Fastboot is a protocol used to update the flash file system in Android devices via a USB connection. It operates outside of Android itself, residing in the device’s bootloader. Common uses include:
For a device to communicate with a PC in Fastboot mode, the correct USB driver must be installed on the computer. blackberry fastboot driver
In the command prompt, type:
fastboot devices
If a serial number appears, the driver works. If not, you will see nothing. fastboot devices — verify device connected fastboot oem