No prob dude, taker easy.
Currently I'm running team infamous's IOKP. You can grab the ROM and Gapps of there forum. You will need there wipe scripts as well.
No prob dude. I'll start you off with what I'm currently running. Its very stable and has a really good battery life.
Depends. Your battery life is directly tied to the ROM you flash, your settings. Apps you download and of course your usage. Every flashaholic is...
No prob man. Happy flashing.
Sweet. Use exactly the same steps you used to install your recovery with Odin, but instead of a recovery, flash the stock ROM .tar.
What method did you use to root your phone?
If you are not rooted, tb will not work.
Titanium backup requires root access. I use it to back up my apps when I switch ROMs. As for your data, leave any media files on your external SD...
Everything. It puts your phone to the same state it was in when you first took it out of the box.
Run the free app root check. This will tell you if you have a root problem or a titanium backup problem. Do you have a custom ROM installed?
Heads up though, this completely wipes your phone and can take over twenty minutes for first boot.
Flash the stock ROM .tar file in Odin.
Edit
Ok cool. Hit up Galaxy s2 (T-Mobile) all things root guide in this forum. This is IMO the best written guide for our phone.
