Official LG G5 H850 Bootloader Unlock

The European H850 can now be officially unlocked through LG's developer unlock program page.

Yes, only the European version. Your H850 is from the Middle East? Won't work. You have an AT&T G5? That's not an H850, move along.

LG Developer Unlock Site Here

Prerequisites:
1. European LG G5 H850
2. Computer w/ADB & Fastboot. ADB/Fastboot for Windows here. ADB/Fastboot for Linux/OS X here.
3. Basic knowledge of ADB, Fastboot and Windows command prompt or Linux/OS X terminal.
4. Device IMEI. This 15-digit code can be found on your box, the back of the phone or by dialing *#06# 
5. LG developer account (free, click here then click sign in at the top of the page to make an account.)


Directions:
LG's official bootloader unlock directions can be found in the big link at the top of the page.. 
but I've still rewritten the steps out below while adding some for root and TWRP. 

1. Enable USB-Debugging on your phone. USB-Debugging is required for the commands “adb” and “fastboot” to work. To enable USB-Debugging, go to Settings >> About phone >> Software info and tap Build number 7 times. Return to the previous screen, select Developer options and enable USB-Debugging.

2. Enable OEM unlock on your phone. Activating the "Enable OEM unlock" is necessary for the bootloader unlock. To enable OEM unlock, go to Settings >> Developer options and check Enable OEM unlock.

3. Open CommandPrompt or Terminal and enter the following ADB command to reboot into the bootloader:

Code:

adb reboot bootloader

If ADB is not detecting your device try switching your phone's USB mode from Charging to MTP or PTP. 

4. Once in the bootloader, use the following fastboot command to obtain Device ID:

Code:

fastboot oem device-id

Fastboot command will return a string. This is the Device ID which is needed to generate your unique unlock key.

Example :

Code:

$ fastboot oem device-id
(bootloader)-----------------------------------------------------------------
(bootloader) Device-ID
(bootloader) CD58B679A38D6B613ED518F37A05E013
(bootloader) F93190BD558261DBBC5584E8EF8789B1
(bootloader)-----------------------------------------------------------------

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:

CD58B679A38D6B613ED518F37A05E013F93190BD558261DBBC 5584E8EF8789B1

5. Copy Device ID and IMEI into the LG developers unlock site and hit the confirm button. In a few moments the unlock.bin will be emailed to you. Download unlock.bin to computer.

6. While the phone is still in fastboot enter the following command to unlock the bootloader:
This will unlock your phone AND factory reset your device wiping all data!

Code:

fastboot flash unlock unlock.bin

7. You can now reboot the phone and boot into your unlocked device! Enter:

Code:

fastboot reboot

8. Want root or TWRP? Before moving forward I suggest getting a microSD card and putting the SuperSu 2.65 zip on there. Do not set the external SD up as adoptive storage. Download this TWRP image too.

Reboot back into the bootloader (you'll have to first re-enable USB debugging):

Code:

adb reboot bootloader

9. Flash TWRP:

Code:

fastboot flash recovery twrp-3.0.2-0-h850.img

For TWRP to "stick" you must first boot directly into TWRP and not back into Android, until after flashing the SuperSU zip. 
After flashing TWRP unplug the USB cable and pull the battery. Plug battery back in then boot into recovery which should hopefully load TWRP.
To boot into recovery:
a. Using 2 hands.. use one hand/finger to press/hold volume down.. and use the other hand for the power button. Press n hold both buttons.
b. As soon as you see the LG logo on the screen.. let go of the power button then quickly press it again (never letting go of volume down).
c. Keep holding until you see the Factory Reset screen. Click thru the factory reset screens.. Yes.. Yes...

10. You will not be able to decrypt your internal data while in TWRP (unless performing a full /data wipe in TWRP and you will lose encryption!) but you can manually mount your external SD card to view the SuperSu zip. Feel free to back up first.. but otherwise.. time to install SuperSu. Click the Install button and navigate to the external_sd, select the SuperSu zip then swipe to install. Now you're rooted and TWRP'd! Reboot into system...

Have fun and be careful.