How to start hacking your own ROMs

by Kasady


Okay, before you should jump into ROM hacking, you need to know what to do and use. I’ll share what I’ve learned through doing my hacks, so you’ll know what to need and expect.

Tools you will need-

         NESticle
         Pasowing
         a tool to convert between .nes and .prm format
        the ROM

Stuff you might want-

       graph paper
       pencil
       a toy that looks like the object(explained later on)
       a Hex editor
       a compression utility(Winzip or PKUnzip)

     Okay, now that you have the ROM you want to hack, load it into the emulator. In NESticle, open the pattern tables and edit each sprite as you would draw something in a paint program. In paso, though, you need to open the debugger, which I haven’t used yet. Anyway, you can only use the colors the sprite uses.
Since you can only edit in 8x8 squares, it might be useful to have a plan of what you want to do. You can only use the same number of squares the sprite uses, too. You can color edit to make a sprite look smaller, but the sprite is still the same size as before. You can’t make sprites bigger, either.  It helps to pause the ROM with Alt-P. This is easier than simply pausing the game, especially when pausing with ‘start’ brings up a new screen. After editing the sprite, you need to save your work. In NESticle, click on ‘Write VROM’. 
Paso is easier, if you know what button to press. 
       Earlier I mentioned a conversion utility. Since NESticle can only hack ROMs with VROM, you need to use Pasowing to hacks games without VROM.  Graph paper can be very helpful, since you can draw the 8x8 squares out to look at without having the ROM loaded. It’s also useful if you are taking graphics from one game and putting them on another without doing a cut-and-paste operation that could screw up the ROM.
Markers or colored pencils can be used to color-code the squares, or you could simply label each area with a letter( i.e. R-red,  w-white, ect.). An action figure or a small statue can be helpful, since that gives you a 3-dimensional model to look off of. A figure with many joints is recommended, since it can be put into a position you might want. Don’t worry about detail in a figure, since these are 8-bit games. Anyway, detailed figures can cost a lot more than jointed figures.
    Next, there’s a hex editor. This is useful for color alterations and text editing. To edit colors without screwing up the palette the emulator uses, use this simple process. In NESticle, open up the game palette. There’s a value next to each color. Simply click on the color to see this value. That value is hex code for that color. Write down the code for each color that the sprite uses, then write down the value you want to use. This value  MUST BE  the exact length as the original code. If you add or subtract even ONE digit when editing, you’ll ruin the ROM. When you have the original value and the new value, open the Hex Editor and then open the ROM. You’ll see letters and numbers that will look odd. That’s the Hex code.( I use Hex Workshop. I recommend using this for beginners.), then do a search for the hex code you want to replace. Then replace the original value with the new value. Then save. Load the ROM in the emulator. You should see the old color replaced with the new colors. Here’s an example:  In Super Mario Bros. Mario is red, brown, pink, and clear. When I did Carnage, I needed red, black, white, and clear. Since I needed clear and red anyway, I didn’t need to change them. When replacing, though, I had to type in the value for red and clear to keep them.
     Editing text is similar. Open the pattern tables, and determine the hex values for the letters(  open the square like you would when editing a sprite) .The hex value is the numbers in the corner. For now,  concentrate on replacing a word with another word with the same number of letters.  This is simpler than trying to change the length of the word, since it can be nearly impossible to find the hex value of the blank spaces. Then open the hex editor, open the ROM, and do what you did when color editing. Editing words this way will prevent letter errors that some hacks have. Example- In Carnage, I changed ‘Mario’ to ‘Clete’
since ‘Carnage’ would have been impossible.
             Hopefully, the steps above should help you get started. I outlined the basic tools and steps to help you along. These are the secrets I use, and they work for me. But, you should find something that works for you. Since hacking can take a long time, especially for a good job, you will need patience. Good luck!