Unlocking the bootloader may void the device's warranty.
All existing data on the device will be erased.
Update: Nokia has disabled the unlock ability with the December MR. You can only unlock if you downgrade your phone to an old release first. You can get it at Nokia Care or by buying remote flashing services.
Before you start: Make sure that you have platform-tools downloaded on your PC. You need to open a CMD or Terminal window in the folder where you have saved the platform-tools, unless you have installed them system-wide.
• First of all, enable Developer Options by tapping 7 times on BuildID in "About phone".
• Then go to developer options and enable OEM Unlocking option.
• Now reboot the phone into bootloader/fastboot mode. You can use the adb command:
• Make sure the phone is detected in fastboot mode. Then send the OEM unlocking command:
fastboot flashing unlock
• That's it!
You can also do the unlock_critical if you plan to flash the bootloader.