Here is a new IPTV file with some american channels added. I tested my self and its a go.

Delete the actual list (If you want to keep any channel that you have now write the name, and the URL address) . Go to IPTV , hit Edit red boton, hit Delete blue boton , hit delete all yellow boton. Now the list is empty. Load the new list in your USB. Go to IPTV hit Edit red boton, hit Scan USB URL green boton, it will automatically load your new list.

[Only registered and activated users can see links. ]

I havent try just scanning the USB new URL list without deleting the actual. You may want to try that.

Finally if you erase the old one go to edit red boton and Add the channels and the URL you have before.