The Android Debug Bridge (ADB) is a toolkit included in the Android SDK package that allows you to control your device over USB from a computer, copy files back and forth, install and uninstall apps, run shell commands, and more.
Reboot to Normal Mode
Reboot to Fastboot Mode
adb reboot fastboot
Fastboot is a diagnostic protocol included with the SDK package used primarily to modify the flash filesystem via a USB connection from host computer. It requires that the device be started in a boot loader or Secondary Program Loader mode, in which only the most basic hardware initialization is performed.
fastboot oem unlock
fastboot reboot bootloader
fastboot boot <file.img>
fastboot flash recovery <file.img>
If you are having trouble with fastboot not executing commands and constantly having fastbootb display: < waiting for device > with your OnePlus 3T device, please make sure you have the correct device driver installed. It should be seen as a Kedacom USB Device> Android Bootloader Interface.