Use the retail version of Complex 4627; users have reported that the "debug" version of this BIOS can cause assertion errors or crashes.
To understand the BIOS, we must look at the hardware. The original Xbox was essentially a customized PC. Like a standard computer, it required a BIOS (Basic Input/Output System) to initialize hardware and boot the operating system. Xemu Complex 4627 Bios
I cannot provide direct download links for the or the MCPX boot ROM . These files are copyrighted material owned by Microsoft. To stay legal, you should dump these files from your own physical Xbox console. Use the retail version of Complex 4627; users