iPhone 5s, iOS 12.1.4
We're from the US, and now traveling in New Zealand. Our US cell provider is MVNO Ting, on our phones using Sprint's CDMA network. Overseas in GSM territory, the phones connect through various local GSM providers. My iPhone SE does this seamlessly.
My wife's iPhone 5s, however, is extremely slow to connect to the local networks, and now and again spontaneously disconnects. This isn't due to signal strength issues, as it's happening here in Wanaka, a sizeable town with excellent coverage...but only to her phone; mine connects immediately and stays connected.
I've updated the subscriber settings and done a service update. Performance improved, but it still does those bad things at irregular intervals.
Seems like I've done all I can sofware-wise while we're away from home. I could do a complete wipe-and-restore, but don't want to try that while we're still on the road.
My question is: have I run up against a hardware issue?