The TWRP recovery image is flashed successfully. Remove the battery to turn OFF the phone.
To boot in TWRP –
Press the volume down and power button. As soon as LG logo appears on the screen temporarily release the power key and hold it back again. Make sure you don’t release the volume down key in the entire process.
Now use volume down key to move down to “Yes” and select power key to confirm this action
Again use volume down to move to “Yes” and confirm with Power Key.
As the bootloader is locked you’ll see this warning screen it’s normal. Press Power key to continue
For the first time when you boot in TWRP, it’ll ask for the password, click on “cancel”.
Agree to keep the system partition read-only by swiping the bar towards the right as shown above.
Now we’re in TWRP but there’s a need to flash “no-verity-opt-encrypt-5.1.zip” file otherwise, the custom recovery will be replaced with stock recovery in the next reboot.
To do this first click on “Wipe” as shown above
Now click on “Format Data”
Type yes and click on the “tick mark” to start formatting.
Now go back to the first TWRP screen.
Before clicking on Mount, as shown above, we’ve to transfer the no-verity-opt-encrypt-5.1.zip file to the sd card.
Download the file from below link and transfer it to a micro sd card.
You can also download the file to Phone’s Internal Memory.
Insert the micro sd card in your LG Aristo
Now click on “Mount”
“Tick” MicroSD to mount it.
Now go back again to the first TWRP screen and click on “Install”
Select “sdcard1” and locate the downloaded zip file i.e no-verity-opt-encrypt-5.1.zip
NOTE: If you’ve downloaded the file to Internal/Phone memory you’ll find it in “sdcard” folder, a folder just above “sdcard1” as visible in 2nd screenshot above.
Click on the file “no-verity-opt-encrypt-5.1.zip” to install it
To confirm installation, slide the bar towards the right.
Now we’ve successfully installed TWRP. As we’ve flashed no-verity.zip file the custom recovery won’t get erased on booting the phone in recovery mode.
Now that the custom recovery is installed rooting is just a one-click process. Follow the next tutorial to root your LG Aristo.
If you’re facing any issues please let me know via the comment section below.
Source – Messi2050@androidforums