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Thumbs up [Q] At&t to T-Mobile

OP bradhoschar

22nd April 2013, 11:13 PM   |  #1  
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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!
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23rd April 2013, 12:05 AM   |  #2  
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Quote:
Originally Posted by bradhoschar

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.
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23rd April 2013, 12:30 AM   |  #3  
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Quote:
Originally Posted by Okaham

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.
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23rd April 2013, 12:40 AM   |  #4  
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Quote:
Originally Posted by Okaham

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 ----------

Quote:
Originally Posted by bradhoschar

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|
Last edited by Da Kine; 23rd April 2013 at 12:45 AM.
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23rd April 2013, 12:35 PM   |  #5  
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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://forum.xda-developers.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.
Last edited by xmanberserker; 23rd April 2013 at 09:16 PM.
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23rd April 2013, 01:38 PM   |  #6  
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23rd April 2013, 08:14 PM   |  #7  
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Wink re: Hmm
Quote:
Originally Posted by xmanberserker

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://forum.xda-developers.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
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23rd April 2013, 09:17 PM   |  #8  
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#4: Your link is dead... LOL[/QUOTE]

http://forum.xda-developers.com/show...771021&page=25 Fixed
24th April 2013, 01:15 AM   |  #9  
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Quote:
Originally Posted by Misterjunky

#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://forum.xda-developers.com/show...771021&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://forum.xda-developers.com/show....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.
Last edited by bradhoschar; 24th April 2013 at 01:17 AM. Reason: Misspelled word
24th April 2013, 02:22 AM   |  #10  
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Post re: 3G/4G
Quote:
Originally Posted by bradhoschar

That is not true. Before following these instructions ( http://forum.xda-developers.com/show...771021&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://forum.xda-developers.com/show....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.

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