Unlocking bootloader is fairly simple and is just like any other android device as oneplus supports unlocking bootloader and it does not void warranty as well.
Set Up Fastboot & ADB Drivers:
What’s ADB? ADB stands for Android Debug Bridge. It works when the device is powered on and booted into OS or Recovery. The tool helps in sending basic linux commands, and a variety Android specific commands from PC to connected Android devices.
What’s Fastboot?Fastboot works only in bootloader/fastboot mode. It allows you to re-flash system partitions on your Android device and requires a device with an unlocked bootloader. It’s particularly useful when you want to update your device manually or in a rare situation when you accidentally soft-brick your device and need to install a clean stock system image.
Thanks to XDA member Snoop05 who has developed a small program to quickly install both ADB and Fastboot files on your PC (system-wide) along with proper drivers.
Downloads and installation instructions below:
HOW TO SETUP ADB AND FASTBOOT IN 15 SECONDS
Download 15 seconds ADB Installer (9.1 MB)
1. Download the adb-setup-1.3.exe file from the download link above.
2. Double-click/Run the adb-setup-1.3.exe file.
3. You will see a command prompt window with blue background. Say YES to all the prompts on this screen.
└ To say YES, just typeYand hit enter.
Once ADB, Fastboot and Drivers are installed, the setup window will automatically close and you’ll have a working ADB and Fastboot setup throughout your system.
Unlock Your Bootloader
Backup important files stored on your OnePlus 2 before proceeding with the steps below, as unlocking the OnePlus 2 Bootloader will completely wipe/delete all files on the device.
After the installation of drivers (OnePlus 2, Fastboot & ADB drivers) follow the below to proceed with Unlocking the Bootloader of your Oneplus Two
1. Enable USB Debugging:
§ Go to Settings > About phone, and then tap ‘Build number’ 7 times or until you get the message ‘You’re now a developer!’.
§ Go back to Settings, choose ‘Developer options’. Find the ‘USB debugging’ option and use itstogglebutton to enable it. Accept warning by tapping on OK button.
2. Connect your OnePlus 2 to PC now. You will get a pop-up as shown below on your phone when you connect for the first time after enabling USB debugging. Select ‘Always allow from this computer’ checkbox and then tap on OK button.
Boot your OnePlus Two into Bootloader/Fastboot mode. (Make sure you have backed up all important data as you’ll lose everything on phone in the steps below.)
Connect your OnePlus Two — in Bootloader mode — to PC. Let the driver install.
Open a command window on your PC. For this:
Open any folder on PC. Now, left click on empty white space inside the folder.
Hold shift key, right click on empty white space to get a pop-up as shown below.
Choose Open command window here option from that.
You will see a command window open up, with location directed to unlock folder.
Power off your phone then boot into fastboot mode (power + volume up).
Connect your phone to your PC via usb cable.
Confirm whether fastboot is working. With OnePlus 2 connected to PC, run the following command in command window.
It should return your device serial number, if not you need to make sure your drivers are installed correctly.
Once you’ve confirmed your fastboot connection to unlock the bootloader use:
fastboot oem unlock
The device will now go through the automated unlocking process, just let it do its thing and it’ll boot up into Android.
You’ll see a new screen on your device. ChooseYes using Volume button specified and then use Power button to confirm it.
That’s it. The device will reboot automatically.
To confirm unlock status, reboot into bootloader/fastboot mode and you shall see the text unlocked now.
fastboot oem device-info
It should have a couple of lines there, both with the flag set to true.