Now that a Stock version of Android 6.0 Marshmallow has been posted for the LG G4 it would be nice if the phone's bootloader could be unlocked so you can take advantage. I kept my H815 review unit for months holding out hope that the bootloader would be unlockable. While several other variants were unlockable for some reason LG never made this one unlockable until now.
You can now unlock the bootloader of the South East Asia variant officially through their developer website. The website clearly states that unlocking your bootloader will void your warranty, unlocking may disable certain functions (ie Android Pay ect), unlocking your device might make it vulnerable, once unlocked you can not relock the bootloader. There is a full guide with downloads for unlocking the bootloader at the developer site link below.
via developers.lge.com