Well I thought a "sync" through PC Suite would allow for recovery. But nope. Phone overrode the contacts saved on the computer. (I loved N900, like N9, but so miss Palm syncing software.)

I've got a couple months old backup (which is most of my contacts anyway) on my N900 (and of N900 on the computer) and I suppose I could sync the two phones somehow - but I need to do this first. It would recover most of contacts and I can deal without chat history. And chats and contacts are really the only things affected.

So if recovery from the N9 itself is impossible, it is is not a catastrophe... just an enormous headache!