Device Firmware Update

Device Firmware Update (DFU) mode is an alternative boot mode for systems running on Apple processors, such as iOS, iPadOS, tvOS, watchOS, and macOS 11 or later. In devices running on an Apple A12, S4, M1 processor or later, a seed bit is set in the Secure Enclave to protect keys for Class A, B, and C user data.

Usage
DFU is considered a deeper restoration process than recovery mode. As such, backing up data is stongly recommended before proceeding.