Problems downgrading to 4.1.1 firmware

I'm having some trouble flashing 4.1.1 on a 4.1.2 phone. I was linked to this site and grabbed the 4.1.1 firmware from there. I've tried both Odin 3.07 and 3.09 but I get a "complete(write) operation failed" error with both.

What's odd is this device is most assuredly an i747, yet on the phone's screen in Download Mode the Device Name field shows T999 for some reason. Might that have something to do with this failure to flash?

I was able to successfully flash a file earlier that rooted the device, successfully from the looks of it. SuperSU seems to be working fine.

Any ideas on how I can get this flashed so I can unlock the phone for use on Smart Talk?

Edit: After doing a factory reset from recovery I now get this from Odin:

<ID:0/004> Odin v.3 engine (ID:4)..
<ID:0/004> File analysis..
<ID:0/004> SetupConnection..
<ID:0/004> Initialzation..
<ID:0/004> Get PIT for mapping..
<ID:0/004> Firmware update start..
<ID:0/004> aboot.mbn
<ID:0/004> NAND Write Start!!
<ID:0/004> FAIL! (Auth)
<OSM> All threads completed. (succeed 0 / failed 1)

Larry2999 said:

Audit, coup as t be that it's got the BL for T999 which is what's causing the errors? However, wouldn't that have been likely to cause a soft brick in the first instance unless the rest of the system is compatible? I guess he could check system information under Settings to see if this really has i747 firmware or someone's previously successfully "changed" it to a T-Mob phone. Not sure that's possible but I was just thinking ... perhaps a previous J-Tag operation especially if it was purchased in the secondary market.

Click to expand...

Click to collapse

It was purchased as a refurb. Everything under System Setting - About Phone shows up as i747. Completely stuck at this point.

Edit: I just installed an app called Info that shows all relevant build information.

Bootloader version shows as T999UVDMD5
Model is SGH-I747
Build ID I747SEMC1

How can I fix this mismatch?

Larry2999 said:

That would explain it then. Thankfully T999UVDMD5 would appear to be the Bootloader for the T-Mob version running Android 4.1.2 (and not the inflexible 4.3). Have you tried flashing the 4.1.2 bootloader via recovery or, if you are feeling adventurous, the 4.1.1 version? You may find both via the links below ...

(http://www.androidfilehost.com/?fid=23269279319197288)
http://www.androidfilehost.com/?fid=23269279319197287

See also previous thread on updating bootloaders (http://xdaforums.com/showthread.php?t=2321310)

Click to expand...

Click to collapse

Tried flashing the first one from stock recovery and got:

Verifying update package...
E:signature verification failed
Installation aborted

I read somewhere that this happens when trying to flash a non-signed file in stock recovery so I installed Clockwork recovery and tried flashing both of those files. They both yield this error:

E:Error in (file path and name)
(Status 7)
Installation aborted.

Tried flashing via TWRP and get:

E:Error executing updater binary in zip (file path and name)
Updating partition details...
Failed

So apparently this phone is already unlocked. Never bought a refurbished phone before so didn't even think to try before unlocking it.

So I guess I don't need to downgrade to 4.1.1 afterall. Where does that leave me? I still have this mismatched bootloader (for the T999 model).

Am I okay to just try flashing a recent ROM like AOKP 4.4?

laith al shishani said:

Hello why you want to downgrad maaaaaaaaad

Sent from my GT-S7500 using xda app-developers app

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Click to collapse

Just wanted to downgrade in order to unlock, but it appears to already be unlocked so that's no longer necessary.

Larry2999 said:

Looks like we learn all the time. I didn't know you could install a bootloader for one system on another system and still get it to work. Thankfully your phone is unlocked. If the phone is working normally, your best option may be to leave it that way for now although, as we've seen, this could seriously limit firmware upgrade possibilities. It's doubtful whether flashing a custom ROM would help because even custom ROMs don't have their own bootloaders and still have to rely on the manufacturer's bootloader to run. A custom ROM would, therefore, probably leave things the way they are with the bootloader. I'm sure there would be a way to get this done. We just have to research a little bit more.

Maybe, now the phone is unlocked and you probably don't need the lower firmware anymore, you may try updating to 4.3 JB. At this stage, you really have nothing to lose so it may be worth trying.

Click to expand...

Click to collapse

So just try flashing AOKP or CM or something via TWRP? Don't the newer ROMs require an updated bootloader?

Edit: Got impatient and tried flashing Cyanogenmod. I used the CM Windows installer to minimize any chances of me screwing up the process. Followed the instructions, installer said installation complete, successfully installed, etc. All it did was do a factory reset. Touchwiz 4.1.2 is still on there.