It is a protocol and a command-line tool primarily used for communicating with an Android device’s bootloader. The bootloader is a software program that runs before the operating system starts, responsible for initializing hardware and loading the operating system. This particular mode enables users to send commands to the device from a computer via a USB connection. An example of its usage includes flashing new system images, unlocking the bootloader, or performing other low-level operations on the device’s firmware.
Its significance lies in its ability to provide a direct interface to the device’s core software components, offering a method for recovery, customization, and troubleshooting that is not available through the standard Android operating system. Historically, it emerged as a way for developers and advanced users to modify and experiment with Android devices, going beyond the limitations imposed by the manufacturer’s default configuration. This capability is invaluable for tasks such as installing custom ROMs, rooting the device, or restoring it to its factory state after a failed update or modification.