It works! After several hours on the phone with MItsubishi, they agreed to send me the software upgrade and I now have an HDMI2 code! They did not want to let me have the upgrade because they only want to give it out if you are having one of the particular problems it addresses. The first level techs only knew what was in their database so I asked if I could make a specific inquirey. I was transferred to a higher level tech who was actually familiar with the Pronto and acknowledged that there was no discrete code for HDMI2 and that the firmware upgrade did have it. After a good bit of cautioning about installing the new firmware if I did not have the specific problems addressed, she consented to sending it to me, overnight no less. So far, the TV has not freaked out and I now have a discrete code for HDMI2. I post this depth because I noted that others have asked similar questions of Mitsubishi TVs in other forums.
So now I can go back to trying to progam the remote (a few hundred more hours).
