Here's the modified dirtysanta method to root LG V20 and install TWRP. This guide will help you in rooting your device with much easier situation.
Before you begin:
Read this carefully and completely. In this tutorial, I will teach you how to root your Canadian LG V20 using DirtySanta method. As LG V20 H915 can be rooted with dirysanta method but after rooting signal/cellular service do not work. Due to this issue we need to convert H915 to US996 variant. There is already some guides for doing this but the catch in this guide is that you don't have to flash a H915 kdz --> Root --> Flash US996 rom --> US996 kdz --> Root --> Flash US996 rom.
This tutorial uses the potential of patched LGUP to skip long parts and makes the process more easy and comfortable. I got some inspiration for rooting from this thread
Before proceeding read 4th post carefully.
All things that you require for this process can be found in 2nd post.
1: Turn off your anti-virus as it can delete some rooting files.
Phase 1: (Converting H915 to US996)
1: Download all files given in 2nd post.
2: Extract and copy LGUP to "C:\Program Files (x86)\LG Electronics" (for 32-bit windows C:\Program Files\LG Electronics). (Location varies as per location of your windows installation drive)
3: Install LG Driver (If not already)
4: Backup any of your data if you need it because you will loss your data from internal storage.
5: Put phone into download mode. (Switch off phone, hold vol-up button and plug into pc while holding that button)
Phase 2: (Rooting our converted phone and installing a custom rom)
1: Download all files given here (A Root package and terminal emulator)
1: Connect phone to your PC while in download mode.
2: Run "LGUP.exe". It should detect your phone. If you need backup of your current OS then click on dump partition radio button on LGUP and select start. Click on select all when a pop-up appears asking for which partition to dump.
(Backup can take upto 20gb of space).
3: Select "PartitionDL" button from LGUP. Click on 3 dots button and select downloaded US996 kdz. Now press start.
(Click on select all partition when a pop-up appears about which partitions to flash) Wait till it finishes flashing.
4: After flashing is done. Your phone will boot into sysgem. Do some normal settings. (Do not login with any google account).
5: Now use this GUIDE to root your phone
If you're facing secure startup after rooting (even you disabled it), then you will have to factory reset your phone using TWRP.
6: As of now you have a stock rooted US996 converted phone. You can continue and flash a custom debloated US996 rom if you want and can stop here and use your phone
(You can flash any custom rom of your choice for US996)
7: Now boot into TWRP. Copy "US996_deODEXd_Stock_NRD90M.zip" in your phone.
8: Flash this zip through TWRP.
9: If you want to flash any kernel then flash supersu or magisk after flashing kernel.
Reboot phone into system and you will have custom Rom with root.