Here's a list of firmware updates that has been released by Bell Canada Network Provider for their own Carrier Branded Samsung Galaxy S II GT-I9100M. The list may not be complete yet, but this may helpful in providing some brief details regarding your Galaxy S2 firmwares that are currently available.
Kernel version is: 126.96.36.199-19100XXKG2
Build number: GINGERBREAD.UGKG2
Product Code: GT-I9100LKABMC
Samsung Galaxy S II Bell Canada Stock ROMs and Modems - These are the available stock ROMs that can be used to manually flash the device if you need to return or flash back to it's original Bell stock and modem, just in case you need warranty.
Firmware info: PDA: I9100MUGKG2 Phone: I9100MUGKG2 CSC: I9100MBMCKG2
I9100UGKG2 Stock Kernel:Kernel_I9100MUGKG2.tar
Directions: Place .tar file in PDA section using ODIN
Stock Bell/Virgin Modem
Directions: Use Odin and place .tar file in "phone" section
Directions: Flash with Odin in CSC section
Some users are experiencing better Gps/Reception with the KH3 modem
Directions: Flash with Odin under "phone" section
How to check the firmware version on Samsung Galaxy S2.
Type this code on your Galaxy S2 dial pad *#1234# and then you will get the firmware info.
How to Update your Samsung Galaxy S2 Bell firmware via Kies server
All you need to have is Kies installed on your PC. Using the USB cable, connect your phone into your PC, when your phone is already connected the Kies application will launch automatically, if Kies doesn’t do that just open it manually in your PC. Go along with instruction to update your smartphone, and then Kies will do the job in searching appropriate update for your Galaxy S2, when found the update let Kies update your phone.
The above firmware links was compiled by Intratech, you can visit his thread at XDA-developer
on how to use the above stock ROM files in flashing your Galaxy S2. Firmware Flashing, rooting and unlocking can be found and was posted by KayvinM here.