[HOWTO] Unlock bootloader

Why must the bootloader be “unlocked”? Before flashing a custom ROM like /e/ you must unlock the bootloader otherwise the bootloader prohibits the custom ROM to boot. Most vendors only allow their own stock approved software to boot.

Warning: Unlocking the bootloader will erase all data on your device! Before proceeding, ensure the data you would like to retain is backed up to your PC and/or a online drive.

Working ADB and Fastboot
Developer options enabled

  1. Enable OEM unlock in the Developer options under device Settings, if present.

  2. Connect the device to your PC via USB.

  3. On the computer, open a command prompt (on Windows) or terminal (on Linux or macOS) window, and type:
    adb reboot bootloader

  4. Once the device is in fastboot mode, verify your PC finds it by typing:
    fastboot devices

  5. Now type the following command to unlock the bootloader:
    find the right command here (select your device and then click install, and search for the unlock command).

  6. Ensure that your bootloader is unlocked by running
    fastboot oem device-info