1) I have never set a password on this device
2) I have never installed ssh on this device

I used becomeroot w/o a password many, many times last week. Just used it again for the first time since then, and this time it asked for a password.

Very strange.

EDIT:

Just checked my other N810, on which I'd installed becomeroot at about the same time last week. It also didn't require a password then, but now is (also unknown).

Diablo bug???