A host computing device includes a host processor, host memory in electronic communication with the host processor, and an auxiliary service controller. The host computing device also includes a communication interface and a messaging interface between the host processor and the auxiliary service controller. A message handler is stored in the host memory. The message handler is executable by the host processor in response to detecting a messaging interface signal on the messaging interface. Execution of the message handler by the host processor causes a firmware update patch to be read from a shared memory region in the auxiliary service controller via the communication interface.