Install latest I9100XXKH3 Firmware Android 2.3.4 Gingerbread on i9100 Galaxy S2 (SII)

I9100XXKH3 firmware installation procedure is given here.

Downloads

• Samsung USB Drivers , Download 
• I9100XXKH3.rar Password - samfirmware.com | Download 297 MB
• Odin software Download
• Make sure that phone is well charged

Step 1

1. Install the Samsung USB drivers
2. Unzip the main firmware file and get following files

CODE_I9100XXKH3_CL479037_REV02_user_low_ship.tar.md5,
EFS_I9100XXKH3_CL479037_REV02_user_low_ship.tar.md5,
GT-I9100-CSC-HOME-MULTI-OXAKH3.tar.md5,
GT-I9100-CSC-MULTI-OXAKH3.tar.md5,
KERNEL_I9100XXKH3_CL479037_REV02_user_low_ship.tar.md5,
MODEM_I9100XXKH3_REV_02_CL1050544.tar.md5,
u1_02_20110310_emmc_EXT4.pit

3. back up the phone
4. Shut down Samsung Kies
5. Install Odin3 v1.85 and run it
6. switch off the device

7. Hold Volume down key+ Home button key and press power on and accept the screen following it
8. Connect phone to  USB

9. You will get the message “Added! !” under the Odin’s message box 

10. Check only Re partition, Auto reboot & F. Reset time in option

11. Put these files like this in Odin:

PIT = u1_02_20110310_emmc_EXT4.pit,

PDA = CODE_I9100XXKH3_CL479037_REV02_user_low_ship.tar.md5,
Phone = MODEM_I9100XXKH3_REV_02_CL1050544.tar.md5,
CSC = GT-I9100-CSC-MULTI-OXAKH3.tar.md5

12. Hit the start button to start the process

13. when phone gets restarted disconnect it from usb

Thanks to Samfirmware.com and dialandroid.com for the tutorial