How do I tell if iPhone 4 is Factory Unlocked

[jeff7602]

I am planning on buying an iPhone 4 off of Craigslist tomorrow. The owner says that he had AT&T do a factory unlock on it.

Is there a quick or easy way for me to tell if it's truly factory unlocked opposed to jailbroken or something else? I want to make sure that it's not going to be locked again if I need to update it or restore it.

I don't know that I'll have the chance to restore it right there while we are making the deal, so I am hoping there is another way that I can tell.

 

[alphaod]

Yeah there is a seller on ebay that sells unlocks. There is a tool on the page that let's you type in the IMEI and it will tell you if it's unlocked or not.

For example when I type in the IMEI for my iPhone 5 that I know is unlocked, it says it's unlocked whereas when I type in the IMEI for my iPhone, it says it's locked to AT&T.

Link:
http://www.ebay.com/itm/ATT-AT-T-UN...449?pt=LH_DefaultDomain_0&hash=item2ec2a01fe9

 

[stu.h]

Www.iphoneox.com

 

[AFDoc]

put a different sim in it and check it (not your carrier's sim)