Inferno 7C1023e

Inferno 7C1023e is, apparently, an internal firmware used for testing. It was discovered on an iPod Touch, but may be in use for other iDevices.

Legacy
Although Inferno comes in an IPSW, flashing it via iTunes causes an error. Inferno is flashed using PurpleRestore.

Interface
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.

However when display tests are run, different output is produced.

Media

 * Photo 1

Source
This has been seen on the Forums from Macrumors.