Bootloader-Relock LG G4 (H815) No Wipe, No Backups, All Versions

[MathiasR33]

Thx for being so polite....

Hello, dear MathiasR33

I am asking you with a very polite request for technical support. I upgraded after OTA Wi-Fi to the latest version of Android MarshMallow 6.0.
Please help me in the next steps.
The fastboot devices command does not work for me.
I post a screen showing the version of my Firmeware in the LGUP.
And Screen from the CMD console saying that the fastboot devices command does not work.

Please, help me, I am waiting for your answer.

Dear Luke Slovian aka "whitewolf1608",

I will now try to answer all your questions at once...

BUT, WHAT DO YOU EXPECT FROM SENDING ME SEVEN PRIVATE E-MAILS ON A SUNDAY EVENING??? And writing "I am addressing you with a very polite request..." at the beginning of every mail does not make it more polite!

So let's go:

"Hello Dear Mathias R33 I am asking you with a very kind request for your technical support - how can I block the bootlader in the LG G4 h815? Unlocking the bootlader I made on Android MarshMallow 6.0.
I am writing to you by e-mail because I see that you are not active in the xda forum. Please answer me by e-mail."

One way would be the method described above. As steadfasterX already mentioned it's not the safest way because you could loose IMEI and/or MAC... I used this to lock my bootlooped G4 by reviving it by disabling two cores, issuing the command and flashing stock again. So I had a bootlooped device with no message at the corner.

"I came back in my smartphone LG G4 H815 to Android Lollipop - File with Firmeware with the extension kdz, with Lolipop was flashing by the LGUP tool.
Dear Mathias Rasper - if I have an Android Lollipop in the LG G4 h815, is the bottloader, and the modem have the Lolipop version?
Dear Mathias Rasper, please let me know if I need to flash the kdz file from Firmeware Android MarshMallow to block your bootloader method?"

Flashing a kdz does not always overwrite everything... If you want to be safe about your modem/bootloader-version you should flash the zip's via TWRP. I made this approach on Marshmallow, so I would recommend doing the same.

"Is this Firmeware> H81520g_00_0720.kdz Is it the latest or is there any other Firmeware from that which is newer?
Please, help me with this topic which Firmeware from Android MarshMallow 6.0 is
the latest firmware with the Kd file extension
Is l in the firmware name H81520g_00_0720.kdz <the letter g means that
firmeware is a newer release from this> H81520D_00_0115.kdz
https://lg-firmwares.com/downloads-file/1335/H81520D_00_0115.kdz"

You should only be safe that the flashed zip's do match your Firmware-Version.

"Dear Mathias Rasper, can your guide be used on Windows?"

??? The guide is about flashing files and performing commands using TWRP. ADB, fastboot and moving files using USB might work under Windows...

"Hello Dear Mathias Rasper. I am asking you with a very kind request for your technical support - because after entering the first adb devices command, the CMD terminal in the Winodws 7 system responds. But I have a serious problem because after entering the second command fastboot devices the CMD console does not suit me."

If you are not capable of using ADB and/or fastboot boot for any reason you could still perform the command from an installed TWRP-Instance.

"I just updated to the latest version of the operating system via OTA Wi-Fi so Firmeware in my smartphone updated to me from Android Lolipop to the latest version of Android MarshMallow. The LGUP tool detects that my Android version of MarshMallow is version with h81520o number. I put a screenshot."

Where is the question? But thx for that Mail at 22:29.

"Dear Mathias Rasper, I am addressing you with a very polite request for forum support in this link> https://forum.xda-developers.com/g4/general/bootloader-relock-lg-g4-h815-wipe-t3680665/page2 # post77640298"

Do you really think I can help you more if you message me also here?

"Dear Mathias Rasper, I wrote a question under your post> https://forum.xda-developers.com/g4...k-lg-g4-h815-wipe-t3680665/page2#post77640298
I'm also thinking about other LG G4 users h815 - please write what you think about it. You want to move our conversation in the forum to this post>.
https://forum.xda-developers.com/g4/general/bootloader-relock-lg-g4-h815-wipe-t3680665/page2#post77640298"

That's what I'm doing here.

"Dear Mathias Rasper how to block the bootloader in the LG G4 h815 is it to close me the way to use Android Oreo 8.1?"

What? NO! You'll need an unlocked bootloader to install any 8.1-Custom-Rom. You might consider asking this question first in the future...

Mathias

 

[whitewolf1608]

Hello, thanks for your comprehensive answers.

I apologize to you that I have sent you so many messages at once.

Dear Mathias R33 after entering the command in the CMD terminal fastboot boot I have to wait for the device.

The adb devices command works correctly. The CMD console responds correctly - with a message.

Screenshot_1 - the adb devices command

Screenshot_2-the fastboot boot command - Waiting for any device

 

[Spaceboy60]

deleted

 

[Spaceboy60]

... Thx for your thread even if it is known that the unlock state is handled by misc partition but it's good to have an own thread for it now. Latest TWRP beta can save the unlock state since a while.

Just wanted to add: if you made a misc backup before unlock you can just restore your backup. You can even flash a misc of an extracted kdz.
Sent from my LG-H815 using XDA Labs

OK, I'm using WindowsLGFirmwareExtract where do I find misc from the extracted dz file, browsing through the files there's nothing named misc so I presume it's called something else?

Also when doing the commands from the first page i get (is this normal?):

dd: writing /dev/block//bootdevice/by-name/misc: no space left on device
32769+0 records in
32768+0 record out
(16 MB copied), 21.7 MB/s

should i flash the two files now or am i going to have a bricked device?

 

[steadfasterX]

OK, I'm using WindowsLGFirmwareExtract where do I find misc from the extracted dz file, browsing through the files there's nothing named misc so I presume it's called something else?

Also when doing the commands from the first page i get (is this normal?):

dd: writing /dev/block//bootdevice/by-name/misc: no space left on device
32769+0 records in
32768+0 record out
(16 MB copied), 21.7 MB/s

should i flash the two files now or am i going to have a bricked device?

The time I wrote this I didn't knew about the fact that there is no misc partition in a kdz. Even when you find one it is just a bunch of zeroes as you always start blank .

I don't know what you're trying to achieve here though . You can erase that partition and you will be locked again which means you should be pretty sure that everything is pure stock before !! Using lgup is the best way to ensure this. Then you can just use fastboot erase misc (do a SALT basic backup before is always a good idea!!)



Sent from my OnePlus 6T using XDA Labs

 

[Spaceboy60]

The time I wrote this I didn't knew about the fact that there is no misc partition in a kdz. Even when you find one it is just a bunch of zeroes as you always start blank .

I don't know what you're trying to achieve here though . You can erase that partition and you will be locked again which means you should be pretty sure that everything is pure stock before !! Using lgup is the best way to ensure this. Then you can just use fastboot erase misc (do a SALT basic backup before is always a good idea!!)


Sent from my OnePlus 6T using XDA Labs

Was trying to verify whether those error messages of "no space left" mean nothing has changed on the device and therefore I can reboot safely or that something has been written and therefore I need to flash the two zip files as per the guide here. Obviously don't want a bricked device so have been waiting for an answer before rebooting.

Would be grateful for a response. Thanks

 

[steadfasterX]

Was trying to verify whether those error messages of "no space left" mean nothing has changed on the device and therefore I can reboot safely or that something has been written and therefore I need to flash the two zip files as per the guide here. Obviously don't want a bricked device so have been waiting for an answer before rebooting.

Would be grateful for a response. Thanks

That's how dd works in this particular command using /dev/zero as input device. it will write as much zeroes as possible - until no space left . So yes the command ended successful . As said I hope you have pure stock before rebooting !!



Sent from my OnePlus 6T using XDA Labs

 

[Spaceboy60]

That's how dd works in this particular command using /dev/zero as input device. it will write as much zeroes as possible - until no space left . So yes the command ended successful . As said I hope you have pure stock before rebooting !!



Sent from my OnePlus 6T using XDA Labs

Well was running stock (used lg Bridge). However now the LG Logo appears and keeps annimating and led is flashing blue but it never completed boot.

 

[steadfasterX]

Well was running stock (used lg Bridge). However now the LG Logo appears and keeps annimating and led is flashing blue but it never completed boot.

Try Download mode and reflash with lgup

Sent from my OnePlus 6T using XDA Labs

 

[Spaceboy60]

That's how dd works in this particular command using /dev/zero as input device. it will write as much zeroes as possible - until no space left . So yes the command ended successful . As said I hope you have pure stock before rebooting !!



Sent from my OnePlus 6T using XDA Labs

Try Download mode and reflash with lgup

Sent from my OnePlus 6T using XDA Labs

Download mode is playing up a bit on my device (pressing keys don't work most of the time) . I have managed to flash a UK KDZ file after eventually getting into download mode. however must be the wrong firmware for my region as I get a mcc/mnc code error. Getting back into download mode is proving the mission an impossible mission at present time