OnePlus 3T is going to be a developer-friendly device. To install/flash TWRP Recovery on your OnePlus 3T, you need to unlock the bootloader first on the device. Thankfully, OnePlus device is as friendly as Nexuses.
Backup important files stored on your device before proceeding with the steps below, so that in case something goes wrong you’ll have a backup of all your important files.
Don’t Worry We Are Going to share Step by Step Guide to Safely do that.
How To Easily Unlock OnePlus 3T Bootloader
1- Setup ADB and Fastboot on your PC. For help, use this link .
2- Enable OEM unlock and USB debugging:
Go to your phone’s Settings » About phone » and tap “Build number” Seven/Ten times. This will enable Developer options on your OnePlus 3T.
3-Now go to Settings » Developer options » and look for “Enable OEM unlock” option, tick the checkbox next to it.
4- On the same page, also tick the USB debugging checkbox.
5- Connect your phone to PC and open a command window on the PC.
6- Reboot your OnePlus 3T into Bootloader/
Fastboot mode by issuing the following command:
ADB reboot bootloader
? Check your phone’s screen, if it asks for “Allow USB debugging”, accept it by selecting OK/Yes.
7- Once it is booted into Bootloader mode, issue the following command to finally unlock the bootloader on your OnePlus 3T:
fast boot oem unlock
? This will unlock the bootloader on your OnePlus 3T and also completely wipe your phone while doing that. So make sure you backup everything important on your device before unlocking the bootloader.
8- Once the bootloader is unlocked, your OnePlus 3T will automatically reboot. In case it asks for bootloader unlock permission on the device, accept it.
That’s all. Your OnePlus 3T bootloader should be unlocked now and you can install/flash a custom recovery like TWRP on it.