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LG G3 D852 Telus/Koodo Version Rooting And TWRP Recovery Installation

The tutorial will walk you through the steps on how to properly root and install TWRP custom recovery on your Canadian Telus/Koodo LG G3 D852 (Also works for Bell/Rogers variants).

Preface
The common way to install TWRP on G3 is first to root the device and then use Autorec to install TWRP. This method is quick and dirty, but it can lead to problematic kernels which can break many functions (such as camera/phone not shutting down without battery pull) on your phone. This is why I strongly advise against using Autorec especially if you have the Telus/Koodo version of G3.

I will first explain the process behind rooting/bumping your phone, and why Autorec can cause potential problems. I will then walk you through the process of doing it properly.

Disclaimer
I will not be responsible if you brick your phone. Use this tutorial at your own risk. Read the entire tutorial before proceeding.

Prerequisite Knowledge
There are many partitions on your android phone. For the purpose of this tutorial you need to learn the following partitions:

  • aboot: bootloader (the thing that basically loads everything)
  • laf: storing the program and files for download mode
  • boot: loading the system, ramdisk, and kernel
  • recovery: storing the recovery program
  • system: storing the android OS (AKA ROM)

Our G3 bootloader is locked, this prevents us from installing unofficial images onto other partitions (phone stuck on boot logo). It does so by checking whether partitions are “signed” or not.

To circumvent this, developers have found a way to bypass the bootloader security check. This method is commonly refrerred to as “Bump” for our G3.

So how does bump work? It fake signs our custom/modified partition to trick the bootloader thinking that our modified partition is legit and allow it to load. These fake signed partitions/images/zips are referred to as bumped.

Logically, we don’t want to flash anything not bumped onto our G3. Most custom ROMs and recoveries are already bumped. However, before you do anything you need to get your boot partition bumped! Else your bumped ROM/Recoveries will not load. In order to bump our boot partition, we need to first gain root access.

We will use one application: “ImageprepGUI” to achieve all these steps.

Preparation

  • Return to stock Lollipop (this method only works with Lollipop or Kitkat). If you are on Marshmallow you can revert to Lollipop by following this tutorial on XDA.
  • Extract and Install LG Mobile drivers: Download
  • Extract Install ImageprepGUI: Download (Created by XDA:topet2k12001)
  • Extract KitKat aboot and laf images (D852): Download
    If you are flashing a non D852 G3, you need to download your own version of aboot and laf here
  • Download Bumped TWRP recovery: Download 
  • Revert everything back to stock lollipop if you flashed a custom recovery or used Autorec(Autorec has the revert back to stock function).
  • Enable USB Debugging on your phone
  • Open device manager and make sure there is only LGE Mobile in COM port. Temporarily disable any other devices that is present.

Summary of Steps
The Imageprep program does the following thing for you:

First Step: Rooting the device

You can stop here if you just want root. However, you won’t be able to flash any custom images/zips (It will soft brick your phone).

Second Step: Make your phone vulnerable to Bump

Before bumping our boot partition, we need to make the phone vulnerable to the bump exploit. This is done by flashing KitKat versions of aboot and laf images. This needs to be done or else your bumped boot partition will not load. Don’t worry, KitKat aboot/laf will not interfere with your lollipop/marshmallow ROM. As long as you have the correct boot partition your ROM will run flawlessly.

Third Step: Bump our boot partition

In order to flash anything that’s bumped, we need to further prepare our phone by bumping the boot partition. This is where Autorec messed up. Autorec flashes a bumped boot image that contains a wrong kernel for our Telus/Koodo G3 (It uses the Rogers/Bell version kernel which is slightly different from ours)
ImageprepGUI does it correctly by first extracting the stock boot partition from our phone, bump it and flashes it back.

Fourth Step: Installing Bumped TWRP custom recovery

How to Use ImageprepGUI

  1. After installation, go to C:/ImageprepGUI. Run imageprepGUIv2.6.exe as administrator. Make sure you have all the necessary files as stated in the preparation section.
  2. Click through the introduction pages until you reach “Selection Option”
  3. Select “I have my own copies of KITKAT Image Files” and “I have my own copy of bump’d TWRP Custom Recovery”.        
  4. In the next page select the second option if you only want to root. Select the fifth option if you want to root, bump your device, and install TWRP. Option 1 and 4 is only for KitKat stock ROMs. If you are already rooted, you can use option 3 to bump and install TWRP.
  5. The program will ask you to locate the aboot.img laf.img files and the TWRP image file you downloaded.
  6. After that just follow the program’s instructions. You will have to grant ADB connections and superuser permissions on your phones so make sure to keep an eye on both the phone and the computer as the program runs.
  7. Enjoy your bumped LG G3 D852 with correct stock kernel!

Conclusion 
Once you finished running the program, ImageprepGUI stores copies of the un-bumped and bumped images on your SD-Card in a folder named ImageprepGUI. Save those img files as they can become useful later on.

If you want to use other Lollipop ROMs, it is recommended that after flashing the ROM you flash your own bumped boot.img again. Since most ROMs include kernel for the Roger/Bell version of D852.

Currently our Telus/Koodo version of G3 D852 doesn’t work well with other Marshmallow ROMS because Telus has not released MM yet so we don’t have a proper kernel. When Marshmallow comes at the end of the month we can do the same thing, then use our proper kernel with other MM ROMS like Fulmics.

Visit HERE to download the latest official Telus/Koodo Marshmallow ROM for D852.

Buy Me a Coffee
It takes time to write this tutorial. If you find it helpful why not support me by buying me a coffee?

 

Credit
This tutorial is based on my research in the XDA forum. None of this would be possible without the developers who made the tools available.

References

  1. [GUIDE][ROOT] Newest Root Method for LG devices
  2. [GUIDE][ROOT][BUMP][TWRP] ImageprepGUI: Auto-script GUI Root+Bump+TWRP for LG G3
  3. [GUIDE] 06/16/15 – Flash TWRP W/ AutoRec thanks to @bender_007 Stock Rooted/Lollipop

10 thoughts on “LG G3 D852 Telus/Koodo Version Rooting And TWRP Recovery Installation

  1. My phone is LG G3 D850 AT&T , phone’s software is LG G3 D852 Marshmallow stock ROM, Can I use this method?
    I rooted my phone with Kingroot but Root Lost after Rebooting, What should I do?
    Can you find a AutoRecMMD852.apk or AutorecLollipopD850.apk please?
    thanks for everything

    1. You can still follow the tutorial, but you need to use D850 Aboot & laf images instead. You also need to find ROMs for D850.

  2. Is this still valid with the new MM autorec and kernels available for d852 specific.

    I have issues with CM roms where if the phone is off and charging… you cannot turn on without removing the cable… also sometimes trying to reboot there is just a random black screen unti battery pul.

    will doing this whole process fix those by any chance?

    1. CM kernel is not as stable as the official kernel. If you want a bug free phone your best bet is to install the official ROM, the rooted version can be found here.

  3. Bell/Sasktel D852 won’t root from LP. It hangs during the cmd screen. I tried to ctr+c method to push it along, but it never actually roots. The whole process runs from start to finish, but when I check for root, it’s not there. One-click root doesn’t work either.

    1. i have the same issue it, in DOS it shows enter , leave
      # and nothing happens its just stuck on that page

  4. Just wanted to thank you for putting together this guide! Not new to rooting, custom roms/recoveries and such but with all the variants of the G3, finding this stuff step by step for the Telus D852 was quite the task, out of all the reading I did, your guide was the best, and has my phone buzzing, bumped with TWRP and all! Thanks! 🙂

  5. I originally used AutoRec to get TWRP installed, but didn’t like that it messed up powering off the phone and having to pull the battery to be able to power it on again, so I tried this method out. I reflashed with LG UP and re-did the method and as soon as TWRP is installed, it does the battery thing again. I do appreciate you writing out the guide though.

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