As soon as Apple's newest mobile operating system, the iOS 5, became available, a number of tools to help in jailbreaking emerged. But until now the only tools available provide a tethered jailbreak.
Developers have released a tethered jailbreak - meaning that the device, once jailbreak is installed, will only stay active until the next time you reboot - for various iPhones, the iPad 1 and iPods. The problem, of course, is that once you reboot the device, you will need to redo the jailbreak.
There is a tool that can help.
It's called SemiTether, and it is currently in a beta version. SemiTether lets you reboot a device that's been jailbroken, by using a tethered message, without getting stuck at the boot logo. Once you reboot, you will not have access to all of your device's functions. For example, you will not be able to run jailbroken apps or the Web browser. In addition, you will also not be able to use the Mail app and some others as well.
While hackers are continuing to search for a way to perform an untethered jailbreak, for now SemiTether is probably the next best thing. However, it does not work with the iPhone 4S or the iPad 2 because there is currently no way to jailbreak either device if it is running iOS 5.
Jailbreaking gives you a way to install software that originates from outside Apple's App Store universe, without the company's seal of approval. It also enables users to make unauthorized tweaks to the device's mobile operating system. Jailbreaking voids the user's warranty and could cause damage to the user's device if done improperly. This includes apps which can dramatically change the look and feel of the iPhone by altering features such as the boot animation, keyboard or notifications.