makerpmdelta.sh script --- cut --- rpm2cpio <$FILE1 >$FILE1.cpio rpm2cpio <$FILE2 >$FILE2.cpio --- cut --- This way you loose pre/post install/uninstall scripts AFAIK. Also what about signed packages? I don't say that not having xdelta/patch like tool for rpms is a good thing, but it looks like it's not that easy...
Read the whole script, or try it! It is a working demo, and the delta files produced are of about the size you would get for a properly implemented rpm delta. It just isn't user friendly.
Michael Young