Install required drivers to ensure the device is detected in DC Unlocker
In the text field in DC Unlocker, Go to the last line and copy paste the lines down below depending on what band you want to lock it to.
The setting sometimes persists across reboots, Sometimes it doesn't.
AT^SYSCFGEX=“03”,3FFFFFFF,1,2,4,,
AT^SYSCFGEX=“03”,3FFFFFFF,1,2,8000000000,,