There is no mobile emulator that needs a BIOS file because there is no finished emulator. Until Xenia is rewritten for ARM (or a new emulator appears), you must rely on cloud streaming.
Unlike many older console emulators, aX360e simplifies the user experience by often automating firmware requirements. In some versions, the emulator adds required firmware during installation. Xbox 360 Emulator Android Bios
: The leading emulator, Xenia , has no official Android port. There is no mobile emulator that needs a
No legit Xbox 360 BIOS + emulator for Android exists. Any site offering one is fake or malicious. Xbox 360 Emulator Android Bios