How can I downgrade my OS?


New member
Dec 9, 2014
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Problem downgrading version with Odin

Hello everyone :)

I am new on this forum and I have been looking here and there alot to find out my problem, but still could not figure out what to do.

Let me explain what I aim to do:
I want to downgrade my Samsung Galaxy S3 (SGH-I747M) with Telus from version 4.4.1 to 4.1.1 in ordor to be able to unlock my device.

Running on Odin3_v.185 (Also tried on Odin3_v3.04)

So, I boot my device into Download/Odin Mode;
Connect it to my computer using USB port;
(Previously downloaded Samsung Galaxy S3 Drivers) Odin sees my Device;
I add the PDA file;
Uncheck "Auto Reboot";
Press start then:

<ID:0/003> Added!!
<OSM> Enter CS for MD5..
<OSM> Check MD5.. Do not unplug the cable..
<OSM> Please wait..
<OSM> KIES_HOME_I747MUMBLL1_I747MPCTBLL1_688429_REV04_user_low_ship.tar.md5 is valid.
<OSM> Checking MD5 finished Sucessfully..
<OSM> Leave CS..
<ID:0/003> Odin v.3 engine (ID:3)..
<ID:0/003> File analysis..
<ID:0/003> SetupConnection..
<ID:0/003> Initialzation..
<ID:0/003> Get PIT for mapping..
<ID:0/003> Firmware update start..
<ID:0/003> sbl2.mbn
<ID:0/003> NAND Write Start!!
<ID:0/003> sbl3.mbn
<ID:0/003> aboot.mbn
<ID:0/003> Complete(Write) operation failed.
<OSM> All threads completed. (succeed 0 / failed 1)

I don't know if I missed something or my .md5 file is wrong (which I downloaded a second version with same result)...

Any help will be much appreciated!!

Thank you,



Retired Moderator
Feb 12, 2012
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Re: Problem downgrading version with Odin

4.4.1 is locked to a ROM no lower than 4.4, you can't even go back to 4.3. It's an AT&T phone and AT&T (and Verizon) have arranged with Samsung to weld their devices shut (software-wise) so we can't change things (like new kernels).

The only way to get the unlock code for that phone would be to put it on an AT&T account and ask them for it after about 6 months, or look on ebay for people selling unlock codes. (Warning: if the code doesn't work the first time, contact the seller, don't keep trying to put it in. You have a limited number of tries, then it locks at another level and only AT&T [or Samsung] can give you the master unlock code to unlock that - and they won't.)