Illustrative embodiments disclose a data processing system providing low-level hardware access to in-band and out-of-band firmware. The data processing system includes a plurality of chips that includes at least one processor chip and a plurality of support chips. At least one processor chip includes a field replaceable unit support interface master that uses a field replaceable unit support interface serial transmission protocol to communicate with the plurality of support chips. Each one of the plurality of support chips includes a field replaceable unit support interface slave in, with ones of the plurality of chips that include a processor also include the field replaceable unit support interface master, and ones of the plurality of chips that do not include the processor include only the field replaceable unit support interface slave. Only the field replaceable unit support interface master possesses conversion logic.