Go to Mi Unlocker website and click on unlock now. Login into the website with your Xiaomi account credentials and submit your request. Then, you will receive a text message (takes 3 days to 21 days).

Download and Extract the Mi Flash Unlock tool on the PC. Upon extracting, open MiFlashUnlock.exe file from the folder and click Agree on the disclaimer page.

HTC has rolled out their unlockable bootloader for the first of three phones, the HTC Sensation.