Apparently you can unlock all the support conversations by editing your system savefile with a hex editor, thats all I know since the person who did it can't reveal it yet since they have a deal with a YouTuber that won't allow him to reveal it
@Falo is it possible you can take a look at the system savefile? Apparently if you look at the lowest part of the savefile there's a way to unlock all of the support conversations. I was able to get in contact with the person who was able to do it but they can't reveal much yet as they have a...
I'm asking this because someone on YouTube is claiming that they hacked their savefile to unlock all the support conversations, I don't know how they did it
@Xdqwerty, Osu! Tatakae! Ouendan! is the Japanese version of the game, different settings/characters/songs but otherwise identical mechanics. I played that before I knew about Elite Beat Agents lol. Both fantastic games https://en.wikipedia.org/wiki/Osu!_Tatakae!_Ouendan