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 IÂ 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.