well, you are right about one thing - after checking, the sdk repo was enabled... not sure where that stroke of stupidity came from!

nonetheless the result of your command was not as to plan:

I suspect a re-flash would be the easiest way to fix, but since I've just got the tablet working more or less exactly as I need, perhaps I'll just forego updates in lieu of having to re-install all my apps.

then again, I'm still way open to having my ignorance paraded in front of me, so any suggestions would be appreciated. thanks