When buying a phone directly from carrier and paying for your two-year contract you don’t have to worry whether the phone has a clean or bad ESN (MEID) because you’d be the first and original owner. But if you’re buying a phone from eBay, the web, or another person then it’s really important for you to know if the phone has a bad ESN or the ESN is clean. ESN is only for CDMA carriers like Sprint and Verizon, so you if have a GSM carrier like AT&T, then you don’t have to worry about.
Ever since Verizon and Sprint got the iPhone last year, when you try to buy an iPhone on eBay, Craigslist or another place you’d notice that it will have many iPhone listed as bad ESN. This can be good or bad. Phones with bad ESN are typically sold with a cheaper price. The problem is that it cannot be activated on the original network if it has a bad ESN. Here are some common questions people have about the ESN (MEID) of iPhones.
What is an iPhone with bad ESN?
When a phone is listed as bad ESN, it means that the original owner reported the iPhone as lost/stolen, activated on another account, or owner could not keep up with the contract payments. If the ESN is clean, it means that you will be able to activated on the carrier with no problem.
Can a phone with bad ESN be activated on another carrier?Â
Yes, phones with bad ESN can be activated on another carrier if that CDMA carrier allows unbranded phones in their network. Many CDMA companies like Sprint and Verizon will not accept  phones that are non branded to them. If you unlock the SIM slot of the iPhone 4S using third-party tools like Gevey SIM then, even if the phone has a bad ESN, it will work on any GSM networks including GSM network in the United States like AT&T or T-Mobile.
Will Sprint, Verizon take my phone away if they notice it has a bad ESN?
No, no carrier will take the phone away from you if you try to activate a phone with bad ESN (MEID).
What can can a phone with bad ESN do?
As mentioned above, you can still activate a phone with bad ESN with another different carrier if the phone GSM side is unlocked or if another CDMA network allows you to activate phones from other carriers. But the phone can still be used as a normal phone (camera, internet, apps should still work fine).
So buying a phone with bad ESN is not always a bad idea if you know what you’re doing. Bad ESN phones will always be sold for a cheaper price and by knowing what yo can do and can’t do has its advantages.