How To Unlock Bootloader On LG G5 SE H840 European Variant

Last time LG added US Variant of LG G5 RS988 to the list of official bootloader unlock. Finally, LG has added another device to the list of Unlocking Bootloader. Yes, Unlocking Bootloader on LG G5 SE H840 European variant is official. In this guide, we will guide you on How to Unlock Bootloader on LG G5 SE H840 European variant with model number SE H840. Now European Unlocked version of LG G5 is now supported to bootloader unlock officially by LG.

Now you can unlock bootloader easily by following this simple guide on How to Unlock Bootloader on LG G5 SE H840 European Variant. Official Bootloader Unlock for European LG G5 SE H840 will also void the device warranty. So if you planning to unlock bootloader on LG G5 SE H840 European, then it’s always better to wait until your warranty gets over. In case if you have unlocked bootloader, then you can always re-lock the bootloader on your device anytime.

How To Unlock Bootloader On LG G5 SE H840 European Variant

This only works on LG G5 SE H840 European Variant. Don’t try this on any other model. Below is the full guide on How to Unlock Bootloader on LG G5 SE H840 European Variant. Follow the procedure carefully. It is a somewhat involved process, but the majority of the process has been simplified as much as possible.

What is Unlock Bootloader?

A Bootloader is a code which runs when we turn on our device. This code initializes some hardware and then loads the kernel and ramdisk, and gets the boot process going. So this process is known as Bootloader. The same concept applies to all the technical stuff such as Laptop, PC, Smartphones and any such device. Every Android OEM manufacturers lock the bootloader even though it is an Open Source. So if you want to try any CUSTOM ROM, it is impossible to load the CUSTOM ROM without the Unlock Bootloader. So Manufacturer made a policy of making the smartphone with Unlocked Bootloader will void the warranty. They want you to stick with the Stock ROM. Unlock Bootloader allows you to Root your android smartphone, Flash TWRP and Custom ROM in a simple easy method.


  1. Charge your phone up to 80% or 70%
  2. You will Loose warranty if you unlock bootloader
  3. Unlock Bootloader may wipe all your data, So make sure to Backup your Smartphone
  4. Make sure you have followed the steps properly. Don’t Skip and Read! – We are not responsible for any damage that you make to your phone.

What Do You Need?

  • Download Minimal ADB Tool – CLICK HERE or Download the Full ADB setup for Windows / Mac here 
  • Install the Minimal ADB or Full ADB Setup (Screenshot from Minimal ADB Tool) minimal-adb-setup
  1. First of all, enable the Developer Option
  2. To Enable the Developer Option, Go to your Settings -> About Phone -> Now Tap on the Build Number 7-8 Times until you see a toast message “Developer option enabledactivate-developer-option-lg
  3. Now you need to enable the OEM Unlock by going to Settings -> Developer Option and Enable OEM Unlock oem unlock
  4. Download the Minimal ADB or Full ADB Zip and install/Extract it on your computeradb-folder
  5. Now note down the IMEI No of your device by dialing *#06# (Make sure note it down)
  6. Turn off your phone, now boot your phone into Bootloader by pressing Volume Up + Power Button Simultaneously. Now you will see a fast boot/bootloader
  7. Now go to the folder where you have extracted the ADB and Fastboot Tools
  8. Plug the phone into PC using USB Cable, then open a command prompt window by pressing Shift Key + Right Mouse Click command
  9. Now turn your phone into bootloader -> Turn off your smartphone – Press and Hold Power and Volume UP button – You will see Fastboot mode – or else, you can type the command if your device is in ADB mode. ( phone should be turned on and connected to PC via USB Cable.)
    adb reboot bootloader
  10. If you are booted into fast boot, type the command below in CMD screen.
    fastboot devices

    command window

  11. This command will list the connected devices. If your phone serial number shows up you are good to go and may continue. If the phone is NOT listed this indicates that your drivers or cables are not installed correctly. if you want to continue, you must first fix your problem.
  12. If the phone has been recognized by the command above, proceed to unlock the bootloader. Remember, this step will wipe EVERYTHING off the phone. Take backup. In your command window, type
    fastboot oem device-id
  13. This fastboot command will return a character string. This is the Device ID which is needed to generate your unique unlock key.
    Example Device ID (PC user)$ fastboot oem device-id
    (bootloader) Device-ID
    (bootloader) CD58B679A38D6B613ED518F37A05E013
    (bootloader) F93190BD558261DBBC5584E8EF8789B1

    To generate your unlock key, you will need to paste together the 2 lines of output into one continuous string without “(bootloader)” or white spaces. In the example above, the Device ID would be:


  14. Now open the official Unlock Bootloader Website of LG: Click here to open
  15. Click Starting Unlocking the Bootloader at the bottom of this page to start the bootloader unlock process. If you are not logged into your account, we ask that you log in.
  16. If you didn’t register with your email id.
  17. After register click the Starting Unlock Button again
    Click Unlock
  18. Now you will have a screen to type your IMEI no, name and Device ID. Now enter the IMEI number which you note down.
  19. Paste the Device ID(Continuous String you created in step 13) in the Unlock Bootloader website of LGunlock Lg
  20. Click Confirm. If your IMEI number and Device ID are valid, the bootloader unlock key will be sent to your email.
  21. Now open the email and check for the mail sent by LG developer.
  22. In your email, you will find the attachment with unlock.bin, download and move the unlock.bin attachment to ADB and Fastboot folder
  23. Enter the command in the command window.
  24. Now when the phone is still in Fastboot mode/ Bootloader, enter the command below (“unlock.bin” is the bootloader unlock key you received in the email.)
    fastboot flash unlock unlock.bin
  25. You have unlock Bootloader on LG G5 SE H840 European Variant.
  26. Reboot your phone by entering “fastboot reboot” in the command window.
  27. To check if your device has unlocked the bootloader, then Connect your phone to a PC using a USB cable and enter “adb reboot bootloader” in ADB command window.
  28. Your phone will reboot into the fastboot mode. You can check if the device is successfully unlocked, you can check by entering command below and verifying that the response is “unlocked: yes”
    fastboot getvar unlocked
  29. Now you can reboot your phone by entering the command
    fastboot reboot-bootloader
  30. Click Enter and That’s it! Voila.! You have unlocked bootloader !
  31. You have completed the steps for How to Unlock Bootloader on LG G5 SE H840 European Variant.


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