Originally Posted by
allset2travel
New to TMO ... switched to TMO with my unlocked Samsung GS4 phone. On a recent trip to China ... phone would try to reboot itself and got hung up at the point where the ATT globe showed up. This went on many many times. Later on in Seoul, S. Korea. Same thing happened.
Now I have returned home, everything seemed to be working fine so far (first day). Was I suppose to change some settings while in China and S. Korea? Please advise. I want to get a little background to the problem before I called TMO. Thanks.
Is your GS4's firmware up-to-date as they should? For your next trip (if returning to same places again) - check your APN settings, devices running Androids on 4G LTE might want to try using fast.t-mobile.com, instead of the one with epc.xxxx while abroad. Also, try toggling network type between LTE and 3G - power cycle/reboot your GS4 and see if it will register automatically on the local partner's system.
While taxing along the runway @ICN, switched on my Nexus 5 and within moments, got the Free T-Mo Msg: Welcome to South Korea, etc. on the device. Nieces that were traveling with us initially had trouble with data on their iPhone 6+ (Simple Choice Plan, Family Share ones) so they placed a call back free to the US & spoke to T-Mo (+1 505-008-3793) and had that resolved/fixed promptly.
Just about everybody in Seoul is walking around with one of the Samsung's phabet so it's hard to imagine that yours were acting up - but, I did have a saved note on SKTel's network - "South Korea does not have GSM, they do have UMTS-2100. So, you need a phone that has UMTS/3G/HSPA+ 2100."
Perhaps that explained my unlocked iPhone5s (from VZW) registered more easily on SK's system without playing with the APN, etc. We were also in Taiwan for a week on a group's island tour & had no issues at all - but, didn't travel to China so ...