Invalid Sim Card Sprint. Invalid sim card errors, then falls back to tmobile. 1) for sprint phones built prior to february.
I bought my x4 about a month ago from google fi, and it has the same problem switching to sprint. Go to doctorsim.com from a web browser. Locate the sim card tray on your device.
In case anyone is jumping to the bottom of this thread, this is exactly what you need to do if you are getting invalid sim card on a newly purchased boost mobile phone with the 5g sim card activation kit.
In case anyone is jumping to the bottom of this thread, this is exactly what you need to do if you are getting invalid sim card on a newly purchased boost mobile phone with the 5g sim card activation kit. If your phone shows invalid sim it means it is relocked, you can unlock again same methods mentioned. Go to doctorsim.com from a web browser. Luckily tmobile is the best service in.