No need credits no need usb cable
Just connect to WiFi and follow the instractions
1) Make sure you have an active data connection via 3G/4G/LTE or Wi-Fi.
2) From the Application list, tap Device Unlock. (Note: The application may be located in the MetroPCS folder.)
3) Choose the Permanent Unlock type:
If successful, restart the device to apply the settings.
all instruction’s credit goes tohttp://www.howardforums.com/showthre…ia-Android-App
Press thanks button if my post will be help full