We have been using LP1 Repack as a stepping-stone between Gingerbread and custom ICS Roms so far. Now there is an easier way.
The following procedure was tested by thechints, vviz, abhisahara, and chasmodo of xda developer forum and it works.
It was tested on Stunner and CM9, but could work for any ICS Rom that currently has "flash LP1 Repack" as one of the steps in its flashing instructions.The suggested method is safe sofar as it won't brick your device. You have a safe way back to GB via nAndroid backup or PC Odin if it fails.
The only tool that you need for the following procedure to work is AbyssNote 4.2 Kernel.
Get AbyssNote 4.2 kernel HERE.
Do not use earlier AbyssNote Kernel versions for the following procedure.
So, how to do it?When on any rooted GB Rom:
Do not put faith in the fact that your Titanium Backup or some other root app works.
Do not use various root checkers from the Market.
Some users have managed to achieve soft-bricks while still on GB. They tried to flash AbyssNote kernel and got stuck. Do not let that happen to you.
1. download AbyssNote 4.2 kernel and place it on your internal/external SD Card
Also download the ICS Rom you want to install and put it on your SD card.
2. reboot to CWMR (press and hold volume up + home + power button) and do a backup of your current system
3. after your backup is done, stay in Recovery
4. go to install a zip from SD card --> select AbyssNote 4.2 zip and flash it
5. go back to CWMR's root menu --> advanced --> reboot recovery
6. you'll find yourself in AbyssNote's Touch Recovery (select options by tapping them, not by using the volume rocker and home button)
7. factory reset --> wipe cache --> wipe dalvik
9. flash the ICS Rom of your choice
10. reboot and let the Rom settle for a couple of minutes
Now comes the important part...check if you have root.Start any Explorer with root permissions (Root Explorer, Es Explorer, X Explorer etc.).
Copy any file (a picture, txt file, MP3, whatever).
Navigate to /system folder
Change the /system folder's permissions to R/W.
Paste the file you have copied into /system.
If the pasting goes through OK, you're fully rooted.
Delete the file you've just pasted and set /system as R/O again
And that's it. Enjoy your rooted ICS Rom.