not even this procedure works, but does it work with your tablet?
No, I would recommend installing Xposed and using the module to do it. I hope that it wont cause you issues and I assume it wont because they fixed it in the newer version of TWRP. But if you still want to do it this way try this (this was confirmed to work by another user to get into recovery, I just had to search.) Apparently it is different that the G2:
Simultaneously press and hold the power and volume down buttons.
When the LG logo shows up, release the power button only.
Now press and hold the power and volume up button while keeping your hold on the volume down button.
When the factory reset screen appears, release your hold on all buttons.
Press the power button to continue.
Press the power button again to confirm if you’re sure you wish to continue with the reset.
Sorry for all the confusion, searching seems to be the best idea lol