How to unlock bootloader again on stock 6.0.1

hi guy i already unlock bootloader previously and installed many rom but later i fastboot flashed MM6.0.1 stock and locked the bootloader and it show status :2 , now i want to unlock the bootloader again and want to install twrp and roor the device on stock mm 6.0.1 pls help

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hi guy i already unlock bootloader previously and installed many rom but later i fastboot flashed MM6.0.1 stock and locked the bootloader and it show status :2 , now i want to unlock the bootloader again and want to install twrp and roor the device on stock mm 6.0.1 pls help

from xda-developers http://ift.tt/2c6IsMT
via IFTTT