Digital Forensic Certification Practice Exam

In which phase of the UEFI boot process does the system transfer control to the OS?

1. Security phase

2. Driver Execution Environment phase

3. Runtime phase

4. Pre-EFI initialization phase

The correct answer is: Runtime phase

The phase in which the system transfers control to the operating system is the Runtime phase. At this stage, the Unified Extensible Firmware Interface (UEFI) has completed the necessary initialization of the system and is prepared to hand over control to the OS. During the Runtime phase, the firmware has finished executing all the earlier stages, including the Security phase, where security checks and validations occur, and the Driver Execution Environment phase, which involves loading drivers necessary for hardware initialization. Prior to the Runtime phase, in the Pre-EFI Initialization phase, the system sets up the hardware and prepares the environment needed for subsequent initialization processes. Once these initializations are complete, the Runtime phase occurs, enabling the operating system to start its own boot process and control the hardware. This clear delineation allows for a more organized handover from the firmware to the OS, ensuring that all necessary conditions and configurations are met before the operating system takes over the control of the system.