A Reddit PM from a South American Reddit user who got the disc along with several other discs with a Wii indicates that the System Menu on the Startup disc was DIFFERENT from any released one. He dumped the disc, but he lost the dump and the disc itself, unfortunately.
However, these old Wii screenshots, based on his details, seem to be part of the unique System Menu only on the Startup Disc, meaning that we HAVE OUR FIRST SCREENSHOTS OF THE CONTENT OF THE DISC:
So, there's already a thread for this, but it's kind of stagnant and it's in the wrong section because it's based on an outdated theory that this isn't actually lost. Since I've determined that it is, and there are still several mysteries to sort out about it, I figured that I'd make a new thread.
So, since the NAND was dumped and released here on LMW, a Wii homebrew guy dumped all of the images from the NAND image and put them on his site. While most of the stuff there is already known and documented, there are a few mysterious files.
The first mystery is a set of files starting with "frame8_" which appear to be the corners of an unknown objects, with filenames identifying their positions (such as frame8_lb for left bottom). I'm not really sure what this could be or is used for, so I would appreciate if someone could help figure this out.
The next one is an image called squareWhite. It's a white square. That's all I know. It might be used as a background image or something (tiled), but I'm not really sure.
The next one is an image called discIn, which is just a white slash-type line. My best guess is that it's supposed to be the disc flying into the console as part of an animation, but there is no such animation that we know of and there's no reason why they'd play it again when the Startup Disc is detected.
Upon my own examination of the NAND, I have noticed several files that would appear to build the rest of what is missing, however I cannot open them. These seem to be the animation files for each of the screens, however there is also a mysterious animation file labeled with "wait" instead of a message name.
Upon examination of the Startup Disc menu binary, I have discovered that the filenames for the 3 colour bases are baseOra, baseRed, and baseBlue. This confirms that there are no other colour bases, however I have not found the actual files, just the references in the binary.
I tried to run the NAND on Dolphin again, as a recent revision allows detection of update partitions (aka the Startup Disc), however this new revision also adds files to the NAND which causes it to break, so I will have to contact a Dolphin dev before proceeding here.
As for how to find the actual disc, the best leads would be tracking down old Wii kiosks from launch era, as they may still have the disc in/with them, however I don't have the money or resources to do this, sadly.
Another odd thing is that a Wii SDK document (available on the same site as the Startup Disc images) - pokeacer.xyz/wii/pdf/Wii_Terminology_v03.pdf mentions the Startup Disc in a changelog for an older version, however there is no mention of it being removed, and it is not present in the current version. I have attempted to track down older versions of this document and older SDKs, but with no luck unfortunately.
So, post all insights/comments/etc. below, and feel free to keep searching for this disc and more info about it!
There is no "Startup Disc manual", at least not one that any customer would have. There were probably instructions for it for the retail kiosk people, however. There might be a variant of the Wii manual with Startup Disc stuff in it, which is what I'm looking for, but it's not a "Startup Disc manual" per se.
Update: I found what I really wanted to know- I've abandoned this search.
What did you want to know?
Okay, let me explain what happened. The new text put the status of the disc in a strange place- even LoserAtFinding (admin here) couldn't tell if it was lost or found. As such any search efforts are on hiatus. Check my thread in the Found Media section.
Well, that depends on if there were segments in between the episodes. Just because King Koopa's Kool Kartoons is a repackaging of the same cartoons doesn't mean I don't want to see more of that horrible Koopa Kostume. The same applies here.
Edit: Nevermind. Apparently there were no segments.
Speaking of King Koopa's Kool Kartoons, I actually remember reading about it on MarioWiki years back, didn't know it was lost until recently when I saw it on LMW.