Unlock a Virgin Mobile USA iPhone 4s -- worthwhile? I have an iPhone 4s that works with Virgin Mobile USA. Since carriers must unlock phones now I'm wondering about unlocking this one. But I haven't been able to determine if it would actually be worthwhile. Specifically, whether I'd be able to use the phone with a different carrier.

The phone is an iPhone 4s, marked on the back as an A1387, and identifies itself in settings as an MD236LL/A. This is a CDMA refurb model, obtained from an Apple store after the original phone got dropped in a puddle.

What I'd like to do: (a) use the phone with some other US-based carrier while at home, and (b) when traveling outside the USA, use the phone with a local SIM and GSM network.

I've tried searching for unlocking info but I'm getting conflicting answers about whether either of the above are possible:


Some sites say that since the 4s is a "world" phone that after unlocking it would work on both domestic (US) GSM networks as well as CDMA networks like Verizon.
Some sites say that although it's a "world" phone, it's tied to CDMA when in the USA. While traveling it would work with a GSM network using local SIM but in the USA it could not use a GSM network.
Still others say that "world" means nothing here, that it's strictly CDMA and can't use GSM at all.


Can anyone clear this up? I know I can legally get the phone unlocked, but would doing so get me either of the things mentioned above? Virgin Mobile USA's site isn't helping me. They have a chart listing types of unlocks for different phones, but from past experience with them I pretty much assume they're either lying or just plain wrong about most things.
iPhone 4s, both the CDMA and GSM models, has GSM hardware built-in. The only difference between the two models is whether the device supports CDMA, and in that case, which network it supports. A device sold by Virgin Mobile, which piggybacks on Sprint's network, may work in CDMA mode on the Sprint network once unlocked, though you would need to confirm this with Sprint. It cannot be used on Verizon's network. In GSM mode, it can be used outside the US on essentially any network. It cannot be used on US-based GSM carriers (T-Mobile/AT&amp;T).

The iPhone 4 CDMA model (sold at Verizon) was not compatible with any GSM network, US-based or otherwise. That may be where the confusion lies.