Guide to update/root from Bell KG2 (2.3.3) to KI3 (2.3.5)
Hello all,
I recently bought a Samsung Galaxy S2 from Bell Mobility and it gave me KG2 with 2.3.3, and the battery life honestly sucked... but after reading posts on this forum ppl were saying they're getting amazing battery life after KI3.
So I went through the forums, read stuff about how to upgrade, root, etc etc, and tried it. Although I still cannot comment on battery life as it hasn't been long but i'm pretty sure its definitely better than what I had previously, the KG2. Im a heavy user (always texting, phone calls, browsing) and i'd be happy if i barely get a whole day

lets see..
But i've complied a guide using steps already written in different threads on the XDA forum. I just made it simple for Bell users who want to upgrade maybe for a better battery life.
Updating and Rooting Samsung Galaxy SII from 2.3.3 to 2.3.5!
From KG2 on 2.3.3 with Bell Mobility
Mostly used: forum.xda-developers.com/showthread.php?t=1075278
1) Put the phone into download mode (Power + Home + Vol. Down)
2) Start Odin - Click on the PDA button and browse to the .tar file. (In my case, GT-I9100_XEU_I9100XXKI3_I9100XXKI3_I9100XEUKD1 - 2.3.5)
3) Connect the USB cable and wait for the ID:COM section to turn yellow
4) Click 'Start' to flash. Do not disconnect the cable or turn off the device, it will reboot when it finishes.
5) You are now on 2.3.5 I9100XXKI3.
To Root the Device:
1) Put the phone into download mode (Power + Home + Vol. Down)
2) Start Odin and click on the PDA button and select the insecure kernel. (In my case, GT-I9100_XXKI3_insecure)
3) Once you've done this attach the USB cable to the phone and once ID:COM turns yellow click flash. Don't remove cable or press anything, it will reboot when it's done. You will see a yellow triangle when it reboots, fear not it's to be expected. Remove the USB cable when the phone reboots.
4) After the phone reboots go to: Settings > Applications > Development and check USB debugging if it's not already ticked.
5) Run S2 Root application and connect your USB cable to the phone
6) Press 'Root' and wait for it to finish.
7) You could now flash the stock kernel to get rid of the yellow triangle at the boot screen.
8) Follow the same steps required to root the device, and instead of selecting insecure kernel, choose original kernal (In my case, GT-I9100_XXKI3_original)
9) You've now rooted the phone and put back the stock kernel! Enjoy!
After this, I installed a custom KI3 ROM, specifically the
GT-I9100_WanamLite.Deodexed.Stock.KI3.V3.0.NO-WIPE
using CWM in recovery mode
Lets see how it affects my battery life
Experts and Professionals, please comment if I wrote anything wrong here.