The Xbox console uses several measures, including cryptographically signed code to obfuscate firmware. The primary method of executing homebrew code required installing a mod chip which could be flashed with a modified Microsoft BIOS. This BIOS allowed the system to boot unsigned executables (XBEs) and control several hardware variables, such as region coding and video mode. With the leak of Microsoft's official development kit (XDK), homebrew coders were able to write replacement Xbox GUIs (known as dashboards), games and applications for the Xbox.