I think they will have to make a hardware change to properly support lithium primary cells. It is easy to make a firmware fix to accomodate batteries with a lower (than nominal) voltage; the problem, as I see it, is they didn't allow for the nominal voltage of the regulator/circuitry to be higher. If it was just firmware they could have done it ages ago. Gotta wonder why they didn't change the hardware when they went to the "x" series even.

Garmin's "solution" (on their site) to lithium batteries is to discharge them a bit first. Yup, that's why we pay the big extra $$ for them...doing better sitting on the shelf is nice, but we kinda rate a lot of things by how they do when we're using them. Modern quality alkalines have a very long shelf life already.