Semi-tethered: Some apps will not function when device is turned off/on again until a jailbreak is performed on the device
Untethered: device will perform well, apps will run well if device is turned off/on - no need to re-jailbreak

Untethered jailbreak is the most preferable form of jailbreak.
Brand new Apple device are not in a jailbreak state. Apple frowns at it. As far as Apple is concerned it voids your warranty whenever you jailbreak your device. However, used devices bought may already have been jailbroken. 

One of the ways you can know if a device is jailbroken is by the Cydia  icon on the home screen
Benefits: it gives you total control over your device and you can install whatever you please on the device

Software that help to jailbreak Apple products are numerous but the most popular ones are

Evasi0n
 

Redsn0w
 

Snowbreeze
 

Absinthe


At the time of this writing. Evasi0n is the tool recommended to jailbreak untethered iOS 6.0 - 6.1.2 on all devices.
Redsn0w is able to perform a tethered jailbreak on iOS 6.0 - 6.1.3 on selected devices

Downgrade
Downgrading refer to a process of Installing an earlier version of Apple's iOS on a device instead of the most current iOS.
Usually, whenever, a new iOS is released, it becomes impossible to install a previous version of the iOS. However, ways have been designed to make this possible provided SHSH blobs have been saved for that iOS one intends to install.

Downgrade is only possible for pre A5 devices. This means that iPhone 4S and 5  are not possible to downgrade. For example, an iPhone 4 with iOS 6.1.3 installed can be downgraded to iPhone 4 6.1.2 if the SHSH blobs are saved. However, iPhone 4S can't achieve that even if SHSH blobs are saved.
Furthermore, apart from the firmware or iOS downgrade, there is also a downgrade of something called baseband. Just like the iOS downgrade, baseband downgrade is only possible for iPhone 3G and 3GS but not possible for later generation of iDevices.

SHSH Blobs
This is a kind of file saved on all devices whenever an iOS is installed on  the device. Its a kind of signature that  accompanies all iOS that are installed on a device.
This file is also store on Cydia server for those that have a jailbroken device but can also be saved on a computer with the help of softwares like iFaith and TinuUmbrella.
The benefit of having saved SHSH blobs is that it gives certain devices (pre A5 devices only) the ability to downgrade their iOS in the future if they so please even if Apple isn't signing it on their servers anymore.

The recommendation is that one should always save SHSH blobs locally with the help of iFaith and TinyUmbrella just in case there is a need to downgrade iOS.
That is, when you upgrade your iOS, do a saving of the device's SHSH blobs and keep on your computer.


At the time of this writing, it is not recommended to update your iDevice to iOS 6.1.3 if you intend on jailbreaking your device untethered. Furthermore, save your SHSH blobs with the software listed above.

However, if you do not plan to jailbreak your device, feel free to update to the latest iOS version.

More terms would be added to the list. However, it is pertinent to note that proper information is needed before you upgrade to any firmware or attemp to jailbreak any iDevice .

feel free to ask questions on any term you do not understand and any task you are not sure of carrying out.