Do you mean you downloaded TMobile firmware? I've just done the same thing. I'm hoping, maybe grasping for any solution, to get better Tmobile service from this Note 8.Downloaded the att firmware that was on xda and it worked. Do now have the T-Mobile splash when booting and Wi-Fi calling is working now. Software version shows tmobile and att now. //uploads.tapatalk-cdn.com/20180320/90ec49dfd78bc8de6d2b3d5346666d30.jpg
I'm definitely in areas where this phone should pick up a T mobile signal and it is only getting ATT