Just happen to be “in town”... here is what I did: almost nothing.

I have a work-around. I created a macro that does "device up" then "enter". That 90% of the time "toggles" between my two inputs. Yes, I only have two inputs to choose from (Tivo HD on HDMI-1 and DVD on HDMI-2), but in true Mits fashion, you can remove all but three unused inputs. So if I hit the device button, I have three options show up -- one being "cable in" which I do not use. So, in sum, 90% of the time the macro toggles correctly between the two inputs I use. 10% of the time it selects the unused input I cannot disable.

Really, the proper solution is a direct code to directly select HDMI-2, like there is for HDMI-1. And, the ability to turn off the unused 3rd input would make sense. All of this is simple firmware tweaks, which is something implied could be done via the "SW upgrade" option within the TV menu. But that will never happen, I'm sure, since it is also implied only a technician can do this procedure (ie, code not given to consumers).

Good luck!