[Q] Unable to unlock bootloader topic

Hi,
I tried to unlock my bootloader via flash tool, but for some reason, my rooting status (my bootloader) is unknown (before was unlockable). I relocked and unlocked it again but still no luck. I flashed the latest firmware with flashtool.. but my bootloader's status is still unknown. The device is rooted and verified. What i must to do to have back bootloader to unlockable?
Please help..