[LG G8X ThinQ Guides, News, & Discussion] zdanee:
The rooting process is basically made up of 3 parts:

- unlocking the bootloader

(- if the fingerprint reader is broken, KDZ to Android 9)

- gaining access to your boot.img

- patching you boot.img

You will loose rooting between major updates, but you won't loose the open bootloader that makes rooting possible.

Some people suggest the fingerprint reader only has a problem if you have a fingerprint enrolled in it before starting the process, so to be on the safe side, delete all your enrolled fingerprints before starting.

You can do the rooting on Android 9, but then when you upgrade to Android 10 you might loose it, as the new image also has a new boot.img that you didn't patch before (if it were patched it would fail the cheksum test and would not install), so you'll probably have to do the rooting after a major update.

Before you start the process try to get ready, download all the tools, images you might need and make backups! You'll need:

- LGUP tool 1.17

- your KDZ for the earliest version you can get from LG-roms

- the latest KDZ you plan to actually use

- LG Drivers and ADB

- QFIL

- a patched abl_a file

- Magisk Manager

You also want a reasonably stable Windows PC you trust not to freeze during flashing and an USB-C cable you trust to work well.

1. I would advise to start straight with the newest ROM you can find, just because you'll have to use less the scary QFIL-mode. Remember: you'll have to patch the boot_a.img from the Android version you want to use, so probably Android 10. So, do all the software upgrades before you start. Or, you can try with your current version, and have the extra step to get your boot_a.img at a later point.

2. Next you do the bootloader unlocking (#3): https://xdaforums.com/t/un-bootloop...el-for-lg-g8-kor-g820n.4228257/#post-85143941

3. While you do the abl_a backup, make sure to also back up your boot_a, if you are on the Android version you plan to use. Check if your audio, network and fingerprint reader still works. If it does, skip the next part.

3.1: so something does not seem to work. You'll have to downgrade to Android 9 to fix it. Using LGUP 1.17 and the KDZ you downloaded earlier downgrade to Android 9 (just use LGUP 1.17 and the KDZ) and do the 4-step simplified fix: https://xdaforums.com/t/steps-to-ge...ng-with-unlocked-bootloader-and-root.4202287/

It's possible your earliest version of Android 9 is different from the guide, or that it won't work for that version. In that case download the next earliest version and try again. For my EU Hungarian T-mobile phone it was the 10d version that eventually worked.

3.2: now that everything works time to use LGUP again and upgrade to the latest version. Use KDZ, don't try to upgrade from within Android! Your unlocked bootloder will still work despite the reflashes.

If you are doing this on Android 9, then you have to use LGUP 1.17 and flash your latest KDZ at this point, go back to QFIL and make a backup of boot_a.img at this point.

4: Now you have a working phone, unlocked bootloader and the newest Android. Time to install Magisk Manager. Copy the previously saved boot_a.img to the phone and patch it from within Magisk Manager. Using QFIL once again flash the patched img to the phone. Done, that was it, you are rooted. Time for beer!