I figured out the proper way of displaying the boot menu. I made codes for the 2 menus that work (the STANDARD DEBUG ones) in the first post.
I'll keep searching for the Yoshida menu, but probably not today... 3 debug menus in 1 day is pretty good, I think. Fun fact: there are 3 people named Yoshida in the credits. It looks like 1 was a programmer and the other 2 were card illustrators.
Edit: Also that was a typo, it should have been text index 0x58f, not 0x5f8, not that it matters now.
January 21, 2013, 06:19:58 pm - (Auto Merged - Double Posts are not allowed before 7 days.)
I'm starting to think that the Yoshida menu was removed, or at least it's beyond my skills to find it. It has a text index of 0800, which is way to common a number to search for in the rom. I tried some other debug text but my method of searching for clumps of debug text isn't working anymore. In fact I'm starting to think some of those text indices aren't used at all, and that the matches I found were just coincidences. If that's true, their corresponding menus were probably removed.
What's more, I have no idea where the Shinario menu fits in. For anyone who's curious the function's address is 11:49a8. A search for a849 (after byteswap) brought up only one result, which was also in bank 11, but I can't tell if it's a coincidence or not. But it looks abandoned, not invoked from anywhere. The shinario debug menu is probably completely separate from the other menus, and I bet the Yoshida menu is too - or, was. In any case, it's about time I made a shinario code for whoever's curious. It has the handy ability to change the cards you have.
I'm still going to be hacking this game so maybe something else will turn up, but I think I'm done looking for debug menus unless/until I find a new lead. Thanks for your help and interest, danke.
Edit: made some new codes which don't replace the entire menu. Screen is cleared properly before the Shinario menu now.