Yes. Just make sure you download I9100G firmware, he's wrong - usage of Odin is exactly the same for all I9100 variants - extract .tar.md5 file from zip you DL from Samfirmware, junk .dll file in the zip, put .tar.md5 file in PDA section of Odin, click start.
I've already given you more than enough info that you could easily have found by searching, so I won't be posting to this thread again. Up to you to fix it now...
If it's important enough to cause you grief if it's lost, back it up. No excuses
Trolling for thanks is lame
Does Samsung's auto-brightness implementation crap drive you to self-harm ? A solution !
Failure to search is the leading cause of male impotence on XDA
If you don't know how to recover if things go wrong, what are you doing flashing custom roms ?