Can someone please explain what is a bad ESN phone?

celo48

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Original poster
Apr 9, 2010
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As far as I understand, the phone is financed and not paid. Then the carrier cuts the service to that phone.

If the carrier say Sprint does not report it to others, then you can use this phone with AT&T. Yes?

How about using a Sprint or Verizon iPhone internationally? I assume AT&T or T-Mobile cannot be used since the GSM is locked but with Sprint or Verizon the GSM is not locked, only CDMA.

Any comments? Thanks.
 

Applejuiced

macrumors Westmere
Apr 16, 2008
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At the iPhone hacks section.
If its unlocked but with bad ESN then it will work on GSM carriers outside the US.
If its ESN/IMEI blacklisted sometimes that block doesnt carry to all US carriers. So if its blacklisted at AT&T it could still work at Tmobile etc..
You'll have to test it in person to make sure though.
 

celo48

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Original poster
Apr 9, 2010
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If its unlocked but with bad ESN then it will work on GSM carriers outside the US.
If its ESN/IMEI blacklisted sometimes that block doesnt carry to all US carriers. So if its blacklisted at AT&T it could still work at Tmobile etc..
You'll have to test it in person to make sure though.
Thanks. So say I get a Sprint phone with bad ESN. Locked to Sprint. Wouldn't work with AT&T or overseas carrier since these phones are CDMA but the phones GSM section is actually not locked from Apple. No?
 

Applejuiced

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Apr 16, 2008
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Yes, if its locked to sprint it and has bad ESN it will not work anywhere. Not in the US or outside the US. Nothing.
If its an unlocked Sprint iphone with bad ESN it might work on some US carriers and all international GSM carriers outside the US.
Sprint iphones have GSM enabled also so if its unlocked it will work overseas with other gsm carriers.


Thanks. So say I get a Sprint phone with bad ESN. Locked to Sprint. Wouldn't work with AT&T or overseas carrier since these phones are CDMA but the phones GSM section is actually not locked from Apple. No?
 

celo48

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Original poster
Apr 9, 2010
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Sprint iphones have GSM enabled also so if its unlocked it will work overseas with other gsm carriers.
That's what I was trying to figure out.

I can buy a bad ESN Sprint phone that is LOCKED to Sprint BUT will work with GSM carriers? No? Or you are still saying it must be unlocked regardless.

Because I remember people buying Verizon/Sprint phones but was also able to use them with AT&T/T-Mobile since Apple had the GSM part unlocked from the factory.
 

celo48

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Original poster
Apr 9, 2010
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No, Sprint iphones do not come unlocked like Verizon iphones.
You cannot use them on any other carrier unless Sprint approves and submits it to get unlocked.
OK, so if I buy a LOCKED bad ESN Verizon, it would work or same thing like Sprint?

Sorry for multiple questions and thanks for your patience :)
 

nburwell

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May 6, 2008
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A couple years ago, I unknowingly purchased a bad ESN Verizon iPhone 6 from Swappa. I was with AT&T at the time, so the phone worked without any issues. When I went to sell the phone, the buyer (who was using it on Verizon) informed me a couple months later that Verizon had blacklisted the phone.

After the process was all said and done, I refunded the buyer his money back and filed a dispute with the original seller. Even after I got the phone back, I popped my AT&T SIM card in and everything still worked. That doesn't mean that it would always work with AT&T though, so YMMV.
 

eyoungren

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Aug 31, 2011
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OK, so if I buy a LOCKED bad ESN Verizon, it would work or same thing like Sprint?

Sorry for multiple questions and thanks for your patience :)
You have to understand the concept of LOCKED.

LOCKED means only able to be used on the network the phone was intended for.

UNLOCKED means being able to be used on any network that the phone supports.

Verizon LTE capable phones are always unlocked because they have to abide by an agreement with the FCC. Sprint doesn't have that agreement so they lock their phones.

Bad ESN is entirely separate. If a phone is UNLOCKED then a bad ESN may prevent it from being used on a particular network because it's blacklisted. But a locked phone with a bad ESN already has two strikes against it.
 
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celo48

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Original poster
Apr 9, 2010
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You have to understand the concept of LOCKED.

LOCKED means only able to be used on the network the phone was intended for.

UNLOCKED means being able to be used on any network that the phone supports.

Verizon LTE capable phones are always unlocked because they have to abide by an agreement with the FCC. Sprint doesn't have that agreement so they lock their phones.

Bad ESN is entirely separate. If a phone is UNLOCKED then a bad ESN may prevent it from being used on a particular network because it's blacklisted. But a locked phone with a bad ESN already has two strikes against it.
Thanks!

No, I know what a locked/unlocked mean.

So, if I get a Verizon with bad ESN, I am good since Verizon cannot lock the GSM part of the phone. That's what I want to know now :)
 

Applejuiced

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Apr 16, 2008
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At the iPhone hacks section.
No, if you buy a locked sprint phone with bad esn it will not work anywhere.
If you buy a verizon bad ESN iphone it might work on some gsm carriers in the US and all GSM carriers outside the US.

OK, so if I buy a LOCKED bad ESN Verizon, it would work or same thing like Sprint?

Sorry for multiple questions and thanks for your patience :)
[doublepost=1508520643][/doublepost]Yep, its mission impossible with Sprint. :D

Right!

And just TRY and get Sprint to unlock a phone with a bad ESN!!!

Getting them to unlock a phone in good status that meets their unlock requirements is hard enough.
 
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celo48

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Original poster
Apr 9, 2010
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No, if you buy a locked sprint phone with bad esn it will not work anywhere.
If you buy a verizon bad ESN iphone it might work on some gsm carriers in the US and all GSM carriers outside the US.
Yes, this! :) Thanks. So, Verizon is the ONLY carrier that can work on other GSM based networks although it has a bad ESN. Verizon will NOT work with Sprint/Virgin or any other CDMA based network carriers.
 
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fischersd

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Oct 23, 2014
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Yes, this! :) Thanks. So, Verizon is the ONLY carrier that can work on other GSM based networks although it has a bad ESN. Verizon will NOT work with Sprint/Virgin or any other CDMA based network carriers.
Keep in mind, it depends on why the ESN is flagged as bad. If it's stolen, there's no reason why Verizon can't report the IMEI to the GSMA so it's blacklisted globally. And they just might count a phone that wasn't paid off as stolen.

There's only a handful of CDMA carriers in the world - most have shut down their CDMA towers, so CDMA roaming is virtually non-existent.