Goomba is a Gameboy emulator for the Gameboy Advance. Beyond the advantage of being able to store many games on one cart, Goomba also includes save states and customizable borders. At least, my fork does. Also available are many palettes, along with the ability to make your own.
The process to actually included custom borders can be quite complex, so I've created a tutorial which should help guide you through the process. Currently this project is somewhat ongoing. The most probable future release would include a cheat finder of some nature. But, it will probably be a while before any attempts to add this are made.
Adding a palette is relatively easy. Create a text file with four lines, each with the rgb values of background, window, object 1, and object 2 layers, use txt2pal.py to create a palette file, and copy the palette to the end of goomba.gba.
Example palette Metroid.txt file:
Converting Metroid.txt to Metroid.pal
How to append Metroid.pal to goomba.gba as goomba_new.gba:
To actually add a custom border requires a program called append. This name derived from the original design: creating a border file through the tool and appending it to the goomba.mba file. However, future changes have also made it possible to prepend to the .gb file itself in some cases, so the name is no longer very accurate. A java version of Append is included in the binary distribution above.
As mentioned above, look at the tutorial for guidance on creating and adding borders.
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