Well, another iteration of Pierogi is now on its way up to extras-devel. For this one, I've gone ahead and rewritten the Panasonic TV protocol itself; my latest guess is that I was using a variant of the correct protocol, which only by chance happened to match the correct commands when the subdevice value was 0... Anyway, I think this version should work better. But yeah, please be prepared for bugs.

BTW, I think I know why AV2 on that TV includes an "S" -- on that photo, the first SCART port has "RGB" and "Video" labels above it (which I am guessing means it supports Component and Composite inputs), but the second one has "RGB", "Video", and "S-Video" labels. So, it would seem that the AV2 port can do more than the AV1 port can...