IPhone – Buying iphone connected to a carrier for wifi

Yes, for Verizon phones in the US, neither the month-to-month contract (unsubsidized) phones (when they become available) nor the subsidized phones are in any way carrier-locked.

I tested this by establishing AT&T service on my subsidized iPhone 5 before I did anything with the Verizon side of things and it has worked with both data and cellular provisioning on the nano-SIM from AT&T.

The Apple LTE page will guide you to know which frequencies are available for which model of iPhone 5. The model of each phone is conveniently printed on the back plate of each device.

The carrier you intend to get service from is in the best position to guide you in picking a US model to import, but Apple's documentation show no difference in the GSM 3G capabilities of any of the three phones available at launch, namely the A1428 (GSM), A1429 (CDMA or GSM).

If re-setting your network connections didn't help, it could be a hardware problem.

Depending on when it was made, it could be that your WiFi chip inside the phone has pulled (or, rather, is in the process of pulling) off of the circuit board. Late 4S models also had this problem, and here's how it manifests (progressively):

• Very slow speeds / drops connection to the network intermittently
• Stops seeing most (or all) networks, but the WiFi button still works, it's not grayed out
• Can't turn WiFi on at all, the button is grayed out in the settings menu - but the WiFi button in the control center might appear to work.

If your phone is under warranty, then take it to an Apple store and have them replace it. Believe it or not, the repair is quite easy, so if it's out of warranty and you know of a place that fixes phones, they've probably got some spare chips and won't charge too much. Apparently, it's a manufacturing defect, so a repaired phone fixed by someone that knows their stuff could last quite some time.

This has only been a problem with certain 4S and 5 models, you'll see a bunch of people reporting it if you search for something like "iPhone in freezer" - because (believe it or not), putting your phone in a Ziplock and then freezing it for a few minutes has been known to fix the problem for a short time (though I don't recommend doing this).

AFAIK, this isn't an issue with 5C, 5S or recently (as in the last year) manufactured iPhone 5 units. Could be a good opportunity to upgrade, even if you manage to get it fixed.