Works on both chipsets.. I saw this tip on the board so I decided to make a clear instruction note on how to use it.
Download QuickShortCutMaker from the Play Store:
Run the app:
Go to Call Settings
Then select the LAST:
Call Screening option should right after Call Screen Emergency and one up CAMERA
Click on TRY
Click on Top left menu ≡
Select Band Selection
Take a screenshot to make sure you can come back to factory settings in case you have issues.
Pick the band or bands you want, toggle the SELECTION button on the right up corner.
You are all set.
I suggest rebooting the phone but this is totally optional.
REMEMBER: YOU ARE DOING THIS AT YOUR OWN RISK.