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[Q] How to Network Unlock Galaxy S3 sgh-T999

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etrash310
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Default [Q] How to Network Unlock Galaxy S3 sgh-T999

I'm a bit of a noob, so apologies if this is in the wrong section. I've had a very difficult time finding threads that focus on those who have (stupidly!) applied the OTA 4.3 jellybean update, and what they can do to network unlock the phone. So here goes:

Samsung Galaxy SIII
SGH-T999
Android Version 4.3
Baseband Version T999UVUEMJC

Stock build. No root.

The closest step-by-step I've come across:

Remove T-Mobile SIM. Replace with ATT SIM. Reboot phone.

*#197328640# which successfully puts me into service mode.

This brings up the following menu:

MAIN MENU
[1]UMTS
[2]CDMA
[3]LTE
[4]SIM

From there its
[1]UMTS
[1] DEBUG SCREEN
[8]PHONE CONTROL
[6]NETWORK UNLOCK
[3]PERSO SHA256 OFF ...

Now, that's as far as I can get. The guide then says to go back to [6] and there should be an option, [4] NV INITIALIZZ.

This option is not there for me. (Note: at this point the PERSO SHA256 status is indeed set to SHA256_ENABLE_FLAG [0]).

Another guide suggested BACKing to the MAIN MENU and selecting option [5] run EFS SYNC() after selecting [3]PERSO SHA256 OFF.

I have done this and the screen reads: SYNC success. please reboot.

I do so, heart aflutter... only to be met with a SIM unlock PIN code entry screen.

Unlock fail.

Other threads have suggested downgrading to 4.1.1 in order for this to work and the necessary options be made available. Most of what I have read has said that attempts to downgrade from OTA 4.3 (with big brother KNOX) will result in a hard brick.

So, if you've made it this far... Has anyone figured out how to SIM unlock this particular phone running OTA 4.3 without rooting/downgrading?

If there is a more suitable thread discussing SIII's that are running 4.3 please direct me there.

Many thanks!
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Perseus71
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You could try and flash a 4.1.1 Modem. After that, try the above process.

Note - In that process, you are required to be super patient at each step.
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etrash310
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Quote:
Originally Posted by Perseus71 View Post
You could try and flash a 4.1.1 Modem. After that, try the above process.

Note - In that process, you are required to be super patient at each step.
Appreciate the response.

Yes, most of what I have come across has indicated that I would need to get 4.1.1 by hook or by crook in order to network unlock the phone, having upgraded to 4.3.

I have some experience fiddling with such things, but many posts have also indicated that, with the new KNOX package in tow, backing down from 4.3 will hard brick this device. I am hoping that, with access to Service Mode, someone will discover a way to network unlock without root/flashing.

Thanks again!
 
Perseus71
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Are you Rooted ? If so flashing the LJC modem from Doc's thread won't brick your device.
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etrash310
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Quote:
Originally Posted by Perseus71 View Post
Are you Rooted ? If so flashing the LJC modem from Doc's thread won't brick your device.
The phone is not currently rooted, no. Most rooting instructions I've seen are for 4.1.1 or 4.1.2. My guess is I'm going to have to root to unlock...

Could you direct me to instructions for rooting OTA 4.3?

Again, many thanks for taking the time to help.
 
Perseus71
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Quote:
Originally Posted by etrash310 View Post
The phone is not currently rooted, no. Most rooting instructions I've seen are for 4.1.1 or 4.1.2. My guess is I'm going to have to root to unlock...

Could you direct me to instructions for rooting OTA 4.3?

Again, many thanks for taking the time to help.
Follow these. Effectively Flash Custom Rom using ODIN then flash SuperUser Zip.
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