Here is a breakdown of the facts:
I have a SGH-I747 (Canadian version)
I wanted to unlock it so I downgraded and installed 4.1.1 (I747MUMLL1)
After, I realized that the 4.1.1 is outdated and don't like the layout...etc.
Now, I want to go back to 4.2.1 or 4.3.
What are the steps to install 4.2.1 or 4.3 ?
Do I have to root the phone before installing anything?
Any help would be appreciated.