If you are looking for BIOS files to set up the Xenia Xbox 360 emulator , the most important thing to know is that Xenia does not require external BIOS files to function.
Significance of Xenia BIOS Files
This guide explains why Xenia is different, how it handles system software, and what you actually need for a complete setup. 1. Why Xenia Doesn't Need BIOS Files
When you launch Xenia, it loads the bios file into memory, which allows it to initialize the emulator's virtual hardware. The bios file contains a set of instructions that tell the emulator how to configure the virtual hardware, such as the CPU, GPU, and memory. This process is similar to how the Xbox 360's BIOS initializes the console's hardware.
Unlike many other high-level emulators, Xenia does not require any Xbox 360 system or BIOS files