1. A method, comprising: executing a pre-boot application within an emulated pre-boot environment to test functionality of the pre-boot application, the emulated pre-boot environment executing within a user mode of a processor of a processing system during an operating system (“OS”) runtime of the processing system; and interacting with a hardware device of the processing system in response to the executing of the pre-boot application via a kernel proxy agent executing in a kernel mode of the processor.