Guide | How to Unlock Bootloader LG V20 (H918, H830, US996) Via Fastboot. 

Unlock Bootloader, TWRP LG V20. This guide below will show you how to unlock bootloader and install or flash TWRP recovery at Android LG V20 smartphone. There are many method used by most Android user to flash TWRP on their device. For example, flash TWRP via fastboot or flash TWRP via dirty cow exploit. Whatever which method you use, the main purpose is installing TWRP recovery on your device. So, by installing recovery on LG V20 you will start new fun on your hand. From take a full Android backup or called Nandroid until flashing new ROM or the other tweak on this device. 

Installing TWRP recovery on LG V20 is easy, the following method only work on LG V20 version mentioned below ;

1. H918 (T-Mobile)
2. H830 
3. US996 (U.S. Cellular)

So, if you aren't the owner of LG V20 versions above you can leave this guide. Before we proceed this guied, I would like say thanks to the official threat on xda for this awesome trick. check out here.

http://forum.xda-developers.com/v20/development/h918-recowvery-unlock-v20-root-shell-t3490594

Unlock Bootloader.

1. For LG V20 US996 (U.S. Cellular) user, you can try to unlock bootloader your device by following this guide below.

http://guidebelajar.blogspot.com/2016/11/guide-how-to-unlock-bootloader-on-LG-V20-US996.html

2. For other models, this step begins here.
• Download LG USB driver.
• Windows Here

http://redirect.viglink.com/?format=go&jsonp=vglnk_148221033046416&key=f0a7f91912ae2b52e0700f73990eb321&libId=iwx018a701000n4o000DA1bhr14rgwlxii&loc=http%3A%2F%2Fforum.xda-developers.com%2Fv20%2Fdevelopment%2Fh918-recowvery-unlock-v20-root-shell-t3490594&v=1&out=http%3A%2F%2Ftool.lime.gdms.lge.com%2Fdn%2Fdownloader.dev%3FfileKey%3DUW00120120425&title=%5BH918%7CUS996%7CH830%5D%20recowvery%2C%20unlock%20your%20V20%E2%80%A6%20%7C%20LG%20V20&txt=http%3A%2F%2Ftool.lime.gdms.lge.com%2Fdn%2Fdow...%3DUW00120120425

• Mac Here

http://redirect.viglink.com/?format=go&jsonp=vglnk_148221033837117&key=f0a7f91912ae2b52e0700f73990eb321&libId=iwx018a701000n4o000DA1bhr14rgwlxii&loc=http%3A%2F%2Fforum.xda-developers.com%2Fv20%2Fdevelopment%2Fh918-recowvery-unlock-v20-root-shell-t3490594&v=1&out=http%3A%2F%2Ftool.lime.gdms.lge.com%2Fdn%2Fdownloader.dev%3FfileKey%3DUW00320110909&title=%5BH918%7CUS996%7CH830%5D%20recowvery%2C%20unlock%20your%20V20%E2%80%A6%20%7C%20LG%20V20&txt=http%3A%2F%2Ftool.lime.gdms.lge.com%2Fdn%2Fdow...%3DUW00320110909

• Adb and Fastboot also needed to unlock the bootloader. Here

http://forum.xda-developers.com/android/software/host-tools-t3402497

• Enable developer options on your LG V20 device.
• Go to Settings - About device - Software info - Build number.
• Tap seven (7) times until developer options enabled.
• Now, turn on OEM unlock
• Leave developer options and OEM unlock during using a custom ROM or recovery.
• Extract ADB and fastboot at the same folder on your computer. for example C:\adb
• Now, open command prompt from this folder, How to do it ?
• Press and hold shift key on keyboard, then right click mouse on empty space.
• Now, click Open command window here
• Then connect LG V20 device to the computer using USB cable, and select PTP Transfer Protocol mode.
• Now type the following command at command prompt.
• adb start-server
• This command will check your LG V20 to accept debugging authorization
• Once your LG V20 authorized, type the following command to reboot your device. It will reboot your device into fastboot mode
• adb reboot bootloader
• Once your device entering fastboot mode, now type the following command to check the connections between LG V20 and the computer.
• fastboot devices
• If you're the LG V20 (H918 and H830) user, type the following command below to unlock bootloader.

  

  unlock bootloader LG V20 - H918 & H830

• fastboot oem unlock
• Once this command send to your LG V20, it will wipe all data stored in internal memory and perform factory reset
• Now type the following command to check the bootloader status 
• fastboot oem device-info
• Then your screen should return with the result.

  

  device unlocked - LG V20

• Finish, Now your LG V20 is unlocked.