[Q] Unlock AT&T Galaxy S3

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Mar 22, 2011
5
0
Hey guys,
I have an ATT Galaxy S3 but I recently switched to TMobile. I don't have the sim card yet, hopefully get it tomorrow, but my ATT sim card has been deactivated. Since I need to unlock my phone to use Tmobile, I was looking at some forums and I could do it using the dialpad and pressing *#197328640# and following some steps. But I read that this was possible in only a 4.1.1 ROM?

Right now I have MIUI v5. Do I have to downgrade in order to use the *#197328640# code and unlock?

Cheers!
 

audit13

Inactive Recognized Contributor
Jun 4, 2012
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Toronto
You must be running stock 4.1.1 in order to have the necessary menu options.
 

theramsey3

Senior Member
Jun 27, 2012
355
167
Have you ever been on the 4.3 OTA? Or the 4.3 bootloader? If you haven't been on them you can use Odin to go back to 4.1.1 however if you have the 4.3 bootloaders and you try you will certainly have a hard bricked phone that might be recoverable via SD card or you will need a jtag.

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