[G4 General] MathiasR33:
Thx for being so polite....

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://xdaforums.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://xdaforums.com/g4/general/bootloader-relock-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://xdaforums.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