Originally Posted by soyimparable
I have the galaxy s5 from t-mobile SM-G900T , but I live in Mexico and I have a bad network signal where I live soo I can change the modem for the SM-G900M
If you want to update a modem, you should stick to the original carrier that the phone was manufactured for no matter what network you plan to use it on. Remember phones work & roam on other networks. Trying to flash a modem from a different variant will typically be refused by Odin and may brick your phone as well.
So stick to TMobile modems for your 900T. If the 900T is at all compatible with your Mexican network to start with, then the updated TMB modem will work fine.