Previously on the S4 I came to the conclusion I could use the international variant of it on Verizon as it had the proper CDMA bands for the job, is this the same case with the S6? Could I buy the international one that is unlocked and use it on VZW network without problems and if I have them what would they be? Going to do my own homework of course but I always want XDA's opinion on things like this.
S1L3nTShaDoWz said:
Previously on the S4 I came to the conclusion I could use the international variant of it on Verizon as it had the proper CDMA bands for the job, is this the same case with the S6? Could I buy the international one that is unlocked and use it on VZW network without problems and if I have them what would they be? Going to do my own homework of course but I always want XDA's opinion on things like this.
Click to expand...
Click to collapse
I was actually in the process of typing up this thread myself! I am also interested in the answer to this one. And can the international version be rooted? I need me some Greenify!
Edit: After speaking to a Verizon rep online, I was told "In theory, it should work; but we cannot guarantee device usability and stability from non-verizon devices".
Any other XDA thoughts?
Basketballhero75 said:
I was actually in the process of typing up this thread myself! I am also interested in the answer to this one. And can the international version be rooted? I need me some Greenify!
Edit: After speaking to a Verizon rep online, I was told "In theory, it should work; but we cannot guarantee device usability and stability from non-verizon devices".
Any other XDA thoughts?
Click to expand...
Click to collapse
The International one is fully bootloader unlockable and rootable from the start, hence why I want it over this locked down one. Though someone suggested to me in a PM to post this in the international forum so I will try that and update here with whatever results I get.
S1L3nTShaDoWz said:
The International one is fully bootloader unlockable and rootable from the start, hence why I want it over this locked down one. Though someone suggested to me in a PM to post this in the international forum so I will try that and update here with whatever results I get.
Click to expand...
Click to collapse
From what I could find it won't work because it's GSM and won't work with CDMA carriers. Here is a link to the info I found.
I remember reading that the Verizon and Sprint variants have a separate Qualcom modem in them to connect to their CDMA and LTE bands.
I have the US Verizon Galaxy S6 as well as my wife now. Currently in Cancun using a popped in TelCel SIM card seeing crazy 4G speeds on the hotel strip area.
So yea. The S6 from Verizon is killer with foreign SIMs.
Lil
lilsalmon said:
I have the US Verizon Galaxy S6 as well as my wife now. Currently in Cancun using a popped in TelCel SIM card seeing crazy 4G speeds on the hotel strip area.
So yea. The S6 from Verizon is killer with foreign SIMs.
Lil
Click to expand...
Click to collapse
Can i ask what this has to do with OPs question?
Sorry I just reread the post and thought it was referencing using the vzw version abroad.
You can delete my post if it offends you that much. Was just trying to help because I just went through the process of using it in Mexico for the first time.
It's not that big of a deal, I just thought I was missing something
No worries here ...
Any answers yet? Thanks.
Just want to let you all know the international version will not work on Verizon.
I have one was going to sell on craigslist and we met at verizon and it will not recognize the mobile network.
Im still trying to sale this thing lol
Related
I am buying a verizon galaxy S3 off craigs list and the model number is SCH-I535V , is it the same as SCH-I535 ?
Also what is the best way to unlock it to use with AT&T with most functionality. Please point me to the appropriate "how to"s if possible.
Thanks in advance.
bothambhai said:
I am buying a verizon galaxy S3 off craigs list and the model number is SCH-I535V , is it the same as SCH-I535 ?
Also what is the best way to unlock it to use with AT&T with most functionality. Please point me to the appropriate "how to"s if possible.
Thanks in advance.
Click to expand...
Click to collapse
My brother in law received a Verizon replacement and it's SCH-I535v, I guess the V is to identify Verizon model vs others?
buhohitr said:
My brother in law received a Verizon replacement and it's SCH-I535v, I guess the V is to identify Verizon model vs others?
Click to expand...
Click to collapse
All US versions of the S3 already have completely different model numbers.
I've never heard of that maybe it means verizon refurbished? and as far as i know you can't unlock it to work with att. You could before but from what i saw he pulled it as it wasnt working well.
fr8cture said:
I've never heard of that maybe it means verizon refurbished? and as far as i know you can't unlock it to work with att. You could before but from what i saw he pulled it as it wasnt working well.
Click to expand...
Click to collapse
Wow, I had read sometime back there was some work going on regarding this....so no headway yet huh, must be some lock these guys put up.
I am going to take your advice and stay away from this phone then as I need it to work with ATT here and other gsm networks abroad.
bothambhai said:
Wow, I had read sometime back there was some work going on regarding this....so no headway yet huh, must be some lock these guys put up.
I am going to take your advice and stay away from this phone then as I need it to work with ATT here and other gsm networks abroad.
Click to expand...
Click to collapse
Dont quote me on that but even if so it wont work as well as just getting a gsm model.
Which roms or leaks have a carrier unlock ..
I been looking around cant seem to find a definite answer ... so does cleanrom give your phone capability in using any carrier .. I just need to be be sure I have to cut my chip into a microchip in order to use the phone .. Before I do this i need to be sure it would work ..
I have version 4.1.1
No ROM has that it is an entirely different procedure involving unlocked sim cards.
Please read forum rules before posting
Questions and help issues go in Q&A
Thread moved
Thank you for your cooperation
Friendly Neighborhood Moderator
Kenof said:
Which roms or leaks have a carrier unlock ..
I been looking around cant seem to find a definite answer ... so does cleanrom give your phone capability in using any carrier .. I just need to be be sure I have to cut my chip into a microchip in order to use the phone .. Before I do this i need to be sure it would work ..
I have version 4.1.1
Click to expand...
Click to collapse
There is a thread for getting the VZW S3 to work on T-Mobile, but it takes some work:
http://forum.xda-developers.com/showthread.php?t=2013647
A few ROMs (as you indicated with CleanRom) have universal installers for different Carriers, but in no way does this mean that it will allow you to switch your phone to AT&T, Sprint, or any other carrier.
mapatton82 said:
There is a thread for getting the VZW S3 to work on T-Mobile, but it takes some work:
http://forum.xda-developers.com/showthread.php?t=2013647
A few ROMs (as you indicated with CleanRom) have universal installers for different Carriers, but in no way does this mean that it will allow you to switch your phone to AT&T, Sprint, or any other carrier.
Click to expand...
Click to collapse
So cleanrom has a universal installer for At&T/H20 ? Is there a way to completely use on all carriers like a unlocked iphone ?
Kenof said:
So cleanrom has a universal installer for At&T/H20 ? Is there a way to completely use on all carriers like a unlocked iphone ?
Click to expand...
Click to collapse
Reread the last sentence of his reply, especially the part after the comma.
landshark68 said:
Reread the last sentence of his reply, especially the part after the comma.
Click to expand...
Click to collapse
eh theres always a way ..
Correct me if I'm wrong.
But.
The Verizon galaxy s3 uses a CDMA antenna.
So if you were to unlock it. You could use on CDMA carries.( Verizon Wireless, Sprint, MetroPCS, Cricket, and U.S. Cellular)
However. If you can get your phone to FULLY work on GSM (T-MOBILE or at&t)
You should make a thread about it and I'm sure you will get tons of donations.
There is already something for T-Mobile. But I heard it has limited success.
Sent from team liquid smooth.
Vice Versa
Still a noob to the development scene, but long time surface runner in rooting/etc.
That being said, if this can be done (I took a look at the thread linked above), couldn't it technically work the other way around?
My fiancee has a Galaxy on T-Mobile, but wants the GS3. Her contract runs out about the same time as mine so I thought, I'll give you my S3 and buy the S4 for myself (she doesn't always need the latest and greatest like I do what can I say I'm a technophile). I quickly learned about locked phones, different network types, etc. In this case, since there's a 4GLTE SIM card in my S3, is it possible to give it to her to use on T-Mobile? In that case I may just migrate over to T-Mobile myself, since it's significantly cheaper for what I need in a cell phone plan. Otherwise, we're currently looking at adding a line to my Verizon plan so she can leave T-Mobile. Honestly, I'm OK with either idea, since I'm either saving money by going to T-Mobile, or sticking with great network coverage and speed on Verizon.
Psychotacon said:
Still a noob to the development scene, but long time surface runner in rooting/etc.
That being said, if this can be done (I took a look at the thread linked above), couldn't it technically work the other way around?
My fiancee has a Galaxy on T-Mobile, but wants the GS3. Her contract runs out about the same time as mine so I thought, I'll give you my S3 and buy the S4 for myself (she doesn't always need the latest and greatest like I do what can I say I'm a technophile). I quickly learned about locked phones, different network types, etc. In this case, since there's a 4GLTE SIM card in my S3, is it possible to give it to her to use on T-Mobile? In that case I may just migrate over to T-Mobile myself, since it's significantly cheaper for what I need in a cell phone plan. Otherwise, we're currently looking at adding a line to my Verizon plan so she can leave T-Mobile. Honestly, I'm OK with either idea, since I'm either saving money by going to T-Mobile, or sticking with great network coverage and speed on Verizon.
Click to expand...
Click to collapse
If you look up, you'll see how you can use the VZW GSIII on TMO. I think the primary issue would be that you only get Edge data when using the VZW GSIII on TMO.
For pricing, TMO is better plus you can stop worrying about third party hacks to use a phone on another carrier since top unlocked GSM phones can be imported.
So I went to a Tmobile store and looked at the Galaxy s8+ and noticed the model was 955U not 955T
It was of course their demo unit which was strapped (tethered) to the desk which makes it impossible to feel properly in the hand... But whatever.
Curious if only the demo model was a U variant or what? I never payed attention to other models before now?
The U variant of other Samsung models, do they have Locked bootloaders? Is it only the F variant that is unlocked (bootloader)
Sent from my Rooted Galaxy S7 EDGE on Android 7.0 Nougat, here's the instructions how to do it!
The SM-G955U is suppose to be the Unlock variant of the S8+, which make it super interesting, Hope this comes with unlock bootloader
Araltd said:
So I went to a Tmobile store and looked at the Galaxy s8+ and noticed the model was 955U not 955T
It was of course their demo unit which was strapped (tethered) to the desk which makes it impossible to feel properly in the hand... But whatever.
Curious if only the demo model was a U variant or what? I never payed attention to other models before now?
The U variant of other Samsung models, do they have Locked bootloaders? Is it only the F variant that is unlocked (bootloader)
Sent from my Rooted Galaxy S7 EDGE on Android 7.0 Nougat, here's the instructions how to do it!
Click to expand...
Click to collapse
All snapdragon s7 edge have locked bootloader including the g935u so I'm assuming the same thing with the s8 hope this helps (unless someone finds a way to root s8)
[email protected] said:
All snapdragon s7 edge have locked bootloader including the g935u so I'm assuming the same thing with the s8 hope this helps (unless someone finds a way to root s8)
Click to expand...
Click to collapse
With the S8 and S8+ they are using single SKU..Verizon, At&t and T-Mobile will be the same model number. Screenshot of my S8 recovery screen.
According to Samsung.com and the phones full specs they are each different
https://forum.xda-developers.com/showthread.php?p=71771523
You guys think flashing another carriers firmware unlocks the missing bands?
None of the U's are bootloader unlocked. They are just network unlocked. At least starting with the S7 in my experience. Its a hopeful thought though. I hope I am wrong
johnwayne27 said:
None of the U's are bootloader unlocked. They are just network unlocked. At least starting with the S7 in my experience. Its a hopeful thought though. I hope I am wrong
Click to expand...
Click to collapse
Sadly, if purchased through the carrier, they will be sim locked
bossg4 said:
Sadly, if purchased through the carrier, they will be sim locked
Click to expand...
Click to collapse
That is absolutely right. Only exception being TMO will work with a prepaid MetroPCS sim and ATT with work with a Cricket sim.
That's really interesting. So I purchased a T-mobile model directly from Samsung.com (paid in full), will I possibly be able to use it on At&t?
J4B3 said:
That's really interesting. So I purchased a T-mobile model directly from Samsung.com (paid in full), will I possibly be able to use it on At&t?
Click to expand...
Click to collapse
From what I read I'm not sure how long it will take to have T-Mobile officially unlock it. They have an app for that but they have several different criteria as far as being a current customer or a prepaid versus postpaid customer. Ive never unlocked a T-mobile phone with the app or a third party unlocking service so maybe someone with examples could chime in. It does seem AT&T has an easier online unlocking method for current and non customers to simply fill out a form.
And the U models are slow with updates
Sent from my SM-G935T using XDA-Developers Legacy app
954wrecker said:
According to Samsung.com and the phones full specs they are each different
https://forum.xda-developers.com/showthread.php?p=71771523
You guys think flashing another carriers firmware unlocks the missing bands?
Click to expand...
Click to collapse
bossg4 said:
Sadly, if purchased through the carrier, they will be sim locked
Click to expand...
Click to collapse
Vz is unlocked. All Vz phones are.
suzook said:
Vz is unlocked. All Vz phones are.
Click to expand...
Click to collapse
Doh! That is true. May be best to buy verizon if you want it unlocked from day one
bossg4 said:
Doh! That is true. May be best to buy verizon if you want it unlocked from day one
Click to expand...
Click to collapse
But it's missing a few T-Mobile and AT&T bands
954wrecker said:
But it's missing a few T-Mobile and AT&T bands
Click to expand...
Click to collapse
Oh God! Would you stop with this nonsense? It has all bands.
suzook said:
Oh God! Would you stop with this nonsense? It has all bands.
Click to expand...
Click to collapse
Don't be mad at me that both Verizon and Samsung and each carrier list different bands. I hate them all F these companies trying to screw us all with misinformation.
954wrecker said:
Don't be mad at me that both Verizon and Samsung and each carrier list different bands. I hate them all F these companies trying to screw us all with misinformation.
Click to expand...
Click to collapse
It's SW related, I keep telling you this.
suzook said:
It's SW related, I keep telling you this.
Click to expand...
Click to collapse
I asked for some proof and you provided zero. I have to trust the carriers and the company that makes the phones. I didn't make the carriers all list a ton of random bands nobody needs and leave off the few we need in this country. I hate the carriers amd samsung trust me I want you to be right.
954wrecker said:
I asked for some proof and you provided zero. I have to trust the carriers and the company that makes the phones. I didn't make the carriers all list a ton of random bands nobody needs and leave off the few we need in this country. I hate the carriers amd samsung trust me I want you to be right.
Click to expand...
Click to collapse
Stop with the drama. Note 7, and galaxy S7 are the same.
suzook said:
Stop with the drama. Note 7, and galaxy S7 are the same.
Click to expand...
Click to collapse
I like how the facts I researched are drama and the speculation you spread are facts? Yet still not one link for proof of anything you keep claiming?
On most carriers my phone is not compatiable what do I need to do to get this phone onto any network? I had it unlocked by a very well respected website plz help o and the model isSM-G 955U I JUST bought the straight talk BYOB can anybody help greatly appreciated
Go back to that respectable company that gave you the unlock code and asked them why.You paid for a service and you didn't get what you expected.That should have been your first step. They will check with you 1st if the phone is really unlocked or not.Good luck.
Your device might be a CDMA one. Thus, you will not be able to use it on all networks.
What is the network of the SIM card you are trying to use?
RossTeagan said:
Your device might be a CDMA one. Thus, you will not be able to use it on all networks.
What is the network of the SIM card you are trying to use?
Click to expand...
Click to collapse
All of the North America (Snapdragon) S8 (and plus) have all NA bands, including CDMA. It's the Exynos (European and Asian) variants that do not support CDMA.
RossTeagan said:
Your device might be a CDMA one. Thus, you will not be able to use it on all networks.
What is the network of the SIM card you are trying to use?
Click to expand...
Click to collapse
I have ATnT t mobile sprint and Verizon from straight talk came in a their byob but I thought the s8 is cdma gan and lte
Pr3vo5t said:
I have ATnT t mobile sprint and Verizon from straight talk came in a their byob but I thought the s8 is cdma gan and lte
Click to expand...
Click to collapse
You are correct. The S8 is CDMA capable.
USCC S8 is unlocked out the box, I had s6 that work on ATT and Tmobile by go into setting -> connect -> force it switch to Global/GSM. The problem I have with all these CDMA phone unlock for GSM is can't get MMS and the most annoying thing is someone in the state call it kept thinking as internaltional call. Example like 201xxxxxxxxx, the phone think 20 is from Egypt.
Hopefully, S8 is will do what iPhone can..... fix the area code issue.
cam30era said:
All of the North America (Snapdragon) S8 (and plus) have all NA bands, including CDMA. It's the Exynos (European and Asian) variants that do not support CDMA.
Click to expand...
Click to collapse
So basically the new S8 should support both CDMA and GSM right?
---------- Post added at 02:02 PM ---------- Previous post was at 02:00 PM ----------
Pr3vo5t said:
I have ATnT t mobile sprint and Verizon from straight talk came in a their byob but I thought the s8 is cdma gan and lte
Click to expand...
Click to collapse
What is the exact message your device displays when inserting an att card?
RossTeagan said:
So basically the new S8 should support both CDMA and GSM right?
Click to expand...
Click to collapse
Correct for the US (snapdragon) version. The Exynos version does not support CDMA.
Edit: See posts #10 and #12 below for clarification from @zelendel.
cam30era said:
Correct for the US (snapdragon) version. The Exynos version does not support CDMA.
Click to expand...
Click to collapse
That depends on where in the US you are. All devices in my state are Euro devices and none are the US model. Even the Straight talk devices are Euro models.
zelendel said:
That depends on where in the US you are. All devices in my state are Euro devices and none are the US model. Even the Straight talk devices are Euro models.
Click to expand...
Click to collapse
Really? I didn't know that. My understanding was that all major US carriers were only selling snapdragon variants. And the big box stores, as well.
Would you mind sharing what state you are in, and who sells the Exynos version in the US?
Thanks....
cam30era said:
Really? I didn't know that. My understanding was that all major US carriers were only selling snapdragon variants. And the big box stores, as well.
Would you mind sharing what state you are in, and who sells the Exynos version in the US?
Thanks....
Click to expand...
Click to collapse
I live in Alaska. As for the major US carriers. Yeah well we have ATT and verizon just got here but they are both thinking about leaving (not the first time) People in this state prefer Companies founded in the state so our biggest carrier is GCI. I am used by alot of devs to get the "good" devices without them having to pay stupid shipping. But you can walk into any store here and buy the euro device. Even walmart.
zelendel said:
I live in Alaska. As for the major US carriers. Yeah well we have ATT and verizon just got here but they are both thinking about leaving (not the first time) People in this state prefer Companies founded in the state so our biggest carrier is GCI. I am used by alot of devs to get the "good" devices without them having to pay stupid shipping. But you can walk into any store here and buy the euro device. Even walmart.
Click to expand...
Click to collapse
Amazing (as in good). Thanks for setting the record straight.
cam30era said:
Amazing (as in good). Thanks for setting the record straight.
Click to expand...
Click to collapse
Glad I could help. It freaked me out as well the first time I found this out. Being here gave me the ability to get a Samsung devicewith a snapdragon chip and an unlockable bootloader. Mid you that was a few generations ago but I keep tabs on what they are offering in case someone hits me up to get them one.
Also helps that there is no sales tax here.
RossTeagan said:
So basically the new S8 should support both CDMA and GSM right?
---------- Post added at 02:02 PM ---------- Previous post was at 02:00 PM ----------
What is the exact message your device displays when inserting an att card?
Click to expand...
Click to collapse
It just says mobile network not available and the network is a circle with a / through it. It reads the sim cards just for some odd reason its not doing what it should do
Pr3vo5t said:
It just says mobile network not available and the network is a circle with a / through it. It reads the sim cards just for some odd reason its not doing what it should do
Click to expand...
Click to collapse
Try to use another SIM card from a GSM provider (att or tmob) and at the same time, insert your present SIM card in another device to see if it works.
or if you fix the issue already, let me know
Pr3vo5t said:
It just says mobile network not available and the network is a circle with a / through it. It reads the sim cards just for some odd reason its not doing what it should do
Click to expand...
Click to collapse
Check your imei. If it is wiped you won't be able to connect
Uhuuu. That would be bad. IMEI can be wiped only by a custom rom correct? Bad or wrong recovery etc.
zelendel said:
Check your imei. If it is wiped you won't be able to connect
Click to expand...
Click to collapse
jb_alphamale said:
Uhuuu. That would be bad. IMEI can be wiped only by a custom rom correct? Bad or wrong recovery etc.
Click to expand...
Click to collapse
Depending on the device. Samsung devices are known for self corruption. That has been their MO since windows mobile.
It shows what my imei is and it says my phone number and everything just not be no service circle
Hey all,
I'm looking at getting an Exynos or an HK version of the S22 series. I saw none of the other versions besides the U supports bands 29 and 30 that AT&T uses. Since they seem to be the more minor bands, how much does it matter and how much does the lack of those bands impact service? And does AT&T ban those S22 versions from their 5G networks?
I'm starting to get tired of OP, but I want something I can tinker without having to deal with AT&T's Sammy versions.
Thanks!
AT&T won't support the international models on their network or so various users have said in other posts. You end up locked out. T-Mobile doesn't do this but the long range 5G and LTE band 71 is missing from the international versions which would mean no coverage in any areas using band 71. Either way you are screwed on AT&T and T-Mobile. Don't have any info on Verizon. Best suggestion is. (Don't Do It)
Paul_Deemer said:
AT&T won't support the international models on their network or so various users have said in other posts. You end up locked out. T-Mobile doesn't do this but the long range 5G and LTE band 71 is missing from the international versions which would mean no coverage in any areas using band 71. Either way you are screwed on AT&T and T-Mobile. Don't have any info on Verizon. Best suggestion is. (Don't Do It)
Click to expand...
Click to collapse
Crap. Guess my only option would be getting an AT&T version and using a paid service to unlock the BL and SIM.
We already tried T-Mobile last year and had a really bad experience with service and network quality, so they're out.
Thanks for the info!
You might want to rethink the Exynos version and look at one of the SD versions that can be rooted.
I am afraid you will not be able to get the bootloader unlocked (I may be wrong there). Rooting is not possible on the US or Canadian S22. I just switched to TMO this year and so far have had no issues. I use their 5G home internet too.
dalepl said:
You might want to rethink the Exynos version and look at one of the SD versions that can be rooted.
Click to expand...
Click to collapse
So is that the Hong Kong and Korea versions? Again brings up the question of if bands 29 and 30 missing impacts service and if so, how much.
If I get an AT&T BL unlocked with a paid service, can I root using the method listed in another thread?
Superguy said:
Crap. Guess my only option would be getting an AT&T version and using a paid service to unlock the BL and SIM.
We already tried T-Mobile last year and had a really bad experience with service and network quality, so they're out.
Thanks for the info!
Click to expand...
Click to collapse
I don't see the S22 series in the list yet. So might wanna further research that.
PSA: Unlock Bootloader on Snapdragon Galaxy Devices with SamPWND (Paid Service)
SamPWND is a paid remote service that allows you to unlock the bootloader on Snapdragon Samsung Galaxy devices sold in the USA and Canada.
www.thecustomdroid.com
There are many posts on here attesting to the fact that the US models of the S22 cannot be rooted. The BL cannot be unlocked, so no root.
May I ask what you are trying to achieve with root? Do you have something in mind or do you just want a custom ROM. There are other issues with rooting the phone. Main one is loss of Knox. This will stop the Samsung apps from working. So there is a trade-off no matter what.
dalepl said:
May I ask what you are trying to achieve with root? Do you have something in mind or do you just want a custom ROM. There are other issues with rooting the phone. Main one is loss of Knox. This will stop the Samsung apps from working. So there is a trade-off no matter what.
Click to expand...
Click to collapse
There are magisk mods I run on my phone as well as some Xposed mods.
Not terribly concerned about Samsung apps. I haven't had a Samsung phone in years. Last one I had was an S8 and I only got that thru insurance when I lost my OP6.
Understand. Just wanted to let you know that things like Samsung Pay and Health Monitoring will no longer work and this can not be fixed if you change your mind. I did read that AT&T will ban any international phone from their network, so you do not want to go that way if you intend on staying with them. I think there was talk about the Korean model being SD and was missing band 71 (I think). There is no full solution out there unless a way comes along to unlock the BL.
dalepl said:
Understand. Just wanted to let you know that things like Samsung Pay and Health Monitoring will no longer work and this can not be fixed if you change your mind. I did read that AT&T will ban any international phone from their network, so you do not want to go that way if you intend on staying with them. I think there was talk about the Korean model being SD and was missing band 71 (I think). There is no full solution out there unless a way comes along to unlock the BL.
Click to expand...
Click to collapse
AT&T doesn't use 71, so not a big deal. T-Mo did.
We tried T-Mo in the summer and had a horrible experience. We went running back to AT&T after 3 months.
When you say banned, are you talking about just the 5G or the entire network? I'm already blocked from 5G with my OP phones. I can't say I miss it as I wasn't impressed with it on T-Mo, and LTE does what I need it to do. Outright banning seems like a stupid thing to do, especially as a lot of foreign travelers could very well end up using AT&T while they're here. But then again, it IS AT&T ...
From what I read, AT&T will ban your IEMI if it is an international phone so it will not work on their network. They are the only ones that do this as far as I know.
https://forum.xda-developers.com/t/...lash-official-firmware-noob-friendly.4404283/
Check this out. Long read through all the posts, but may be able to answer your questions. There are other discussions on the US models and international models, so just look around.
You ain't gonna win with the U.S. Carriers. They absolutely don't want you rooting your phone on their networks. Why do you think all U.S. models have unlockable bootloader's when shipped from Samsung? Because they demand it. They also know you will try to get around it and when you do they will screw you by banning your device. If you gotta have a rooted phone move to another country lol.