I don't know what my scores were, exactly, but I can take an educated guess and say low 500s (maybe even 400s) when my fully secured BoA card unsecured a few years ago. In the current credit climate, I don't know that they are/aren't going to change their criteria, but my guess is that they look at your internal history to determine whether or not to unsecure. They'll probably look at your overall credit profile and score to determine if they'll give you a CLI & how much, upon unsecuring.
But, this is all my opinion. Keep us posted so that we find out the answer!
