http://teknoparrot.link.free.fr/multi/EZ2AC-EndlessCirculation.html

As the arcade releases of EZ2 seem to be well and truly over, recently in my spare time I have been investigating how to add extra song entries into EZ2AC. The tool is mostly fleshed out for use with FNEX, but also supports reading the bin files since EV - don't expect it to work well though. The bin file went through a few revisions with different formatting up until FN. So officially I'll claim it only has compatibility with FNEX.

Now to preface. Note that that I specify entries and not songs themselves, there's still a fair amount of manual work required for adding completely new songs. this does not mean any sort of omnimix or custom song packs anytime soon. The actual chart data is still a bit of a mystery to me, the devs changed the format a little in each version since EV, I assume to fix some limitations the old format had and i'm yet to work out what the differences mean. All my testing was done by using some songs in the data that were unused (more on this below..) or by adding in CV2 and course exclusive songs to normal modes. The few songs I tried bringing forward from NT and EV, play okay for a bit then start to break (missing notes or super long long notes) or just crash the game.

Sorry for the following wall of text/blogpost but I want to explain what I've done and how it works. Downloads are the bottom.

So, what does this tool actually do? It allows you to import an encrypted EZ2AC song.bin file, and view/modify its contents. Saving the file saves it in its encrypted format, so you don't have to mess around with decrypting and re-encrypting. After patching the exe and then updating the stage.ini file with the new entries they should appear in game, this is manual for now, but I plan to make this last step somewhat automatic in the future.

Cool right? Well, unfortunately that alone wasn't enough to have extra song entries work in the game. I think around EV, the exe starts hard coding the amount of songs it can load, and it also loads this data before some pretty important sections in memory, so even if I patched the song limit, adding extra entries started to overwrite other memory, causing weird graphic issues or outright crashing. This was the a big road block and I thought the dream was over...

Fortunately(?) I had an unhealthy obsession, so I kept digging and trying different things, and finally for FNEX I think I solved it. It turns out there's a huge chunk of memory that looks like it goes completely unused, so I thought, why don't we just make the game load the song data here and redirect all the offsets to point to there instead? So I spent a stupid amount of time working out all the offsets that I needed to change (I'm sure there was an easier way to do this), and... it worked! It took a while but I could finally add more entries than the original, and after fixing some final issues with loading CV2 mode, every game mode now functions perfectly with a patched exe. I have yet to find the limit on the amount of songs you can add, I think the most I tested was 40ish - that's enough for a omnimix if anyone ever works out chart conversion.

I added the function to patch the exe in the tool, so after you make your changes, you can select "Patch Exe". Select a decrypted FNEX exe, and it will patch the changes needed for the extra entries to work. I highly recommend backing up your ez2 data/exe before you do anything.

There are some other limitations/extra steps required to make this all work smoothly:

If you add entries to one game mode, you should at least add dummy entries to other game modes, they can be left blank as they just act as padding. This ensures all the song.bin files are the same size and will stop the game from crashing when loading the unmodded modes. if you cant be bothered a work around is loading the modded game mode first which pads the memory, then exiting to the start screen, and then loading the game mode you intend to play. CV2 and course modes are the only exclusions and so far have continued to function fine no matter how much I messed around with the other game modes.

The game appears to be unchanged unless you add the new entries to a category and also update the stage.ini file. Please remember to do this. I have provided the tools to decrypt and re-encrypt the .ini files for FNEX.

Only works on a decrypted EXE. However I could probably add something to my 2EZconfig tool to make the exe patch not required.

You cannot leave low difficulties blank (for example, if the song only has one difficulty, you must fill in NM, if it has 2, NM and HD and etc. You cannot skip a difficulty) leaving a low difficulty blank and populating the rest causes the game to crash when loading the mode.

Max chart level is 20, entering 21 will show the chart difficulty as a skull and bones.

Categories are still limited to the original song count of them game, I couldn't work out the fix for this but to be honest I didn't spend much time on it. So don't add any new songs to the "ALL" category.

Don't use the delete buttons lol, i forgot to finish these and i think the category one just deletes a song from the bottom

Earlier I mentioned something about unused songs. Well it turns out there were a few unused revivals from NT for songs that managed to be shipped with the game that I found, and some extras that were included with cv2 exclusive revivals. These are added fairly easily just by adding entries for them with my tool, updating the stage.ini and patching the exe. Available for all modes (double check the files though) and refer to namu wiki entries to get bpm and chart difficulties:

Orange (11orange)

Wake Me Up! (11wake)

Space Mia (11spacemia)

Akasha (7akasha)

Dragon Hunter (7happy)

For the TOP (7top)

Step in the Dayz (7step)

NPTW (7rossini)

There's also an unused 5KStandard SHD Stargazer remix chart that can be easily added just by editing the streetmix song.bin stargazer entry and adding a value for the SHD difficulty. no exe patch or updating of the stage.ini file required There's probably more that I'm yet to find.

There are references to other revivals from EV, but sadly none of the chart data was included with fnex.
This also includes tools for decrypting/re-encrypting ezi, ez and ini files for fnex, nt and ev. This was made by modding the old decrypt/encrypt tool with the relevant rainbow tables.
If you happen to make anything cool with the assistance of this tool please release it here!