First off, the bootloader isn't part of Android, it's what lets the device boot into Android. Device manufacturers generally want you to stick to the version of Android they preloaded on the device.

After that, a user should reboot to bootloader and apply the “fastboot OEM unlock” command in a terminal connected to the smartphone.

Type the command fastboot reboot to reboot your tablet. Congratulations! You have successfully unlocked or relocked your Google Nexus 10’s bootloader.

You can now Reboot to Bootloader, and Power down. Previously you were unable to do this.

Unlocking the bootloader and rooting your Galaxy Nexus is really only half the battle. There may come a time when you need need to lock everything back up, including that bootloader. Thanks to the ...

Unlock your bootloader, but do not flash your custom recovery yet. Reboot. Your device will force-boot into stock recovery, wipe data and cache, then reboot again.

An XDA Forums user confirms that after unlocking the bootloader, the Z Fold 3’s cameras were completely non-functional: facial recognition, loading the camera app, and trying third-party camera ...

If you previously attempted to install the popular Windows XP "Bootloader" hack, you may not be able to apply to firmware update required for using Apple's newly released Boot Camp software, which ...