[LG G Pad X 8.0 Guides, News, & Discussion] jdub01984:
This was completed on the T-Mobile LG GPAD 8.0 X also known as the V521. It will probably not work on any other version except this tablet.

DISCLAIMER: Following these steps will void your warrant. I will not be held responsible for any damage you may cause while following these directions.

I did not build any of this code to do any of these steps. I have compiled them from a few places. The guide is going to walk you through updating your tablet to 7.0 using LGUP and the kdz. Then to install TWRP recovery and allow you to install SuperSU to gain root. We will be using the dirtycow method from the LG V20 Section of XDA, posted by jcadduono.

I'm not sure who coded all of these things, so I can't thank everyone who put the software and code together.

You will need all of the following to complete this guide:

ADB and Fastboot. I recommend Minimal ADB and Fastboot found here.

LGUP - I used the UPPERCUT version found here. Be warned that Windows Defender flags it as a trojan and you will need to disable Defender. If you are uncomfortable with that, then use the following method to get LGUP installed.

V521 7.0 KDZ file. You are looking for the file named V52120f_00_1209.kdz

TWRP

SuperSU v2.79 zip

Dirtycow armv7 Files. Download all 4 files. You may need to right click and save as to download them.

If you have your bootloader unlocked and want to install 7.0 and root skip to step 2. If you have your bootloader unlocked and have 7.0 installed, skip to Step 3 to install TWRP and SuperSU.

Step 1: Unlock your bootloader

The tablet bootloader is not unlocked by default. This is required for rooting the LGV521 (T-Mobile). You may unlock it by following these steps:

Warning: A bootloader unlock will wipe your tablet.

1. Enable Developer Settings (About tablet > Software info > Build number Tap 5 times)

2. Enable USB Debugging (Developer options) (Example)

3. Enable OEM Unlock (Developer options)

4. Install Android Debug Bridge (?)

5. Install LG Device Drivers if needed (Available below)

6. Open 'Command Prompt' and type in 'adb shell'

7. Enter these commands into ADB Shell for your device:

reboot bootloader
fastboot oem unlock
fastboot reboot

8. Check if the bootloader is unlocked by entering:

fastboot getvar unlocked

NOTE: While the bootloader is unlocked, you will get the "The software on this device cannot check for corruptions" message upon boot unless you install a modified boot image and kernel to get rid of the message.

Step 2 Install Nougat on your tablet.

Make sure you have USB Debugging Enabled in the Developer Options and the LG drivers installed.

Open LGUP with which ever method you choose above

Select the UPGRADE Bullet, and in the bottom section click the ... in the file path field and select the KDZ you downloaded above

Click start. Your tablet will reboot a few times and should install Nougat.

Once the LGUP screen says Completed in the STatus Field, you have nougat install. Proceed to Step 3 if you want TWRP and Root.

Step 3 Getting TWRP installed with DirtyCows and achieving root.

Make sure you have USB Debugging Enabled in the Developer Options and the LG drivers installed.

We are now going to copy the dirtycow files to the tablet, install twrp, and achieve root by installing SuperSU.

I suggest copying the 4 dirtycow files, supersu zip , and the twrp img you downloaded earlier directly into your adb and fastboot install location (Should Be "C:\Program Files (x86)/Minimal ADB and Fastboot" if you are using Minimal ADB and Fastboot.

Run the following ADB commands:

adb push dirtycow /data/local/tmp
adb push recowvery-applypatch /data/local/tmp
adb push recowvery-app_process32 /data/local/tmp
adb push recowvery-run-as /data/local/tmp
adb push twrp-3.0.2-x-xxxx.img /sdcard/twrp.img

adb shell

$ cd /data/local/tmp
$ chmod 0777 *
$ ./dirtycow /system/bin/applypatch recowvery-applypatch

<wait for completion>

$ ./dirtycow /system/bin/app_process32 recowvery-app_process32

<wait for completion, your phone will look like it's crashing>

$ exit

adb logcat -s recowvery

<wait for it to tell you it was successful> and Press [CTRL + C]

adb shell reboot recovery

<wait for phone to boot up again, your recovery will be reflashed to stock>

adb shell

$ getenforce

<it should say Permissive, adjust source and build for your device!>

$ cd /data/local/tmp
$ ./dirtycow /system/bin/run-as recowvery-run-as
$ run-as exec ./recowvery-applypatch boot

<wait for it to flash your boot image this time>

$ run-as su
#run-as exec dd if=/sdcard/twrp.img of=/dev/block/bootdevice/by-name/recovery

<wait for it to complete>

$ reboot recovery

You should now be on the TWRP screen. I like to adb sideload when I install here to save storage space on my tablet. Some users are having issues installing SuperSU with the sideload method. If you are you will need to format your data, by selecting wipe, and then format data. This will delete allof your data, but will remove the encryption and allow twrp to read/write to your data partition. If you have an external microsd installed you can also try putting the supersu.zip file on there and installing it from the sd in twrp. If that does not work then you will have to format the data partition.

Here is how to install SuperSU with sideloading:

Swipe right on the Swipe to Allow Modification slider

Click the Advanced Button

Click the ADB Sideload Button

Swipe Right on the Swipe to Start Sideload slider

and then run the following ADB command on your PC

ADB Sideload supersu.zip (replace supersu.zip with your actual supersu file path)

Once Supersu is completed click reboot. (Your system will reboot a few times) and you should end up on your lock screen with 7.0 installed and rooted.

Don't forget to give this post a Thanks.