Heimdall is a cross-platform open-source tool suite used to flash firmware (aka ROMs) onto Samsung mobile devices. Heimdall connects to a mobile device over USB and interact with software running on device known as Loke. Loke and Heimdall communicate via the custom Samsung-developed protocol sometimes referred to as the 'Odin protocol'. Low-level USB in Heimdall is handled by the popular open-source USB library, libusb.