I just purchased a GSM unlocked Samsung s10e. The phone was orginally a T-Mobile phone but my SIM is for AT&T. I've manually changed the carrier to fit my SIM card (Settings>Connections>Mobile Networks>Network Operators>Search Now>AT&T). However, when I turn the phone off and on, it reverts back to T-Mobile. How can I get this to stay on AT&T by default?
Because your device was originally sold from T-Mobile it will unfortunately stay with T-Mobile bootup animation & bloatware unless you decide you want to learn to flash U1 firmware. Which this process can be learned by researching on sammobile.com. Good Luck!
