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CoolBooter demo: the dual-boot tool for iOS
Developer Jonathan Seals recently released a new piece of work called CoolBooter, an interesting tool which allows some 32-bit devices to dual-boot different iOS firmwares. With a simple reboot it can allow, for example, switching between iOS 6 and iOS 9. Whilst this functionality is commonplace in the desktop computing world, booting multiple operating systems on iOS devices is much rarer.
Sebastien and I talked briefly about the tool on Let's Talk Jailbreak 157, and in this article I'll give some more info, as well as a video demonstration of it in action.
We are now up to CoolBooter Beta 5, and some additional information is also available. It currently supports the following devices:
iPhone 4iPhone 5iPhone 5ciPad 2iPad 3iPad 4Note that as the techniques used in its working are only available for 32-bit, all of CoolBooter's supported devices feature this architecture. I would not expect that to change in the near future either. Relevant tools such as Xpwn and kloader, which are probably used by CoolBooter, are likely the reason for this.
I tried out CoolBooter myself on a test iPhone 5, and it worked like a charm! The device was originally jailbroken on iOS 9.0.2, and can now boot both 9.0.2 and a jailbroken iOS 6.1.4 flawlessly. Seal's demonstration video shows the basics, but I decided to record the entire process from start to finish during my test.
The video shows initial installation process, reboot into iOS 6, Cydia installation on secondary OS, demonstration of decreased storage space after installation, and demonstration of secondary OS version in Settings app. I then perform one reboot cycle between the two OSes, to show how the process works after the initial installation.
You can check out that video below. Please note, the video has been edited to shorten it. The steps take considerably longer in real life: