1. A method of invoking heterogeneous instruction set architectures comprising: initiating a processor-based system using platform specific firmware, specific to a booting instruction set architecture; booting an operating system in the booting instruction set architecture; changing the instruction set architecture of the operating system to a first instruction set architecture; storing in a firmware storage an extensible firmware interface application program interface having: (a) a first configuration table containing interface services relating to the firmware specific to the booting instruction set architecture, and (b) a system table containing a plurality of platform specific firmware services relating to a plurality of instruction set architectures, wherein the plurality of instruction set architectures includes the first instruction set architecture; invoking extensible firmware interface services of the first instruction set architecture to execute on the processor-based system, by accessing the services corresponding to the first instruction set architecture in the system table, wherein the first instruction set architecture is different from the booting instruction set architecture used to initiate the platform; and invoking, by an operating system kernel in the platform during runtime one or more services available in the first instruction set architecture that are not available with the booting instruction set architecture.