Volume buttons not working in fastboot mode (LG Leon H320) I'm trying to unlock the bootloader on my LG Leon (running on Android 5.0.1 Lollipop). I've followed SO many online tutorials, and most come down to one and the same problem:
First I create a backup of my phone using adb with

adb backup -apk -shared -all -system -f backupThree.ab


Then, after that's done in about an hour, I do

adb reboot bootloader


After that,

fastboot oem unlock


Up to there, it's all working fine and dandy, but then I get an option on my phone to choose yes or no using the volume buttons.
But whatever button I press, NOTHING happens. Nothing at all.
I understand that the process should be taking a fraction of a second, so I know I'm not just interrupting the process when disconnecting my phone from my computer and reinserting the battery, which is necessary to be able to start my phone again.
An I'm not able to find ANYTHING on this on the internet. Am I the only one?
The only thing I can find online is people that have broken volume buttons, but that's not the case here. Outside of fastboot, they work perfectly fine.

So what's going on?
If anyone could help me, it'd be very much appreciated!

Kind regards,
Kasper
I have almost the identical problem on a Rook phone from EE, which I understand is a carrier-rebranded ZTE Blade III A410. I  found this post by jbdubbs which might offer a fix, but I haven't tried it yet. Quote:


  When booting to fastboot with any sort of USB plugged in, your buttons on the side may not respond. In this case, pull the cable and hold down power + Vol Down until it reboots. The buttons should now respond and you can plug USB back in if you wish.


You can take a look at the original. There are a few other similar bugs described there.