Originally Posted by toxicated2
I was thinking of using root_66 firmware for t999 will i end up locking the phone or will it work in indian network carriers after flashing tmobile firmware ?
Sounds kinda like some of the "frankenphones" we've heard about over the last several months. Or it could also be a fake/chinese knock off. If I were you, I would see if there were any way to send it back to whoever sold it. If you plan to keep it though, understand anything you do is AT YOUR OWN RISK! The only absolutely safe course of action is to do nothing to it. If you try to flash it via Odin, and it allows it to flash, but you chose the wrong firmware, it WILL brick. There is honestly no possible way to know for sure what is up with the device.
If I had to guess, something is lying to you about what you are running. If your current firmware version is from an I9300, then that is most likely what you have. That firmware WILL NOT work on any Qualcomm, US model S3's. This tells me that its probably an I9300, and someone screwed with something, (or was careless when trying to copy Samsung), in the bootloader. Because it tells you it is a T999 in download mode, it will probably not let you flash the I9300 firmware. But if you try to flash the T999 firmware, there is a very good possibility you will brick it.
It is up to you what you want to try, but understand you are taking a bigger than normal risk since you already know the device isnt normal to begin with.
One way you can try to determine what motherboard it uses, (though this is by no means a for certain way to know), is go to the SIM unlock thread in General and try to follow those instructions. Also try the GPS fix thread in the Q&A sticky roll up. If I am not mistaken, both use dialer codes that are specific to Qualcomm devices. If they work, its a better chance of it being a T999. If they do not work, its more likely to be an I9300.