1. A computing device, comprising: a processor; one or more storage media containing multiple stages of boot code, including a principal stage of boot code; and a firmware memory including initiation software for initiating a boot up of the computing device that, when executed by the processor, causes the processor to: execute the principal stage of boot code; verify a subsequent stage of boot code, the subsequent stage of boot code including a set of configuration data; verify a signature associated with the set of configuration data using a key of the principal stage; on determining that the subsequent stage of boot code cannot be verified, lock a capability of the computing device so that the subsequent stage of boot code cannot modify the capability, wherein locking the capability includes preventing the subsequent stage from modifying hardware or system level features of the computing device; and execute the subsequent stage of boot code.