You must know how to use odin! [If you dont know, dont worry, its easy]
Optional, root your phone make a full backup of your data/apps with Titanium Backup.
Go in download mode (Vol down + Home + Power or from the power menu).
Open Odin, click reset files, select ops, tick one package and select the "Flash_this_as_one-package.tar" file.
Click Start. The phone will reboot in recovery. WIPE DATA! (The wipe process may take a minute+, dont worry. The boot process may be long too, but dont worry its normal!!)
Optional, Enable Hybrid Data2sd [More space for apps!]
- Make a backup of your sdcard, enter CWM recovery and go to Miscellaneous => Partition SD Card. Choose the sizes you want (Recommended:512-1Gb ext, and 0mb swap]. After the partition completes, wipe data and reboot. You can now copy back all your sdcard files which you did a backup.
- Then copy the contents of the sdcard folder in your sdcard and reboot. No wipe data required, the first reboot may take time.
- Install titanium and go to titanium backup's preferences, and select Restore Backups to => Internal Storage. Then do your restore...
Enjoy!!