In some examples, a system receives an update image including a first device driver to execute in a pre-operating system (pre-OS) environment of the system, and detects a second device driver that is already in the system. The system accesses a pre-stored dynamically configurable policy in the system, the pre-stored dynamically configurable policy relating to selection from among device drivers in the pre-OS environment, and determines, based on the pre-stored dynamically configurable policy, an action to take in response to the update image.