How To Add HPS Files to 20XX 4.0
(this requires GCR and rebuilding the ISO with checking "do not use game.toc")
This is current last song 20XX 4.0 Beta01.
But we can add more!
1) Obtain an HPS file of your liking.
2) As shown in the above screenshot, the last named file is 68.hps. We are adding another one. So increment the HPS name counter by one. In this example, I would rename my HPS file 69.hps. (The numbers are in hex. So after 69 comes 6A, then 6B, .... , then 6F, then 70, etc.)
NOTE: Letters within the file name ARE capitalized!
3) Extract a root folder of your 20XX 4.0 ISO with GCR (at this point, you should probably just have a "master 20XX root" on your desktop or something).
4) Navigate into the "audio" folder and paste 69.hps
5) In your 20XX root folder, open MnSlChr.usd in a hex editor.
Go to offset 0x003edda8. This is a table of pointers. You don't really need to know what these actually do, but just go down to the very end and add one more entry (because you are adding one song). For your new entry, take the last entry and subtract 0x20.
6) Now we need to add the song name ASCII text that will appear in the debug menu. In the step above, your new entry was "0x80fd9da0". Subtract 0x80bec720 from the new entry value. (In this example, 0x80fd9da0 - 0x80bec720 = 003ed680). Take the result and go to the offset in MnSlChr.usd.
7) Add your song name (ASCII to hex conversion). 31 character max.
8) Save MnSlChr.usd. Rebuild 20XX 4.0 ISO with GCR while checking "do not use game.toc".
9) Major profit.
Yes, you can go all the way up to FF.hps.