You should have a CWM.
1. Download and extract "CF-Root-XW_XEE_JVB-v3.1-CWM3RFS.zip".
2. Flash the "CF-Root-XW_XEE_JVB-v3.1-CWM3RFS.tar" using Odin or Heimdall.
3. Flash this kernel "Gingerbread-GT-I9000-stock-kernel+hacks.tar" using Odin or "SGS Kernel Flasher".
Can u give me guide to do that using odin....
1. Backup your data using Titanium Backup and disable lagfix.
2. Close Kies!
3. Open Odin_v1.3
4. Put the "Gingerbread.....tar" file in PDA field.
TICKED: Auto-reboot and F.Reset Time.
5. Go to Download mode on your phone:
Keep pressing "Volume down" then keep pressing "Home" then keep pressing "Power" button till appears the yellow digging android. Release all the 3 buttons.
6. Connect your phone to the PC.
(Odin should assign it a comms port which will be highlighted in yellow. It won't matter which port it is, as long as it assigns it one. If it doesn't, then you have a problem with your windows drivers and you cannot continue. You will need to remove the battery from your phone to get out of download mode).
7. Click "START".
8. OK, hopefully the flash has completed without issue and the phone has rebooted. Odin says "PASS!"
9. After totally reboot disconnect your phone from the PC.
You are done.