So i have tried 3 different supreme pro plus's and its the same story.. i cut my tmobile sim card with my sim cutter.. installed with the gevey supreme.. the instruction screen came up.. following the instructions with dialing 112, airplane etc etc.. it goes to searching up top, there is a carrier menu in settings but just says searching, it seems like its working because the new voicemail popup comes on but it never connects.. no signal or anything... ugh this is frustrating!!!
Here's a good fix for you but it is totally up to you. Are you ready?
Throw away the Gevey Supreme sim and get a legit Gevey Ultra sim. The Gevey Supreme sims seem to be hit or miss. More miss than hit if you ask me. I have played with the Gevey Ultra sims for a good while now and so far haven't run into any major issues with it at all. Just my opinion though.