This is the look of Inferno in the version of iOS 6 and seen on the iPhone 5.
Inferno is a diagnostic utility used for testing in the factories for certain logs and has a take off time that starts Bonfire.
Bonfire is used for log collection and device information used in certain tools like BurnIn, Smokey, Inferno and Earthbound for testing.
All tests are performed via a usbmux interface. During that time the iPhone displays a picture of a fireball. Partial output is displayed at the bottom like device name, the version of the Operating System, the battery percentage and the Inferno version being used.