Alright thanks. Yes I have just read about "stock android" and "skinned android", although I suppose it can also be called "default operating system". Even "stock android" seems to have more than one meaning- on one hand it can mean AOSP before putting Google and manufacturing company stuff on it, and on the other hand it can mean what you pointed out, as in "flash stock android before installing a custom ROM". Lots of new terminology and the custom ROMs game has been around so long there is tons of old and outdated methods and information. Now reading about A/B partitioning... so much left to learn!