Rockman 4 minus infinity rgb compatible reproduction cartridge

Satoshimatrix kept telling me how amazing the rockman 4 minus infinity romhack is.  I read online that it's possible to make this game run on an actual cartridge.  This particular game is mmc5, I conveniently had a spare game with a mmc5 pcb sitting in my closet not being used for anything.  This conversion isn't very easy.  You need to desolder the chr rom and the prg rom as well.  You need to solder a 8k ram chip into the chr rom spot and rewire it a bit.  You need to solder the maskrom into the prg rom spot and again do rewiring.  I was handed a wiring guide and I fixed a bunch of stuff on the guide:



This guide before I changed stuff had you cutting traces all over the pcb which you don't need to do.  The ram chip part number was for a ram chip with the wrong pinout so I removed that number.  You can also use a m27c801 chip for the maskrom.  The pcb I used was a different pcb.  This guide is stupidly only made for one pcb type but there's more than one type of mmc5 pcb you can use.

My reproduction worked first try without cutting a single trace on the pcb.  Here's how my cart looks right now:



The ram chip and maskrom I added are socketed for now.  I wired up the maskrom socket so it's eprom pinout this way for future updates I can just burn a new eprom, drop it in, and play.

Of course since this is the most awesome romhack ever made the hacker used every trick the nes can do, including color emphasis which the rgb ppu chip doesn't do.  After having the author of this hack tell me he won't make a version without color emphasis, myself + spikeman set out to romhack it out ourselves.  We succeeded, any parts that used to use color emphasis we changed into using grayscale.





This romhack truly is amazing.  It adds the ability to save your game with a battery backed ram chip so no more passwords.  This game is so converted it feels like a completely new rockman game, and it's made extremely well.

Wow. That looks like one impressive ROMhack. Must be nice to play on real hardware
Since your/spikeman's hack, everything using color emphasis is just turned to greyscale? Or does it just use greyscale as the color emphasis modifier? It looks as though the former is true, judging by your picture.

Grambo wrote:

Wow. That looks like one impressive ROMhack. Must be nice to play on real hardware
Since your/spikeman's hack, everything using color emphasis is just turned to greyscale? Or does it just use greyscale as the color emphasis modifier? It looks as though the former is true, judging by your picture.

Yeah we reprogrammed the writes to the ppu mask from setting color emphasis to setting grayscale mode instead.  The way the effect works is the color emphasis part of the screen is the part where sprites aren't drawn so it needs to look different from the regular part of the screen.  The other stage in the game with color emphasis has a water level that rises and falls and again color emphasis was used to make the water area darker.  You need to be able to tell where the water level is for the gameplay so instead of just turning color emphasis off I changed it to grayscale so you can see the difference between the regular background.

Color emphasis in the nes just makes colors darker. Here's all the drawing tricks you can do by writing to the ppu mask:

76543210
||||||||
|||||||+- Grayscale (0: normal color; 1: produce a monochrome display)
||||||+-- 1: Show background in leftmost 8 pixels of screen; 0: Hide
|||||+--- 1: Show sprites in leftmost 8 pixels of screen; 0: Hide
||||+---- 1: Show background
|||+----- 1: Show sprites
||+------ Intensify reds (and darken other colors)
|+------- Intensify greens (and darken other colors)
+-------- Intensify blues (and darken other colors)

Bits 5, 6 and 7 are the emphasis bits which the rgb ppu chip doesn't do right.