Default [Q] where can i download firmware version 4.1.1

Hey everyone, I have an At&t Note 2, sgh-i317 that I am trying to unlock. It is currently running 4.3 and tried to do the unlock several times, but have realized I need an older version in order for the correct options to appear in the unlock menus. However, I am getting stuck trying to downgrade to 4.1.1 cause I CANNOT find a firmware download for 4.1.1 and have spent awhile looking. Anybody have a direct link to 4.1.1? Thanks

Also, in a walkthrough to downgrade firmware, it says I need to "Enable the USB debugging option by
pressing Menu > Settings > Applications. Then navigate and strike on Developer Options to ensure that the USB Debugging is enabled." How do I do this?

Answers to either of these questions would be appreciated, or if someone has a good, in depth walkthrough to downgrade to 4.1.1, I would greatly appreciate it.