Question

T-Mobile says my phone is locked - is it?


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I bought a Sony Xperia 10 III. I have a prepaid account for $15/month. I experiment with phones so I have other phones that I can put my SIM card into and they work. This new (to me) Xperia is off EBay. The seller says it is unlocked. Poking around on various websites seems to indicate that it is unlocked. When I check the IMEI using the T-Mobile BOYP website I get

This device is fully compatible with T-Mobile’s network technology.

  • This device is fully compatible with T-Mobile’s network technology.
  • This device is not blocked from use on our network.
  • Your phone uses a physical SIM card to hold wireless account information.

When I use the Device information in the account for the block check, it says device not found.

My SIM doesn’t work in this Xperia. It shows T-Mobile and if I turn off the automatic network selection I can see the list of T-Mobile networks, but it won’t connect.

I have a bunch of old SIM cards. When I put a used Google Fi card in, it says I can use it but not for voice and text (well, it was used before in a different phone and cancelled). Same with a used AT&T GSM card.

I’ve called support a couple of times and they tell me that the phone is locked. Is it really?

I’m contacting the seller but haven’t heard back yet.


10 replies

Userlevel 7
Badge +15

For a device to be usable on the T-Mobile USA network, it must be compatible with T-Mobile's VoLTE to be able to make calls and texts.  3G has been discontinued for quite a while now and their device checker hasn't been updated to reflect that and even band compatibility does not mean VoLTE is compatible.  What model Xperia 3 do you have?  

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It's an Xperia 10, sub-model III (3), not an Xperia 3.

Userlevel 7
Badge +14

Have you tried checking the imei number on Swappa?

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I don't see where to do that there. Is it part of selling?

Userlevel 7
Badge +15

I don't see where to do that there. Is it part of selling?

swappa.com/IMEI

That will make sure the device isn't blacklisted.  

Edit:  Checking the device compatibility.  I am going to say that because it is missing most of the heavily used T-Mobile bands, that it is more than likely not VoLTE compatible, even if you are in am area with a supported band for coverage. 

 

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It has to be lower case in that swappa URL, swappa.com/imei, but that got me going in the right direction. Thank you. The phone is “allowed” (for sale, so it’s not blacklisted).

Yes, the bands are a concern. It’s a known issue, but people who use it say that T-Mobile is the best network to use for this purpose (okay, I’m being vague - it’s supposed to be the best phone/provider combo to run Sailfish OS in the US).

T-Mobile support has told me it’s carrier locked. They don’t tell me who it is locked by. If I were not connecting because of the bands, would that look like a carrier lock? Wouldn’t support just tell me that the phone is not compatible? They have directly told me that the phone *is* compatible with their network and that simply putting my T-Mobile SIM into the phone should work.

At this point, I’m trying to confirm that it is carrier locked and then fine out who it is carrier locked to. I will understand if this is too off-topic for these T-Mobile discussions.

Userlevel 7
Badge +15

Prepaid support could use a lot of improvements.  Usually carrier locked devices tell you that the operator or network is not supported when the device detects a SIM that isn't from a carrier the device is SIM locked to.  If you were somewhere that you know had service on band 41 for T-Mobile as an example, which has pretty much only been deployed for 5G on most regions.  That would help rule out or confirm if the device is SIM locked.

Userlevel 7
Badge +14

Hey there! 

I wanted to share a little good news and ask a question. 

The IMEI checker available on our website does now check for the VoLTE compatibility, so if you enter the IMEI of a phone that does not have VoLTE, it will tell you it is not compatible with our network. 

@lsitongia When did you get your sim card? In 2020, a new sim card standard called R15 was launched. Most phones and old sim cards still worked, but new phones with 5G required the new R15 sim cards. It looks like Sony Xperia10 III was released in 2021. If you have a previous sim card model, it could explain why it works in other phones but not this one.  

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That’s a great line of thinking, but I got the SIM in 2022. Thank you for telling me about that factor.

Userlevel 7
Badge +14

Hmm. This is a head scratcher. Syaoran is right about the phone usually saying that the network is unsupported if the device is locked to a different carrier. The IMEI checker usually shows an error if the phone is blocklisted. Everything seems to be good, but the phone still does not want to connect. 

The last thing I would suggest is to check/update the APN settings to make sure the phone is fully set up to work with our network and data. BYOD T-Mobile data & APN settings.

Unfortunately, there isn't really a way to guarantee that every phone will work with our network and this phone may be one of the anomalies that sadly won’t. You put in a lot of effort, so kudos to your diligence. 😁

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