Launch DC-Unlocker software
Select manufacturer: ZTE modems, model leave Auto detect (recommended).
Press detect button (Big magnifying glass)
Wait for device to be detected
Open Server tab, enter username and password that you received after credits purchase. Click "Check login" (you can buy credits here www.dc-unlocker.com/buy).
If DC-Unlocker/Vygis/Rocker/Infinity dongle is connected, do not enter username and password, only click "Check login"
Open Unlocking tab, click “Unlock”
Wait for device to be unlocked. After you see a message that modem is successfully unlocked, disconnect device from USB cable, turn it off, remove battery from it for 5 seconds then place it back, now your device is unlocked