Why isn't my Unlocked GS4 going into roaming mode?

[ruffdeezy]

Unlocked GS4, roaming problem

Hi,
Have GS4 for 2 weeks now after iPhone since the beginning. Anyway, bought an unlocked one that is AT&T branded. I'm using it on the Fido network in Canada. There is no problems at all using it here. Only funny this is we call LTE just LTE not 4G LTE and 3G shows as just 4G on the phone but whatever.
I was in the USA today and on my iPhone it would automatically just switch to roam on AT&T after crossing the border, I always kept data roaming off. Today, my phone never switched onto AT&T, just stay on Fido with no signal. I left data roaming off to not get hit with any charges. Any idea why it wouldn't roam or is there some setting I'm missing?

regards

 

[Rukbat]

Re: Unlocked GS4, roaming problem

Wild guess (and that's all it is, so take it for what it's worth) - the SIM isn't set to roam on 2G. Fido would have to replace it with one that is. (As I said - just a wild guess.)

 

[ruffdeezy]

Re: Unlocked GS4, roaming problem

Sim came straight out of iPhone which worked

 

[Rukbat]

Re: Unlocked GS4, roaming problem

Still a possibility, though. The SIM works on an iPhone, that doesn't mean it will perform the same in an S4. (Sprint claims that it can't supply SIMs for the Nexus 6, because the ones for the iPhone won't work, even though they're the right size.)