How to flash a AT&T Galaxy S9 SM-G960U with a T-Mobile Stock Rom?

[Youdoofus]

Hey guys I'm a newbie I got a s9 from Samsung as a replacement & its locked to tmobile. Becuz the 1 I sent in was a tmobile phone. T mobile will not give me the unlock code for this new device becuz I dont have an account and they have no record of this phone & I've even had Samsung call talk to them but I dont wanna switch to tmobile to make an account to unlock it.. Is there any way to unlock it to use on a different carrier?

yes, but you ll need to buy an unlock code if you cant get it from the carrier it came from. I used www dot androidsimunlock dot com. Its $29, but it worked for mine and my buddies S9. 3 business day wait too, but i got both codes, and they worked seamlessly

 

[leftylok83]

Samsung or a third party unlocking service are your only options. Even if you were a T-mobile customer, they would not be able to give you an unlock for a device they did not provide.

Ok thanks

 

[Youdoofus]

Ok thanks

no problem. it sucks, but it is what it is. i know there are cheaper places to get the code, but i cant speak from experience about how those other sites are.

 

[leftylok83]

Its all good I just want to use my phone again. Thank you for that its cheaper than the 1 I was looking at

 

[Youdoofus]

B"H

Ok, thank you.

1. So stock G960U (Original Carrier) -> Flash to U1 -
2. Then, Go from G960U1 -> Stock G960U (Any Carrier)

Few questions:
1. Which CSC file are you using to flash -- CSC_HOME?
2. In moving from U1 -> U, do you need the final carrier SIM inside the phone?

I've tried this with a Verizon phone I'd like to convert to XFinity (CCT). I flashed the G960U VZW to G960U1 XXA. That worked fine. Then I flashed the G960U CCT rom, and the phone just boots up Verizon. When I check the CSC, it says "VZW/VZW/VZW", even though I flashed the CCT rom.

I don't have an XFinity sim card, so perhap that is the problem.

Any help would be great.

so, what carrier are you trying to use this with?

also, the HOME_CSC wont factory reset your phone, the CSC will. Pretty much the only difference between those files

 

[dovid]

so, what carrier are you trying to use this with?

also, the HOME_CSC wont factory reset your phone, the CSC will. Pretty much the only difference between those files

At the time, I was trying to flash to TMobile. We figured out that we must have the sim card in for it to work.

Also, we are only able to get TMB/TMB/VZW to show up on the info screen. We cannot seem to convert that last VZW to the new flashed carrier TMB.

Any insight into that?

 

[Youdoofus]

At the time, I was trying to flash to TMobile. We figured out that we must have the sim card in for it to work.

Also, we are only able to get TMB/TMB/VZW to show up on the info screen. We cannot seem to convert that last VZW to the new flashed carrier TMB.

Any insight into that?

why is that important really? i have a Cricket S9 and flashed the U1 firmware and it works perfectly fine. Is there an issue youre trying to correct? Is something not working? Or is it just a thing where you want a specific firmware set to show up in the phone info screen?

 

[jcsww]

At the time, I was trying to flash to TMobile. We figured out that we must have the sim card in for it to work.

Also, we are only able to get TMB/TMB/VZW to show up on the info screen. We cannot seem to convert that last VZW to the new flashed carrier TMB.

Any insight into that?

The last tag of the 3 is the carrier or retailer that sold it. It has no impact on the firmware your device is running.

 

[supasieu]

Does anyone know if I can flash ROM on my Galaxy S9+ Dual Sim international to use with T-Mobile? The phone is working with call/text/data but data only give me 4G (speedtest around 5mbps), the LTE does not active. I've tried T-mobile and verizon sim card but same result. Thanks.

 

[jcsww]

Does anyone know if I can flash ROM on my Galaxy S9+ Dual Sim international to use with T-Mobile? The phone is working with call/text/data but data only give me 4G (speedtest around 5mbps), the LTE does not active. I've tried T-mobile and verizon sim card but same result. Thanks.

4G is LTE and 4G+ is LTE-A. It's just an icon. You might get better speeds with a hybrid ROM, but you can't flash a full image T-Mobile firmware to an Exynos version of the device.

 

[supasieu]

4G is LTE and 4G+ is LTE-A. It's just an icon. You might get better speeds with a hybrid ROM, but you can't flash a full image T-Mobile firmware to an Exynos version of the device.

Using the same SIM card on my Galaxy S8+ from T-Mobile I can get up to 100mbps speedtest, but on the Galaxy S9+ the max I can get is 5mbps. Do you know any hybrid ROM that I can try it out? Thanks.

 

[jcsww]

Using the same SIM card on my Galaxy S8+ from T-Mobile I can get up to 100mbps speedtest, but on the Galaxy S9+ the max I can get is 5mbps. Do you know any hybrid ROM that I can try it out? Thanks.

Carrier aggregation, radio tuning, and APN settings more than likely make the difference.

I don't personally use any hybrid ROM's but look for the T-Mobile Exonos based ROM's. They are essentially the Exynos base with the T-Mobile radio and CSC.

 

[supasieu]

Carrier aggregation, radio tuning, and APN settings more than likely make the difference.

I don't personally use any hybrid ROM's but look for the T-Mobile Exonos based ROM's. They are essentially the Exynos base with the T-Mobile radio and CSC.

Thanks.
just check imei on imei.info and it say the phone is
OS:Android 8.0 Oreo
Chipset:Qualcomm Snapdragon 845

 

[jcsww]

Thanks.
just check imei on imei.info and it say the phone is
OS:Android 8.0 Oreo
Chipset:Qualcomm Snapdragon 845

If you have a South American SnapDragon Dual-SIM device. That gets into a whole different mess. There should be threads on those too, just less common. Full firmware versions that have U1, U, or W in the model number, are all cross-flashable with the right steps.

 

[Youdoofus]

Using the same SIM card on my Galaxy S8+ from T-Mobile I can get up to 100mbps speedtest, but on the Galaxy S9+ the max I can get is 5mbps. Do you know any hybrid ROM that I can try it out? Thanks.

this problem is likely caused by the LTE bands enabled on the phone. One of the biggest obstacles to overcome when switching carrier IMO

 

[yan74s]

Does anyone know if I can flash ROM on my Galaxy S9+ Dual Sim international to use with T-Mobile? The phone is working with call/text/data but data only give me 4G (speedtest around 5mbps), the LTE does not active. I've tried T-mobile and verizon sim card but same result. Thanks.

Hello
It seems that is impossible, I have the same problem but inverted .... I have an US model and I need an international one... Because I have LTE instead of 4G

 

[jcsww]

Hello
It seems that is impossible, I have the same problem but inverted .... I have an US model and I need an international one... Because I have LTE instead of 4G

LTE and 4G are the same same thing! LTE-A and 4G+ are also the same. It's just an icon.

 

[Youdoofus]

Hello
It seems that is impossible, I have the same problem but inverted .... I have an US model and I need an international one... Because I have LTE instead of 4G

LTE and 4G are the same same thing! LTE-A and 4G+ are also the same. It's just an icon.

they kind of are just icons. 4G and LTE are both marketing terms used to put something easily remembered on a technology that is far more diverse than LTE or 4G can properly label. They only made those terms for end user ease of operation.

the biggest thing ive seen is that the LTE and 4G icons will show depending on which bands you have enabled on your device. I know this because ive had this exact issue and was able to enable some LTE bands in the service menu which changed the connection icon

 

[supasieu]

Update:
I get very slow data connection (0-2mbps) from T-Mobile in most of the locations (surrounding Seattle area within 75 miles radius). One time I was in a Verizon store and got a speedtest up to 33mbps. Another time I was in central of Seattle and got 25mbps, then drove 1/4 miles away and it dropped down to 0.1mbps.
I'm not sure if I flash ROM will it help or sell it.
Thanks.

 

[yan74s]

I know that 4G is a commercial name for LTE...
But it's also a question of frequencies that are used by operators oin different countries.
My issue is that my US phone tries to connect on frequencies that are not the officials in my country.
That's why the signal is very poor, and theG/LTE very slow ....

I found a solution with the app NetMonster (free app in the play store) : with It, we can change the prefered network type, It helps, but not enough to change the prefered frequencies of the networks ...