Making a Patch

Contributors: Bivurnum

When your ROM hack is ready to distribute to others, you'll need to provide them with a patch.

Caution

It is illegal to distribute full ROMs to other people. This is technically distributing Nintendo's and The Pokémon Company's property without their permission. It is a prosecutable act. Don't do it!

Distributing a patch to other people technically skirts around committing any illegal acts because you are only distributing your own changes and not Nintendo's original code. That is the theory, anyway.

There are a few different ways to make a patch, but I will be showing you the one that I use.
Follow the link to this online patcher, Rom Patcher JS:

Click the toggle in the upper right to switch it to Creator Mode:

Where it says "Original ROM", you'll have to provide the base ROM that you want people to be able to apply your patch to. This will be an unedited ROM of either Emerald or FireRed (depending on which one you decided to hack). There are different versions of these games out there, so you should always specify which base ROM version you used to make your patch.
Most modern ROM hackers choose to use these specific versions because they are distinctly named and easy to find:

• 1986 - Pokemon Emerald (U)(TrashMan)
• 1636 - Pokemon Fire Red (U)(Squirrels)

Note

I cannot tell you where to find or download base ROMs, similar to the legal disclaimer above. However, these shouldn't be hard for you to find if you look. Search engines are a wonderous thing.

Where it says "Modified ROM", you will provide the ROM that you compiled from your decomp. This will be located in your project folder and will be a .gba file. For example, if you are working with pokeemerald, it will be in the "pokeemerald" folder and it will be named "pokeemerald.gba".

The "Patch Type" is completely up to you. They are just different formats of patches. If your patch doesn't work for someone, try making a new patch using a different format.

Once you have everything filled in, just click the "Create Patch" button and it will prompt you to name it and designate where you'd like to download it on your device:

Congratulations! You can provide a copy of your patch to whoever you want and they can use it to patch their own copy of your ROM hack! If you wanted to provide a download link for anyone to download it, you could host your patch on Mediafire and provide a link to that.

Next section: Applying a Patch