its quite involved... I'm trying to make one that is compatible with my deodexed ROM but its taking quite a while.... Many many many system files get patched in the update....
I updated then backed up and made a ROM from it and extracted all the /system files that were shown to me different in winmerge. and then deleted the sections that patch /system in the update script and left the firmware updates then i added the new updated deodexed system files.... but i'm still having trouble getting it to flash correctly and when i get it to it sometimes freezes me up... Once i get it booting properly then i have to re-edit all my system MODS (e.g. 4-way reboot etc...)
working working working....
I've been at this since the update downloaded today on my phone... these touchwiz systems are waaaay too BIG they take a long time to copy, a long time to check, and a long time to install.... I miss AOSP