Odin89
Android Enthusiast
Use lg recovery tool to flash stock .kdz to full stock not just boot.img and recovery.img, if you wiped the system then you could be systemless. Id recommend flashing stock .kdz (google tools and use) then repeating bl unlock and twrp flash and root, use the directions in op specifically and the advice of the forum here to make it fool proof. Hope it helps

, super su package enable root access and installs super su to manage the root access permissions for the installed apps but you can't flash it without a custom recovery.