You can still unlock the boot-loader even though ASUS has disabled the server for the official unlocking method. Here's how.Gather (and extract) the files needed.A known-to-work firmware to start with, ASUS_ROG2_ZS660KL_QPST_Firmware.zip. Get it from this XDA thread. Henceforth referred to as 'firmware archive'.The special sauce to unlock the bootloader, ASUS_ROG2_ZS660KL_UnlockBootloader.zip. Get it from this XDA thread...Read more