Apparatus and method for verifying firmware used by a programmable processor in a processor-based device, such as but not limited to a solid-state drive (SSD). In some embodiments, the firmware is stored in a device memory and is accessed to generate an output value using a suitable mathematical function, such as a cryptographic function, a cyclic redundancy check (CRC) function, etc. The output value is used to verify a state of the firmware, such as by ensuring a proper version of firmware has been loaded, that an attacking party has not tampered with the firmware, etc. The firmware may be subsequently loaded and executed by the programmable processor responsive to successful verification. A nonce value supplied by a host can be incorporated into the output value generation process.