Nintendo Helifire Free Play Mod

[SNESNESCUBE64 | 629]

So a few days ago I obtained a Nintendo Helifire cocktail table. The problem is that I like having all my games on free play if I can help it. Mainly because I don't want to keep a bunch of quarters around. Helifire unfortunately does not have a free play mode, so I had to mod the ROMs in order to support it.

It was pretty interesting altogether. I used the MAME debugger to go through the disassembly in order to figure out what routines did what and where coin stuff and start stuff happened. The approach I took was to remap the coin switch to the start buttons, rewritting the routines to determine which button was press to add an appropriate amount of credits. From there I set up the game to autostart after coin insert. I tried just jumping to the start of the game but that did not work, it does some goofy stuff when it goes through the coin routine.

After rewriting the routines to do act as a free play, it was just rewriting the "insert coin" and "credits" text. This is what I ended up with.

I only ended up needing to change two of the ten ROM chips to support it. One with actual code and the other with the free play text. This was a bit more complicated than the free play mod I had to write for Head On N. I can't wait to try this on real hardware, I just have to fix the game board.

Edited October 17, 2023 by SNESNESCUBE64

[SNESNESCUBE64 | 629]

Finally got the board working enough to test my mod. Super happy that it is working as it should.

Edited October 27, 2023 by SNESNESCUBE64