[STOCK][M][TMO] Guide H811 20i & 20o Bootloader Unlock + Root + TWRP

[SignatureBoy]

Note : This guide is for H-81120-I & H-81120-O the latest update any firmware version below it will cause hard-brick so be careful before attempting anything, i wont be held responsible.

As a user with less knowledge about Commands and all, i was searching for answers by reading threads here and there and found my answers though some time tricky and sometimes easy.
Also in reading those threads i found many fellow members stumble upon resulting Soft bricks and in some cases a Hard brick or can say making their beloved G4 a paper weight.

So i thought i must put some really easy steps in order to clearly guide people like me who are too noob to understand the sophisticated developers steps.
Another reason for this Thread is also i saw many people asking about how to etc after updating to 20-O update for our H811 MM.

Few things to Prepare before Start

1- Properly Install Drivers for your H811 Variant of G4, cant find them Install LG Bridge.
2- Read the Whole thread before starting anything.
3- Confirm that all requirements are full filled and your variant is capable of everything mention in the OP.
4- Enable Developer Option then inside it enable OEM unlock and Usb debugging.
5- Always use Command prompt as Administrator.
6- Make a folder name G4 and paste all the file required for the unlocking in it for easy access and remembrance.
7- For Safer side after unlocking the bootloader boot into TWRP from fast boot and do not install TWRP.
8- Flash your SuperSU after that boot into android and see if all works.
9- Again Via Fastboot boot into TWRP make a backup of everything working fine. Boot into android.
0- Again same Via Fastboot boot into TWRP and now install your TWRP image via TWRP install function. So if by any means this is the culprit you can still revive your phone via your backup.

Attachments to Download

1- Adb Package can be found Here.
2- Download the latest TWRP.img 3.0+ from Here . This file needs to be on your computer and external sdcard.
3- Download the latest SuperSu zip (2.67+) from Here [Thanks to Chainfire] and stick on external sdcard as well.

Since downloading is complete now simply unzip the adb folder (containing fastboot by default) and paste both the TWRP image file and SUPERSU zip inside it.
Now Hold Shift and Open Command prompt here.

1- Input command to see if your device is visible in ADB.

adb devices

if you see your device and the status is off line then there will be a prompt on your G4 screen waiting for approval, accept it and input same command now all will be fine.

2- Now input below commands one by one. ( All credits to Autoprime )

adb reboot bootloader ( This will reboot your device to Fastboot mode )
fastboot oem unlock ( This will wipe all your data )
fastboot getvar unlocked ( This will check your bootloader status: Should be successful )
fastboot boot twrp-3.0.2-0-h811.img  ( Phone boots TWRP ) Please put the full file name with .img extension or it wont work.

3- Now the Phone should be in TWRP install SuperSU from there which you have already pasted inside your external SD card.
4- Reboot to system and see if SuperSU is installed. In some cases First flash of SuperSU does not work if your case is same the again boot to Fastboot and from there boot into recovery, since your bootloader is unlocked no need to repeat the unlock OEM command.
5- Now for safer side follow the steps 7, 9, 0 mention in Preparation heading above.

Hopefully all will be in your favor.

Useful Links if you still fail

Kdz 20-O after download must be unzipped

H81120o_00_0613.kdz

LGUP Software:
( All credits to MicroMod777 )

Disclaimer: Nothing in this thread is my work, if i have missed any credit please do let me know i will add. I know several guides are available for same purpose so if any body finds it offending any rights can ask the moderators to remove this thread. The purpose only is to guide simple people like me to save their devices from getting bricked.

 

[SignatureBoy]

As by reading the thread many people are falling for permanent TWRP installation as its mention in the OP anyways for people not getting permanent Recovery follow below:

Boot to TWRP from fastboot Bootloader
When recovery comes up click Install >>>> then in the right below corner you ll see a tab for IMAGE >>> press it browse the recovery IMG which you stored in your SD card >>> swipe to flash >>> From asking where to install >>> select recovery >>> DONE.

 

[DrakenFX]

Attachments to Download

1- Adb Package can be found Here.
2- Download the from Here . This file needs to be on your computer and external sdcard.
3- Download the latest SuperSu zip (2.67+) from Here [Thanks to Chainfire] and stick on external sdcard as well.

Indeed needs to be in both but needs to be in the same Folder as Fastboot file, if not wont work.
beside will be cool if you add a NOTE about if they are in 20o they must stick with 20o base roms, if not they'll get Hard-Brick.

 

[SignatureBoy]

Indeed needs to be in both but needs to be in the same Folder as Fastboot file, if not wont work.
beside will be cool if you add a NOTE about if they are in 20o they must stick with 20o base roms, if not they'll get Hard-Brick.

the ADB package i uploaded contains the Fastboot inside it
The thread clearly states it for 20-O

 

[DrakenFX]

the ADB package i uploaded contains the Fastboot inside it

ok i meant the TWRP file needs to be in the same folder where Fastboot file is

 

[SignatureBoy]

ok i meant the TWRP file needs to be in the same folder where Fastboot file is

That is also mention if you read the first post,

Since downloading is complete now simply make a folder and put all files downloaded inside it unzip the adb folder and paste both the TWRP image file and SUPERSU zip inside it.

 

[ApokrifX]

beside will be cool if you add a NOTE about if they are in 20o they must stick with 20o base roms, if not they'll get Hard-Brick.

The thread clearly states it for 20-O

Guys,
If I read it right:
LG G4 must be on 20o (stock) to follow this instruction.
If it’s on 20i or below, it must be updated to 20o (OTA or whatever) first!
It might be obvious for you, but not for me.
Again, but better be safe, then sorry.

 

[SignatureBoy]

Guys,
If I read it right:
LG G4 must be on 20o (stock) to follow this instruction.
If it’s on 20i or below, it must be updated to 20o (OTA or whatever) first!
It might be obvious for you, but not for me.
Again, but better be safe, then sorry.

yes it is for 20-O only

 

[ApokrifX]

yes it is for 20-O only

Thanks for clarification. I’d change 1st post a bit:
Few things to Prepare before Start
0. LG G4 with 20o (stock) firmware.

 

[DanGarion]

When I do adb reboot bootloader it just boots me back into Android... shouldn't it take me to the Fastboot screen?

---------- Post added at 06:41 PM ---------- Previous post was at 06:39 PM ----------

When I do adb reboot bootloader it just boots me back into Android... shouldn't it take me to the Fastboot screen?

Nevermind, I forgot about OEM Unlock...

 

[bravo261]

thanks for the write up

 

[DsturbD]

This is not specific to 20o. It's the same steps we've been using all along. Nothing new to see here.

Sent from my LG-H811 using XDA-Developers mobile app

 

[kelvinkk]

problem with fastboot

Thanks you for helping:fingers-crossed:

 

[kelvinkk]

problem with fastboot

Hi,

I am a newbie in xda. I am trying to root and install TWRP into my lg g4. I am using software version H81120o. I checked enable OEM unlock and USB debugging. I have downloaded lg driver though lg bridge and all the files from the post. However, I got two problem while installing the twrp-3.0.2-0-h811.img.

1st problem (stuck here and need to reboot also not showing h811 on "the list of devices attached" after typing command "adb reboot bootloader"):

C:\Windows\system32>adb devices
List of devices attached
LGH811xxxxxxxx device

C:\Windows\system32>adb reboot bootloader

C:\Windows\system32>fastboot oem unlock
...
FAILED (remote: Already unlocked)
finished. total time: 0.012s

C:\Windows\system32>fastboot getvar unlocked
unlocked: yes
finished. total time: 0.004s

C:\Windows\system32>fastboot boot twrp-3.0.2-0-h811.img
cannot load 'twrp-3.0.2-0-h811.img': No error

2. 2nd problem(stuck here and need to reboot):

C:\Windows\system32>fastboot boot twrp-3.0.2-0-h811.img
< waiting for device >

I checked online this problem might do with driver not up to date. Under device manager, my lg g4 is recognized under android device with android bootloader interface.
What should I do now?

Thanks you for helping:fingers-crossed:

 

[The Remedy]

This Root-Method worked like a charm... The only issue I'm running into is for the TWRP recovery to actually stick. When i manually reboot into recovery I get the little android guy with his chest open and the red triangle with the "!" in the middle.....am I doing something wrong by any chance??

 

[JasonG831]

I did everything but can't seem to get TWRP installed

 

[jdwatson2014]

Thanks a lot for this write up. I have been trying for about 2 weeks to root my g4 and it worked finally, So many thanks to you

 

[fuzzy_]

This Root-Method worked like a charm... The only issue I'm running into is for the TWRP recovery to actually stick. When i manually reboot into recovery I get the little android guy with his chest open and the red triangle with the "!" in the middle.....am I doing something wrong by any chance??

same problem here but I just now got it working...sort of . I still can not make anything come up except the factory data reset when I use the phone volume and power button.

I thought it might be just that I wasn't coordinated enough so I downloaded this small app to do a recovery reboot.

After I installed the app and used it, I got the little android guy with his chest opened with the red triangle. I took out my battery, put it back in and booted my phone with the power button.

I then connected my phone to computer via usb and went back into adb and opened TWRP and installed the twrp-3.0.2-0-h811.img again but this time I looked around a little more first, and noticed a setting to either install in boot or recovery partition. I selected recovery partition (neither were selected) and installed it. Now I can boot to TWRP recovery with the app I installed but still nothing but factory data reset with the volume and power buttons. I can live with this for a while until I can maybe find a solution.

 

[CardinalDeath]

I had the same issue but when u get into twrp make sure the IMG is in your SD card and to permanently have twrp installed go to home and press install.. Choose from image and install hope this helps

Sent from my LGLS992 using Tapatalk

 

[fuzzy_]

same problem here but I just now got it working...sort of ................

Now I can boot to TWRP recovery with the app I installed but still nothing but factory data reset with the volume and power buttons. I can live with this for a while until I can maybe find a solution.

In regard to booting into TWRP recovery with just the power and vol buttons, I just read this on another thread:

It boots into what appears to look like a default LG G4 factory reset page. For me, i clicked reset, and then yes, and surprisingly it brought me to where i wanted to go. TWRP Recovery.

I tried this and it worked for me as well.

I had been there before and tried it and it did a factory reset after I had spent an hour or two tweaking my phone, I was not a happy person. This time I did feel almost positive I had TWRP installed correctly and did not have nearly as much time spent getting things set up like I want them on my phone...It was still scary pressing that reset button and yes button.

If you don't have TWRP (or maybe some other recovery) installed it will factory reset your phone. I just thought I would share this and what happened with me. Do it at your own risk.