If you've flashed your radio manually to the KB3 radio then you can use the .zip from my previous post that contains the KB1 radio. Flash that in CWM and you're good to go. If you haven't manually replaced the radio then you have nothing to worry about.
Just installed this on top of my rooted stock GRI40: My setup was PURE stock GRI40. I had done OEM unlock in fastboot before and installed SU (and Busybox on top of stock) THIS IS NOT FOR CUSTOM ROM'S!
My steps I used
1) Copy to /mnt/sdcard via adb push (the grj22-from-gri40 update)
2) Reboot into CW Recovery
3) Do an update from a ZIP file, navigate to the grj22 update file. Note this update also patches the radio to i9020xxkd1
4) Once completed reboot - make sure OS comes up. YOU WILL NOT HAVE ROOT OR SU INSTALLED - WE WILL GET THOSE BACK SHORTLY BELOW
5) When in Android go to Settings, About Phone verify it's now GRJ22 and radio/baseband is: i9020xxkd1
6) Power off the phone go to Bootloader/fastboot. [Powered off, hold Vol Up hold and then holds power button]
10) Reboot into OS; you should now have root. You may need to redownload busybox
11) The install-recovery.sh script will still be in /etc rename this to install-recovery.sh.old to avoid recovery going back to stock each reboot. [Use Root Explorer or similar with system filesystem mounted to R/W]
After finishing you may for sanity want to go into ROM Manager and ensure current recovery is still set (in case you power off since replacing recovery)
NOTE: Google Talk Installed by this image will have the video support right away, no need to download anything else. WORKS really well ; if you have no one to talk to on another Android device - you can chat/video chat to PC's or Mac's with the gmail Google Talk plug in installed