tldr/pages/common/fastboot.md

fastboot

Communicate with connected Android devices when in bootloader mode (the one place adb doesn't work).

• Unlock the bootloader:

fastboot oem unlock

• Relock the bootloader:

fastboot oem lock

• Reboot the device from fastboot mode into fastboot mode again:

fastboot reboot bootloader

• Flash a given image:

fastboot flash {{file.zip}}

• Flash a custom recovery image:

fastboot flash recovery {{file.img}}

• Display connected devices:

fastboot devices