Thanks a lot Neil.
My 660 is very old, yes. But still I can't find any model at the moment as an upgrade for mine.
Lower current models are still below the old 660 functionalities. So I think I'll rely on it for a while longer...

I recall that a couple of years ago, when Garmin released 2X5 series, a few older nuvi could be converted. I was looking for anything regarding the 660 without success at that time.
I really thought your great table could match...

Sorry for stressing the subject out... Is there any ways for me to check the PCB P/N? Maybe on my unit... or maybe something that could help a newer donor firmware unit?
(lol... I'm trying my best to keep hold of my unit... but... it seems it won't last much longer...)