[Q] At&t to T-Mobile

bradhoschar · Apr 22, 2013

Here's the issue. I purchased the At&t s3 (SGH-I747) last year. Long story short, I wanted to go to T-Mobile prepaid with the same phone.
I purchased the SIM activation kit for $10, popped my SIM in and it worked!
Before I put the SIM in it though, I paid for an unlock code. I still have the code.
No 'Network Unlock' screen.
No prompt for my unlock code.
I am getting H+ speeds with the at&t s3 on T-Mobile prepaid without doing ANYTHING.

My question is:

Why cant I get to the unlock screen? I have tried to dial "#7465625*638*# for the prompt to popup and NOTHING.

Can someone tell me...
1. Can I flash a T-mobile rom to this phone? (every time i try I get a build.prop error, even after changing the model to the T999 and all that jazz),
so I can't install a T-Mo rom?

2. Do I have to flash a modem/radio or anything else like that?

3. Or, should I just continue to flash At&t Roms with the t-mo prepaid sim?

I have searched for a while now, and noone has my problem. I never expected to just switch sim's and it would work, so ANY help would be appreciated.
Thanks!

Okaham · Apr 22, 2013

bradhoschar said:
Here's the issue. I purchased the At&t s3 (SGH-I747) last year. Long story short, I wanted to go to T-Mobile prepaid with the same phone.
I purchased the SIM activation kit for $10, popped my SIM in and it worked!
Before I put the SIM in it though, I paid for an unlock code. I still have the code.
No 'Network Unlock' screen.
No prompt for my unlock code.
I am getting H+ speeds with the at&t s3 on T-Mobile prepaid without doing ANYTHING.

My question is:

Why cant I get to the unlock screen? I have tried to dial "#7465625*638*# for the prompt to popup and NOTHING.

Can someone tell me...
1. Can I flash a T-mobile rom to this phone? (every time i try I get a build.prop error, even after changing the model to the T999 and all that jazz),
so I can't install a T-Mo rom?

2. Do I have to flash a modem/radio or anything else like that?

3. Or, should I just continue to flash At&t Roms with the t-mo prepaid sim?

I have searched for a while now, and noone has my problem. I never expected to just switch sim's and it would work, so ANY help would be appreciated.
Thanks!

since your device is still an AT&T branded Galaxy S III (SGH-i747), you must keep with ROMs designed for that phone. flashing T-Mobile branded Galaxy S III (SGH-T999) ROMs will brick your device, same thing goes for flashing modems.

just because your SIM and Carrier is now T-Mobile, doesn't mean your phone is.

tower_gilead · Apr 22, 2013

Okaham said:
since your device is still an AT&T branded Galaxy S III (SGH-i747), you must keep with ROMs designed for that phone. flashing T-Mobile branded Galaxy S III (SGH-T999) ROMs will brick your device, same thing goes for flashing modems.

just because your SIM and Carrier is now T-Mobile, doesn't mean your phone is.

You got that right.

:thumbup:

Sent while sleeping in chair.

Da Kine · Apr 22, 2013

Okaham said:
since your device is still an AT&T branded Galaxy S III (SGH-i747), you must keep with ROMs designed for that phone. flashing T-Mobile branded Galaxy S III (SGH-T999) ROMs will brick your device, same thing goes for flashing modems.

just because your SIM and Carrier is now T-Mobile, doesn't mean your phone is.

Wrong. Flashing an rom meant for the AT&T variant of the S3 on a T-Mobile variant S3 and vice versa will not brick the device. APN setting may get messed up and you have to enter them manually but it will not brick the device. Flashing a ROM for the international S3 on a U.S. variant of the S3 and vice versa will brick the device.

I wouldn't recommend flashing modems between the variants of S3s, that may or may not brick the device but wouldn't try it.

|When Emotion Goes up, Logic Goes Down|

---------- Post added at 03:40 PM ---------- Previous post was at 03:36 PM ----------

bradhoschar said:
Here's the issue. I purchased the At&t s3 (SGH-I747) last year. Long story short, I wanted to go to T-Mobile prepaid with the same phone.
I purchased the SIM activation kit for $10, popped my SIM in and it worked!
Before I put the SIM in it though, I paid for an unlock code. I still have the code.
No 'Network Unlock' screen.
No prompt for my unlock code.
I am getting H+ speeds with the at&t s3 on T-Mobile prepaid without doing ANYTHING.

My question is:

Why cant I get to the unlock screen? I have tried to dial "#7465625*638*# for the prompt to popup and NOTHING.

Can someone tell me...
1. Can I flash a T-mobile rom to this phone? (every time i try I get a build.prop error, even after changing the model to the T999 and all that jazz),
so I can't install a T-Mo rom?

2. Do I have to flash a modem/radio or anything else like that?

3. Or, should I just continue to flash At&t Roms with the t-mo prepaid sim?

I have searched for a while now, and noone has my problem. I never expected to just switch sim's and it would work, so ANY help would be appreciated.
Thanks!

If you want to unlock the S3 (you must be stock to do this, stocked rooted may work, but I'm not sure):

Just dial the following keys *#197328640#

Main Menu
[1] UMTS
[1] Debug Screen
[8] Phone Control
[6] Network Lock
Options [3]Perso SHA256 OFF
(after choosing this option, wait about 30 seconds, then go back one step by pressing the Menu button then select Back, now you are in
[6] Network Lock then choose
[4] NW Lock NV Data INITIALLIZ ..... wait for a minute then reboot your phone

|When Emotion Goes up, Logic Goes Down|

xmanberserker · Apr 23, 2013

Hello.

If you have signal then why are you trying to use the code? It is unlocked already!

im not an expert but this is what i know from reading a lot:

1.- I installed a t-mobile (t999) rom modified to work in a att s3 (i747), i think you can flash a any rom from the t999 section (i am not sure about this)

2.- Do NOT try to install a modem from t-mobile or you will hard brick your phone.

3.- Thats a good idea, do it and let me know if it works.

I used this files to convert an i747 to a t999 http://xdaforums.com/showthread.php?t=1771021&page=25 (read from post #246) so now i use customs roms for the t999 i did it because where i live do not have good signal, was stuck at edge and with those files now i have 3g signal.

Btw, i am in the $30 prepaid t mo plan.

KennyG123 · Apr 23, 2013

Please read forum rules before posting
Questions and help issues go in Q&A
Thread moved
Thank you for your cooperation
Friendly Neighborhood Moderator

Misterjunky · Apr 23, 2013

re: Hmm

xmanberserker said:
Hello.

If you have signal then why are you trying to use the code? It is unlocked already!

im not an expert but this is what i know from reading a lot:

1.- I installed a t-mobile (t999) rom modified to work in a att s3 (i747), i think you can flash a any rom from the t999 section (i am not sure about this)

2.- Do NOT try to install a modem from t-mobile or you will hard brick your phone.

3.- Thats a good idea, do it and let me know if it works.

I used this files to convert an i747 to a t999 http://xdaforums.com/show...771021&page=25 (read from post #246) so now i use customs roms for the t999 i did it because where i live do not have good signal, was stuck at edge and with those files now i have 3g signal.

Btw, i am in the $30 prepaid t mo plan.

#1: If you have a Unlocked AT&T I747 Galaxy S3 you don't need any files to convert it to work on any T999 Tmobile roms.
#2: You can use any T999 Tmobile custom roms as long as you have an Unlocked & Rooted AT&T Galaxy S3 I747 Phone.
#3: There is no such thing as installing or flashing any files which would would change the frequency for 3G on a I747 phone.

#4: Your link is dead... LOL

xmanberserker · Apr 23, 2013

#4: Your link is dead... LOL[/QUOTE]

http://xdaforums.com/showthread.php?t=1771021&page=25 Fixed

bradhoschar · Apr 24, 2013

Misterjunky said:
#1: If you have a Unlocked AT&T I747 Galaxy S3 you don't need any files to convert it to work on any T999 Tmobile roms.
#2: You can use any T999 Tmobile custom roms as long as you have an Unlocked & Rooted AT&T Galaxy S3 I747 Phone.
#3: There is no such thing as installing or flashing any files which would would change the frequency for 3G on a I747 phone.

#4: Your link is dead... LOL

That is not true. Before following these instructions ( http://xdaforums.com/showthread.php?t=1771021&page=25 ) I could NOT install any t-mo rom as CWM verifies the make/model before installing the rom.
Hence, me having the 'installation cannot continue' build.prop=d2att.
So, now AFTER flashing the 4 files, I was able to install 3 different T-Mobile ROMS. XTREMEPERIA ( http://xdaforums.com/showthread.php?t=2199018 ) was the only one that is giving me 4G. I know, I know, its all in the APN settings, but this is the only one that gave me truly 4G speeds with a T-Mo sim.

Misterjunky · Apr 24, 2013

re: 3G/4G

bradhoschar said:
That is not true. Before following these instructions ( http://xdaforums.com/showthread.php?t=1771021&page=25 ) I could NOT install any t-mo rom as CWM verifies the make/model before installing the rom.
Hence, me having the 'installation cannot continue' build.prop=d2att.
So, now AFTER flashing the 4 files, I was able to install 3 different T-Mobile ROMS. XTREMEPERIA ( http://xdaforums.com/showthread.php?t=2199018 ) was the only one that is giving me 4G. I know, I know, its all in the APN settings, but this is the only one that gave me truly 4G speeds with a T-Mo sim.

You are right, clockworkmod (Rom Manager) does verify, however if you select
and flash the Tmobile T999 recovery image when flashing clockworkmod recovery
all is fine.

Another thing, if you have a unlocked i747 and flash any Tmobile cwm zip file rom as
soon as it reboots and you check the network in the phones settings it will display
"T-Mobile US" and will work properly without the need of any other files or conversions.

However the Unlocked I747 will never work with Tmobile's 3G or 4G networks.

bradhoschar · Apr 24, 2013

Misterjunky said:
You are right, clockworkmod (Rom Manager) does verify, however if you select
and flash the Tmobile T999 recovery image when flashing clockworkmod recovery
all is fine.

Another thing, if you have a unlocked i747 and flash any Tmobile cwm zip file rom as
soon as it reboots and you check the network in the phones settings it will display
"T-Mobile US" and will work properly without the need of any other files or conversions.

However the Unlocked I747 will never work with Tmobile's 3G or 4G networks.

Ahh...good tip about CWM

I currently have 4g on my unlocked S3 from at&t currently on T-Mobile.

And, when I was on stock, I had 3g

Misterjunky · Apr 24, 2013

re: Tmobile Network.

bradhoschar said:
Ahh...good tip about CWM

I currently have 4g on my unlocked S3 from at&t currently on T-Mobile.

And, when I was on stock, I had 3g

Yes but when you were on stock you were on the AT&T network not Tmobile.

bradhoschar · Apr 24, 2013

Misterjunky said:
Yes but when you were on stock you were on the AT&T network not Tmobile.

No, that is incorrect. With the 4 files I flashed, I was on T-Mobile network. It was a T-Mobile ROM, T-Mobile sim, and T-Mobile radio.

EtherealRemnant · Apr 24, 2013

bradhoschar said:
No, that is incorrect. With the 4 files I flashed, I was on T-Mobile network. It was a T-Mobile ROM, T-Mobile sim, and T-Mobile radio.

Quit saying you are using a T-Mobile radio before you help someone brick their phone. The radio files are NOT interchangeable between ANY of the US variants!

bradhoschar · Apr 24, 2013

EtherealRemnant said:
Quit saying you are using a T-Mobile radio before you help someone brick their phone. The radio files are NOT interchangeable between ANY of the US variants!

Oh, my bad. I thought 'modem' and 'radio' were the same thing.

THEY ARE!!!!
Notice in the picture how under the 'phone' tab, it says MODEM.
Yes, I flashed all 4, and now have a t-mobile setup on an at&t s3.

EtherealRemnant · Apr 24, 2013

bradhoschar said:
Oh, my bad. I thought 'modem' and 'radio' were the same thing.

THEY ARE!!!!
Notice in the picture how under the 'phone' tab, it says MODEM.
Yes, I flashed all 4, and now have a t-mobile setup on an at&t s3.

You need to specify that you are using an engineering image that T-Mobile used on the 747 before the T-999 was available to test the device. In general if you flash a T-Mobile radio image to a 747, you risk losing calls and data at minimum and a hard brick at worst. It is imperative to make sure to point out that it only works with THAT engineering set.

bradhoschar · Apr 24, 2013

EtherealRemnant said:
You need to specify that you are using an engineering image that T-Mobile used on the 747 before the T-999 was available to test the device. In general if you flash a T-Mobile radio image to a 747, you risk losing calls and data at minimum and a hard brick at worst. It is imperative to make sure to point out that it only works with THAT engineering set.

Ahh...gotcha. Thats what it states in THAT OP, I just thought that once that build was on the phone, from that point on, any T-Mo anything would work. I did have the watermark on my wallpaper, but everything else said 't-mobile'.

But, yes in general, if you flash TMO onto AT&T, there be dragons.

Thanks all, and happy flashing!

EtherealRemnant · Apr 24, 2013

Even with that configuration, the only thing T-Mobile you can flash is recovery and custom ROMs. A T-999 baseband or boot loader could very well cause a brick. Its a dangerous hack because it has everyone confused. For all intents and purposes, it is 747 software with T-Mobile's AWS capability. In fact it doesn't even seem to have DC-HSPA, only HSPA+ (21mbps versus 42). It has the benefit of supporting T-Mo LTE though.

bradhoschar · Apr 24, 2013

Awesome

EtherealRemnant said:
Even with that configuration, the only thing T-Mobile you can flash is recovery and custom ROMs. A T-999 baseband or boot loader could very well cause a brick. Its a dangerous hack because it has everyone confused. For all intents and purposes, it is 747 software with T-Mobile's AWS capability. In fact it doesn't even seem to have DC-HSPA, only HSPA+ (21mbps versus 42). It has the benefit of supporting T-Mo LTE though.

Very good to know! Thanks for the info. Perhaps when T-Mo refarms their LTE, I won't have to do much to this beastly phone!

Thanks all!

:good:

EtherealRemnant · Apr 25, 2013

bradhoschar said:
Very good to know! Thanks for the info. Perhaps when T-Mo refarms their LTE, I won't have to do much to this beastly phone!

Thanks all!

:good:

It doesn't make sense for T-Mobile to refarm their LTE. The 1700 AWS band is the most efficient spectrum they currently own and the AWS spectrum is going to be the most compatible across LTE networks. T-Mobile has pretty much no chance of ever getting the 700MHz that at&t and Verizon are using.

[Q] At&t to T-Mobile

Senior Member

Senior Member

Senior Member

Senior Member

Senior Member

Senior Moderator / Mod Committee / Spider-Mod

Senior Member

Senior Member

Senior Member

Senior Member

Senior Member

Senior Member

Senior Member

Senior Member

Senior Member

Attachments

Senior Member

Senior Member

Senior Member

Senior Member

Senior Member

Similar threads

Top Liked Posts