Downloading from ROM aggregation sites. We strongly advise against this, not just for legality, but for security: many public MCPX dumps are trojaned with malware or modified to break emulation.
This report details the technical function, historical significance, and implementation requirements of the Microsoft MCPX (Media Communications Processor) Boot ROM image within the context of , an open-source emulator for the original Xbox. Mcpx Boot Rom Image For Xemu