Yes, that's how unlocking is done and it's identical to the procedure for Nexus devices. The reason there is no boot.img involved for unlocking is that unlocking is precisely what allows you to boot an unsigned image. This unsigned image then starts a small script that installs SuperSU and the su binary on your system partition.Hello
Sorry to bother you but is this method correct to unlock the bootloader ?
Connect your device to your computer using a USB cable.
On your computer, enter the following command:
fastboot oem unlock
This will display the unlock menu. Read the disclaimer and think one last time about what you are doing. This is your last chance to stop.
As simply as this ? no boot.img or something else ?
Thank you !
So after you unlocked your device, you will still need to boot a custom image to get root (as explained in the remainder of the document you cited), but unlocking itself only requires fastboot.