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.

We have discovered a way to unlock encrypted iPhones protected with an unknown screen lock passcode. Our method supports two legacy iPhone models, the iPhone 5 and 5c, and requires a Mac to run the attack. Our solution is decidedly software-only; it does not require soldering, disassembling, or buying extra hardware. All you need is iOS Forensic Toolkit (new version), a Mac computer, and a USB-A to Lightning cable. In this guide, we’ll demonstrate how to unlock and image the iPhone 5 and 5c devices.