Here is the Android Nougat Firmware for AT&T LG G PAD X 8.0 V520 (aka LG-V520).
LGV520AT-00-V20f-ATT-US-DEC-21-2016-ARB00+0
The software version of this firmware is V20f, and the Qfuse (Anti-rollback) version is 00.
If your LG G PAD X 8.0 V520 is still with the Android M 6.0 Software Ware, You can upgrade it to Android Nougat by flashing the LGV520AT-00-V20f-ATT-US-DEC-21-2016-ARB00.kdz with LGUP tool.
The Stock firmware LGV520AT-00-V20f-ATT-US-DEC-21-2016-ARB00.kdz can also be used to unbrick/restore your LG G PAD X 8.0 V520 back to stock.
To unbrick AT&T LG G PAD X 8.0 V520 tablet:
LGV520AT-00-V20f-ATT-US-DEC-21-2016-ARB00.kdzLGUP DLL for LG V520
LGUP SoftwareLG USB Drivers
You need to install LG USB Drivers, LG UP Software and LGUP DLL for LG V520. and then download the LGV520AT-00-V20f-ATT-US-DEC-21-2016-ARB00.kdz
How to Flash kdz stock firmware with LGUP, Please check this guide.
