Question

Unlocked s21 Ultra showing as "Unknown Device" and not supporting 5G or Extended Range LTE on My Mobile account


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I just bought an unlocked S21 Ultra directly from Samsung.  It works great, including the tmobile voicemail app and RCS through the Google messages app.  It says I’m connected to 5G on the phone, and I get 150+mbps download from home on speedtest.net

The problem is that the tmobile account website shows this:

The problems with this is:

  1. Most important: I have free phone repair insurance through my Uber Visa Signature credit card.  In the past, when I filed a claim, they required a screenshot of the account to show that I have the device I’m filing a claim for on the tmobile account that I pay monthly through my credit card.  I would have issues proving that I have an S21 Ultra on my tmobile account if it says “unknown device:”
  2. I’m worried I’m not getting the best speeds or roaming experience if I were to take a road trip in a rural setting.  150mbps+ from home is good enough in the major city that I live in, and I’m sure it’ll be better if I get closer to the tmobile cell phone tower which is 3 blocks away.

How do I get this phone to show as “Samsung S21 Ultra” instead of “unknown device”?  I don’t see any option online to specify this.


45 replies

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I just bought an unlocked S21 Ultra directly from Samsung.  It works great, including the tmobile voicemail app and RCS through the Google messages app.  It says I’m connected to 5G on the phone, and I get 150+mbps download from home on speedtest.net

The problem is that the tmobile account website shows this:

The problems with this is:

  1. Most important: I have free phone repair insurance through my Uber Visa Signature credit card.  In the past, when I filed a claim, they required a screenshot of the account to show that I have the device I’m filing a claim for on the tmobile account that I pay monthly through my credit card.  I would have issues proving that I have an S21 Ultra on my tmobile account if it says “unknown device:”
  2. I’m worried I’m not getting the best speeds or roaming experience if I were to take a road trip in a rural setting.  150mbps+ from home is good enough in the major city that I live in, and I’m sure it’ll be better if I get closer to the tmobile cell phone tower which is 3 blocks away.

How do I get this phone to show as “Samsung S21 Ultra” instead of “unknown device”?  I don’t see any option online to specify this.

Not only that, but in areas covered by T-Mobile’s partners you will have no service. This happened to my wife and me. Galaxy Note 20 ultra 5g and Galaxy S20 from samsung. We had no service in Clarksburg WV, when we contacted T-Mobile we were told it’s because our devices were not purchased from T-Mobile, and as such are not allowed to roam on the US Cellular network where US Cellular provides domestic coverage for them. Just be aware.

Userlevel 7
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BYOD devices don't usually work for domestic roaming on T-Mobile due to the device not being a T-Mobile or US Cellular device in the case of West Virginia.  The device showing as an unknown device is normal for any device not sold to you by T-Mobile. 

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Not having the IMEI number is a bad excuse. I had to give it to them when I switched my unlocked S20Ultra from Verizon to TMobile. They sent me a new sim card for my wife and I which she has an unlocked iPhone she bought from Apple directly and after we were activated, it shows mine as unknown and hers as an iphone but they were both unlocked BYOD coming from another carrier. So why can't they just manually input the number when you give it to them. Sounds like just laziness. BTW my phone works great. It's in the 5G and even though the coverage has bit or miss issues (which I confirmed they were working on the network in that area) everything works great except the visual voicemail. I still can't get the default disabled and just use the TMobile one as a standalone. A little annoying. 

Hello to All,

I’m joining the Unknown Device list.  I purchased a brand-new Galaxy S21+ 5G 256GB DSDS Unlocked International phone that is 100% T-Mobile compatible.  I detected two issues:

  1.  The Unknown device status - My phone and yours are not in their network DB.  Even though a SIM can be installed and activated, and we still get billed and must pay, but the network doesn’t really know we are out there.  T-Mobile needs to cleanup their process to deal with BYOD - locked/unlocked device by gathering the requisite data: device, Serial N., EMEIs, and Freq Bands, etc. for entry into the network DB that runs things.
  2. My phone is now network locked after the T-Mobile SIM was installed.  I’ve been told it’s going to take 72+ hours to obtain the unlock code.  However, I have a DSDS (Dual Nano-SIM) phone and both of my EMEI numbers are valid, not blacklisted, and are NOT in the T-Mobile Network DB; and are NOT in the network DB, so that they can pull up my data based on my EMEI numbers.

Note:  I manage a complex NMS system for a large food supply shop, and when new IT staff join, they get admin level credentials and automatically gain access to the NMS system that monitors servers, WAN link, UPS, switches, etc.  So, when checking the DB for them via the NMS GUI, they aren’t there, but if I access the records at the SQL query level, guess what they are there.  So, to correct the issues, I must advise them that an acct issue is present, delete their acct, and add them with a more restrictive policy to the NMS system via the GUI.  Now the system is fully aware of them.

 

Sorry for the long story, but to correct this issue, many users may end up in the same predicament that my IT staff deal with and may lose cellular service while T-Mobile is making these changes.  You can’t have duplicate records present.

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How did your phone get locked into T-Mobile just by putting in their SIM card. I ordered one from them and put it in and after a quick update my phone shows it's on their network but it's not locked. I can easily swap my SIM card. Plus when I had issues connecting I have them my IMEI number so they have it but it still does not show any info. But my wife's iPhobe does and both our phones (S20ULTRA for me and iPhone XS for her) were bought unlocked directly through the manufacture and we're initially on Verizon for 2 years before we switched to TMO. So there no rhyme or reason here. 

On my phone, I can initiate a SIM Lock (haven't. cuz the T-Mobile is in slot 1), which is at a phone level, so the SIM can't be used in another phone or a 2nd SIM slot with a different EMEI No.

 

However, T-Mobile has applied a network SIM Lock on the SIM/EMEI in my slot 1.  I have a DSDS Dual Nano-SIM phone.

 The fix is a bit complicated, since I am somewhat on T-Moblie, but not Identifiable in their DB.

 

Very similar to my NMS acct issue where the IT staffer had access, and could add/delete/modify devices in the NMS, but from the GUI app, you couldn't find them at all.

 

T-Mobile needs to update their DB.  They're a global carrier, and have the resources to pull it off.

 

Another issue I have noticed on the unlocked versions is RCS doesn't work with Samsung messages app. Workaround is moving to Google messages app but still 

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I've got the same problem as I have in the past. 

Just to clarify we're talking about official  USA Samsung T-Mobile devices purchased in the USA from vendors other than T-Mobile directly and not dual sim international Samsung devices.

 

I purchased a T-Mobile Samsung S21U from Best Buy USA. It is not recognized by T-Mobile because the IMEI number is not in their system. 

 

Now this is a major problem for me because the IMEI needs to be in T-Mobiles system for a sim unlock request to be fulfilled. 

I had a similar issue in the past with T-Mobile Samsung devices bought from Samsung directly. T-Mobile claim they can't sim unlock the device because it's not in their system.  

I have already contacted T-Force via Twitter but have been told to wait at least 14 days to get a response. We'll see. 

 

Userlevel 6
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if its a TMO variant then it should already be in their system..it was branded for them after all..which if memory serves if you purchased it from another vendor it must be on their network for a certain amount of days before it can be unlocked by TMO. 40 days i believe for Post paid and a year for Pre paid or something along those lines.

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if its a TMO variant then it should already be in their system..it was branded for them after all..which if memory serves if you purchased it from another vendor it must be on their network for a certain amount of days before it can be unlocked by TMO. 40 days i believe for Post paid and a year for Pre paid or something along those lines.

It should be in their system , but it isn't in their system hence the post.  Similar to when I purchased a T-Mobile device from Samsung directly. 

I have the same issue, my Samsung S21 Ultra is showing up as unknown device. I was looking into Xfinity Mobile since Verizon has better coverage in my neighborhood but they’re telling me my device is not compatible. It can’t be true since Xfinity sells the S21 Ultra. Not sure exactly, but I’m thinking it’s related to this issue, which is frustrating.

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I have the same issue, my Samsung S21 Ultra is showing up as unknown device. I was looking into Xfinity Mobile since Verizon has better coverage in my neighborhood but they’re telling me my device is not compatible. It can’t be true since Xfinity sells the S21 Ultra. Not sure exactly, but I’m thinking it’s related to this issue, which is frustrating.

 

Is your device a T-Mobile branded device and if so where was it bought from ? 

 

It it's a T-Mobile branded device bought from any authorized dealer other than TMobile directly then  it's  the same issue as me. 

Because T-Mobile state that they can't process sim unlock requests because the IMEI isn't recognized due to it not being in their system. 

Ive already filed a complaint to the FCC. Since it's unacceptable that a phone should remain sim locked with no avenue to get it unlocked due to system limitations.

 

I bought it at Best Buy. Guess I should have known :(

I also wasted hours with T-mobile tech help with the same response from them... They found the problem and said it would get corrected within 48 - 72 hours. I was then told that they would follow up with me. Never happened. What is surprising, my wife's unlocked IPhone 12 pro and my IPad show up as identified since T-mobile has more Samsung galaxy users than Verizon and AT&T. You would think Both Samsung and T-mobile would make sure everything worked correctly. 

 
 
Userlevel 1

I brought over a Samsung S10e from Verizon and a new unlocked S21 Ultra (bought from Samsung).

The 10e is identified correctly, the Ultra is unknown.  So I don’t know if porting brought over info from Verizon or it’s just somewhat random.   Of course, about from identifying the model, little of the other stuff like checking lock status, works

Bought a t-mobile branded Z-flip 3 from Samsung. Getting T-mobile updates and T-mobile crapware installed but the device is Network locked to T-mobile and showing as an unknown device on my dashboard. This is really bad customer service.

I’m about to submit a FCC complaint also.

Userlevel 1

Bought a t-mobile branded Z-flip 3 from Samsung. Getting T-mobile updates and T-mobile crapware installed but the device is Network locked to T-mobile and showing as an unknown device on my dashboard. This is really bad customer service.

I’m about to submit a FCC complaint also.

What would be the grounds for the complaint?   Presumably not just that it shows as an unknown device on a web page?   If T-mobile can’t unlock it once you meet the conditions, then that would make sense.

Userlevel 7
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Bought a t-mobile branded Z-flip 3 from Samsung. Getting T-mobile updates and T-mobile crapware installed but the device is Network locked to T-mobile and showing as an unknown device on my dashboard. This is really bad customer service.

I’m about to submit a FCC complaint also.

T-Mobile branded devices, even ones sold by OEM's, are all sold network locked. 

Just know, My wife’s unlocked iPhone 12 Pro and my iPad both show up correctly. It’s definitely something between Samsung and T-mobile.

So why does customer support keep leading me to believe this is a “glitch” and a “fixable” thing. And that I should expect it to be remedied within 48 to 72 hours?

I wish I knew.  Support and Customer Care sometimes say things just to get people off of the phone without being more annoyed than when they called.  Your device showing as an unknown device does not restrict it in any way.  If the device is capable of using T-Mobile's implementation of it, it will work as long as the appropriate settings are correct. 

 

I have had multiple unlocked phones purchase elsewhere and used on T-Mobile where my account was able to identify the device and IMEI numbers. One device even got purchased internationally and had the details on my account. Yet some other devices, T-Mobile my account page recognized that it was a ‘Galaxy S10’ but nothing else about the phone or compatibility section. 

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