WARNING: This is only for those who have WINDOWS PC with ADB and Fastboot Installed.
Check this ink guidance:
You must turn off your phone. Boot it into fastboot mode by pressing and holding volume up button + power button or select reboot to bootloader if advanced reboot is activated via developer options. The phone will display the word “fastboot” saying that it has successfully entered in fastboot mode.
Plug the phone into your PC, then open a command prompt window on the desktop (Shift + Right Click -> Open Command Window here) and type this:
This command will give you the list of connected devices. If your phones serial number shows up then you are good to go and you may now continue. If the phone is NOT listed, it indicates that your drivers are not installed correctly. In order for you to continue you must fix your drivers so that your phone is listed under fastboot devices.
If the phone has been recognized by the command above, proceed to unlocking the bootloader with this following command:
“Remember this Step will WIPE EVERYTHING off the phone so Backup all your Data, we mean EVERYTHING or in other words, WIPE ALL!”
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You would be greeted with a Unlock Bootloader Warning page, press the Vol button to select Yes and turn it Blue and Hit the Power Button to Execute the selection.
Your device will reboot, show you a Secure boot warning, reboot into stock recovery and wipe all data. Once done, your phone will reboot into the OS.
(c) Funk Wizard