BIG UPDATE:

The old, plain and simple trick to unlock bootloader, like we do on Google Nexus devices, isn’t working on the LG G4. Actually, LG has gone for the same method to unlock bootloader that is already under employment by Sony and HTC. You have to register at LG’s site, provide your device’s details to LG and obtain a file called unlock.bin from them. Then use fastboot to flash the unlock.bin file on your phone to unlock the bootloader.

We’ve got the whole procedure covered below, with pictures. If you are looking to unlock LG G4 bootloader, the below is all you need as help. Do know while unlocking the bootloader open the world of customization for you, enabling you to install custom recovery like TWRP and CWM, and thus allowing you to flash custom ROMs and mods, it has certain drawbacks. Main disadvantages of unlocking the LG G4 bootloader are: lose warranty, lose DRM (movie streaming apps may not work), and lastly, it cannot be undone — you will lose the above two permanently.

Hence, you may want to think twice before unlocking the bootloader. We would unlock for sure, because it’s hard to resist custom ROMs and mods, and have a backup made from TWRP. Not to mention root access, a must for me. But you know, since you lose warranty and there is no turning back, think twice before opting for LG G4 bootloader unlock method given below.

INSTRUCTIONS

WARNING: Warranty may be void of your device if you follow the procedures given on this page. You only are responsible for your device. We won’t be liable if any damage occurs to your device and/or its components.

Important Note:

Backup important files stored on your LG G4 before proceeding with the steps below, as unlocking the G4 bootloader will completely wipe/delete all files on the device.

  1. Enable OEM Unlock and USB Debugging in Settings first of all.
  2. Install LG G4 drivers. It’s a must, it helps PC to recognize your G4.
  3. Install ADB drivers. This installs required ADB and fastboot drivers and makes them available system wide. Using ADB, we would unlock bootloader.
  4. Get IMEI no. on PC. Install this app (IMEI Inspector), and open it. It will display phone’s IMEI no. to you. Tap on Share button, and using Gmail app, send it to yourself. You’ll need the IMEI no. soon in step __ below.
  5. On PC, register with LG’s developer site. Go here, and then under the ‘LG Developer Member’ section, click on ‘Countries other than Korea’.a
  6. Agree to terms and conditions and privacy policy, and then click on OK to move to next page.
  7. Enter your details, user ID and password of choice, and register yourself.
  8. Check your email, LG will sent you one confirming your registration, titled ‘[LG Developer] Please activate your new account!’. You have to click on the link provided by LG in the email to activate the account.
  9. Now, go to Login page. Enter your details and the click on Login button to log into your account.
  10. Now, go to the bootloader unlock page.
  11. Under Phone, select your phone, LG G4 LGH815, from the drop-down.
  12. Provide IMEI no. now. You have it in your email, copy paste from email to this field.
  13. Provide Device ID now. Well, this is tricky, here’s how you can do it.
    1. Connect your LG G4 to PC. And don’t disconnect until said so. (It should connect all fine because you already have the LG and ADB drivers installed from above.)
    2. If you are connecting the phone to PC for first time after enabling USB debugging, you will get a pop-up on phone, asking for permission to allow USB debugging, as show below. Select the ‘Always allow..’ option and then tap on OK.
      Allow USB Debugging
    3. Now, make a folder in C drive, and name it: g4unlock
    4. Go into g4unlock folder and open the command window from there. While holding shift key, right click on white empty space inside the folder to get a pop-up. Click on ‘Open command window here’ option.
    5. Reboot LG G4 into fastboot mode. Copy the the command below and paste it in the cmd window you just opened. 
      adb reboot bootloader
    6. Your LG G4 will reboot into fastboot mode now. To get Device ID, copy the command below and paste it in cmd window. 
      fastboot oem device-id
    7. You will get the Device ID in two long serial no. as shown below.
      device id lg g4
    8. You have to copy them one by one, not together because we don’t need any other text than the serial no. here. Copy serial no. one first. For this, right click on cmd window, and then on Mark option. Drag the mouse left button from serial no.’s first letter to its last letter. Then right click on the selected text. The selected the text will be copied. Paste this in the Device ID field on the device information page where you entered the IMEI no. above.
    9. Copy the second serial no. the same way, and paste it right after the first serial no. in the same field. Make sure there is no space between the two, second serial no. has to be right after the first serial no., otherwise it won’t work alright. Both serial no. need to be in one continuous string. The above two serial no. would be entered as shown below. In bold style is the first serial no. just for example, you don’t have to do it. And btw, neither close the command window nor reboot your LG G4, keep it in fastboot mode.
      CD58B679A38D6B613ED518F37A05E013F93190BD558261DBBC5584E8EF8789B1
  14. Click on Confirm button now. LG will check validity of the IMEI no and Device ID. If all is good, LG will send a file called unlock.bin to your email.
  15. Open your email, and look for LG’s mail containing the unlock file. Download unlock.bin file.
  16. Transfer the unlock.bin file to the g4unlock folder we created above.
  17. Unlock bootloader of LG G4 now. Copy the command below and paste it in cmd window. 
    fastboot flash unlock unlock.bin
  18. Once done, confirm the bootloader’s lock status by using the command below. As usual, copy paste it, or type manually if you have become fond of fastboot by now. 
    fastboot getvar unlocked
  19. If you get ‘unlocked: yes’ as response, it means your LG G4’s bootloader is now unlocked.

Happy flashing! A custom recovery (TWRP/CWM) isn’t available as of now, but once it is, we’ll be sure to get you an instruction set to help you install TWRP/CWM on your device.

That’s all. Enjoy!