This is the second of the series of Instructables that I will be making on Pokémon ROM hacking. You can find the first one here. This Instructable shows you how to change the Pokémon logo and the version (Fire Red Version, Emerald Version, etc...). Unlike the first Pokémon Hacking Instructable I made, this one applies to all GBA versions of Pokémon.
Step 1: Get the Palette
To grab the palette of the title screen, I use Visual Boy Advance, which is also the program I use for GBA ROM emulation. If you don't already have it, you can get it from here. Once you reach the title screen in-game, in VBA, in the header, click on "Tools", the on "Palette Viewer". You should get a windows similar to the one above.
Depending on which program you are going to use, there are two options on what you are about to do. If you use PhotoShop (highly recommendable), just click on "Save BG..." and in the "Save as type" box, select "*.ACT". If you use Gimp, just keep this windows open. Why do I recommend PhotoShop over Gimp for this task? Because in PhotoShop you can just import the file you just saved, and in Gimp you will have to copy out every single one of those 256 little colored boxes by hand. So, if you can't or don't want to pay for PhotoShop, there's either the free 30-day trial, or there's Gimp.
You can but PhotoShop here.
You can register for the free trial here.
You can download Gimp here.
Step 2: Original Pokémon Logo and Version
Before anything, you need to get the original image with the Pokémon logo and version. To do so, you will need unLZ-GBA. If you followed my previous Instructable, you should already have it, if not, you can get it from here. Once opened, load your ROM using the "Open File" button. Type in 2009 (for Fire Red. See below for all games) next to the "Go To" button, then press it. In the top right corner, select "256 Color Mode", then tick the "Use Black/White" option. Click on the "+" button once or twice, and a black and white picture of the Pokémon logo and the version should appear. If you see a different image, or don't see any image at all, click on the "Next" and "Previous" buttons a few times to look for the image. If you modded the ROM before, it may have changed location by a few numbers.
Fire Red: 2009
Leaf Green: 2010
Ruby: 1637 and 1638
Emerald: 2611 and 2612
Sapphire: 1635 and 1636
Step 3: Gimp Method
In Gimp, open up your image, then click on "Windows" in the header of the main window. In the dropdown menu that appears, select "Dockable Dialogs", then "Colormap". A window will pop up with the different shades of grey in the image. Edit each one to match the colors in the VBA palette. Once that's done, you can edit your image. Keep in mind that approximately the first two thirds are for the Pokémon logo, and the last third for the version. You can delete the leftover piece of the version that's under the Pokémon logo in the image. It isn't needed. When you finished editing your image, change the palette back to the shades of grey it had and save it.
Step 4: PhotoShop Method
In PhotoShop, click on "Image", then select "Mode", and click on "Color Table". Click on the "Load..." button, load the palette you saved earlier, and click OK. Now you can edit your image. Once you're done, open the palette again, and click the button right above the it. In the dropdown menu select "Greyscale". Click OK and save the image.
Step 5: Insert Picture
Open unLZ-GBA and navigate to 2009 (or whichever number corresponds to the location of your picture) click on "Import", then on "Write To ROM". If you get a "too big" error, follow these steps.
Step 6: Final Result
Load your ROM to check that everything is correct in your emulator, make changes if needed, and contemplate your work.