DFU (Device Firmware Update) is a special service mode available in many Apple devices for recovering corrupted devices by uploading a clean copy of the firmware. Forensic specialists use DFU during checkm8 extractions (Elcomsoft iOS Forensic Toolkit). Unlike Recovery, which serves a similar purpose, DFU operates on a lower level and is undocumented. Surprisingly, there might be more than one DFU mode, one being more reliable than the others when it comes to forensic extractions. The method described in this article works for the iPhone 8, 8 Plus and iPhone X.

A pre-requisite to successful forensic analysis is accurate information about the device being investigated. Knowing the exact model number of the device helps identify the SoC used and the range of available iOS versions, which in turn pre-determines the available acquisition methods. Identifying the iPhone model may not be as obvious as it may seem. In this article, we’ll go through several methods for finding the iPhone model.

The Device Firmware Upgrade mode, or simply DFU, just got a second breath. The ability to image the file system, decrypt the keychain and even do passcode unlocks on some older iPhone models has been made possible thanks to the checkm8 exploit and the checkra1n jailbreak, both of which require switching the phone into DFU. The procedure is undocumented, and the steps are different for the various devices.

Highly recommended: Burned, Dropped, Drowned: HDD Recovery In Pictures. I hope that you will not encounter into such situations, though :).