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

Search This thread

Youdoofus

Retired Forum Moderator
Feb 21, 2011
3,507
1,022
Sioux Falls, SD
Samsung Galaxy S9
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
 
  • Like
Reactions: leftylok83

leftylok83

Member
Jun 22, 2019
5
0
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

Retired Forum Moderator
Feb 21, 2011
3,507
1,022
Sioux Falls, SD
Samsung Galaxy S9
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
 
Last edited:

dovid

Senior Member
Apr 26, 2006
105
26
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

Retired Forum Moderator
Feb 21, 2011
3,507
1,022
Sioux Falls, SD
Samsung Galaxy S9
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

Senior Member
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

Member
Jul 16, 2013
16
2
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

Senior Member
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

Member
Jul 16, 2013
16
2
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

Senior Member
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

Member
Jul 16, 2013
16
2
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
 
Last edited:

jcsww

Senior Member
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. :p 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

Retired Forum Moderator
Feb 21, 2011
3,507
1,022
Sioux Falls, SD
Samsung Galaxy S9
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

Senior Member
Aug 6, 2008
192
16
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
 

Youdoofus

Retired Forum Moderator
Feb 21, 2011
3,507
1,022
Sioux Falls, SD
Samsung Galaxy S9
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

Member
Jul 16, 2013
16
2
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

Senior Member
Aug 6, 2008
192
16
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 ...
 

Top Liked Posts

  • There are no posts matching your filters.
  • 7
    I've done it!

    Any chance anybody has success doing this? It seems like a "Must Have" feature to switch carrier roms on the G960U between carriers, including Boot Screen/Logo, Firmware, Bloatware, etc.

    All the goodies.

    Any help?

    Thank you,

    I've completed this task tonight thanks to some great help from a user that stepped me through it on a TMO Forum.

    First an FYI, I first was able to flash my AT&T S9 version from SM-960U to a Stock SM-960U1. It worked great. After that, I was able to flash the TMO Rom and it's also working perfect. I'm not sure if it's required or not to flash the phone to a U1 first or if the TMO Rom can just be flashed. After I flashed the TMO firmware, I had no issues downloading and installing the latest TMO update. (My device is unlocked as well)

    It's best to use Samsung switch first to backup your texts, pics, etc. first if you want to restore them to the device after completing the flash. The below instructions will start the phone up as if it was new out if the box.

    Here is what I was provided with and the steps I followed.

    To Flash the SM-G960U to a SM-G960U1

    1. Allow\Enable USB Debugging in Developers settings.

    2. Download the U1 Firmware here: https://androidfilehost.com/?w=files&flid=257063
    (this is the U1 from Samsung, it's compressed but once extracted it will be around 4GB's of data.)

    3. Download the ADB tools: https://devfiles.co/download/PDYvOWBg/platform-tools-latest-windows.zip. Create a folder on your desktop and name it ADB (for easy reference)

    4. Download Odin: https://drive.google.com/file/d/10dSyPTuccP8Km9MnDrvbRdS-CAcgFZB3/view

    5. From windows, run command prompt, in the command prompt type the following: cd C:\Users\XXX\Desktop\ADB
    (XXX is your username)

    6. Connect your phone to a USB port on your computer, your phone should prompt you to allow the connection to\from your computer. Allow the connection. Might be best to choose to "Always Allow"

    7. Return to the command prompt and type in: adb devices You should see your device listed.

    8. In the same command window, type in: adb reboot bootloader This will auto reboot your device into the "Download" mode.

    9. Open and run Odin, add the corresponding tar files to the respective area's, in the "options tab" in Odin, make sure that only "Auto Reboot" and "F. Reset Time" is checked.

    Click "Start" and the process will take a few minutes to complete.

    Allow the device a few minutes to auto reboot and start up.

    After you get through all the post boot setup screens, open a phone dial pad and type in, *#2263#. then make sure that all LTE bands are enabled.

    Here you can find the SM-G960U T-Mobile Files: https://www.droiddosh.com/2018/04/samsung-galaxy-s9-sm-g960u-firmware-tmobile-usa-G960USQU1ARBG.html
    1
    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.

    You most likely will need a Xfinity Sim Card. I was able to convert my Xfinity Mobile S9 to AT&T by going to U1 firmware then inserting my AT&T sim card then flashing the AT&T U firmware.
    1
    Question

    Does anyone know if you have to have the phone unlocked before changing over carriers? for example if i had a Galaxy S9 from Sprint and wanted to change the firmware to T-Mobile would it work or would it still be locked to Sprint? Thanks for your Help!
    1
    Can anyone help please ODIN file is not available.

    You can find it here.
    1
    Thanks, I have a question, I am try to flash T-Mobile ROM on xifinity S9 that has android 8 on it. should I proceed with the same process. or get the latest T-Mobile ROM. Please help

    You need to factory wipe and flash to the U1 non-carrier specific firmware first after enabling USB Debugging in the Developer Options once you factory reset. Pop your T-Mobile SIM in and put the device into download mode. Make sure you find the U1 version that has the same or a newer bootloader than your device currently has. You can not flash a previous version of the bootloader. Do not use the file called, HOME_CSC when flashing any of the firmware unless you want the potential for issues. Once you flash the U1, skip through the setup, don't activate WiFi or sign in with your Google account and head straight to enable USB Debugging once again in Developer Options. Back into download mode and flash the TMB firmware, again making sure you don't flash the HOME_CSC (there is another CSC that does need to be flashed) and everything should be good.