Asus ZenFone 2 bootloader gets unlocked
Another potential problem deals with the level of your knowledge. If you've never installed a custom ROM on your phone, a slight screw up could brick your handset and without warranty coverage, you're SOL. Another thing to consider is that once you install a ROM or root your phone, you no longer will receive OTA updates until you re-install Android.
If you feel the need to unlock your Asus ZoneFone 2, you can follow the instructions at the sourcelink. Again, if you don't know what you're doing, it might be best to leave your ZenFone 2 alone unless you're looking for a $300 paperweight.
source: XDA via AndroidCentral