To understand the BIOS, one must understand the hardware it controlled. The Xbox motherboard featured:
But what truly made the machine an Xbox, rather than just a weird PC in a box, was its firmware—the . original xbox bios
Every executable file (.xbe) on the Xbox is signed with a 2048-bit RSA private key known only to Microsoft. The BIOS contains the corresponding public key. During boot, the BIOS calculates a hash of the executable and compares it against the decrypted signature. If they do not match, the BIOS refuses to execute the file. The Heart of the Black Box: Understanding the