This is one of the points I'm most interested about, I Think you cannot debug the Japanese releases and I think these ones have the most potential for having unused characters hidden in the data. I have a hunch the V3 exclusive characters (Teketchi, Warusotchi...) were discarded characters for the Keitai series or the EnTama the way V2 characters were discarded V1 characters (Toratchi, Whaletchi, Flowertchi...).
But of course, there's no way of knowing that. Or if there were more discarded characters.
Hmm, that's a good point. I think the Keitai can be debugged using soldering as I recall? There's definitely a debug jumper that's a rectangle shape rather than a circle shape on some Keitai boards. As I recall, there's also one of these on some 2.0 European V1s too, though I'm not sure they've ever been successfully debugged.
There is also the question of how many characters might be present in the data but not
in the debug character select. One prime example is Tsutatchi / Tsutayatchi, which is very much a selectable character on the Plus but behaves differently on other V1-3 versions. The food the character eats - and presumably any other character-specific behaviours - seem to have remained unchanged between the versions, but its sprite set uses Nazotchi's sprites instead, hence there being two Nazotchis in the debug character list. However,
the only thing that seems to have changed is the set of sprites that the character points to, rather than the sprites themselves, as the sprites can still appear when other Deka characters use items on V2/3 (due to the Deka characters having limited sprite lists, I guess there's an overflow and it reads the sprites for a different character instead).
While logging Deka sprites, MasterPengo also noticed that some V2-exclusive sprites appear when certain Deka characters use certain items, too. After a lot of research I found that this is due to a bunch of sprite IDs seemingly not getting replaced by other sprites on the V3 - rather, new sprite IDs were added to the end of the sprite index list. What this basically means is that there's a few IDs for every character that aren't used because they correspond to sprites that would have only been used on the V2. A few of these are still a bit speculative:
27 - Skateboard 1
28 - Skateboard 2
29 - Boots
30 - Tools 1
31 - Tools 2
36 - Cape 1
37 - Cape 2
46 - Racquets?
64 - Computer 1?
65 - Computer 2?
70 - Glasses?
So the next question is whether new characters have totally unused sprites in these slots that would have been used should these items have stuck around, or whether the V2 sprites are still in these slots, even for characters that weren't in the V3. A dump would help answer that question.
I also want to figure out the growth charts, because the ones from the V2-V4.5 are kind of a mess. I think I figured most of it out by now but having the code would help a lot.
Totally, yeah. It'll be nice to finally determine once and for all what the required conditions for "good care" is, haha.
Me too, at this point I would even be willing to sacrifice Tamagotchis that are already broken (in ways that don't affect the ROMs) to extract the ROMs if necessary, too.
Lots of broken Tamagotchis come up every now and then on eBay and a few other sites. I know a few people interested in figuring out how to dump the connections have had their eyes on some of those listings to experiment with, so I hope one of them ends up giving us a positive result. Especially if it's a lot with a bunch of different versions and we can get them all dumped in one go, hahaha.
If they do get dumped I hope the code is like... readable, you know. It'll be important for both preservation and research purposes that the dumps are catalogued by their ROM version numbers; if the ROM versions aren't obvious (since I don't think they're stored as separate graphics like they are on the Tama-Go and Friends) it'll be that extra bit trickier knowing which version has been dumped.