Hi there. You're probably looking for GBAUtil. Unfortunately, I lost all my development and release files of GBAUtil in a hard disk drive crash a long time ago. Then, my web host removed all my files without warning me first, thus wiping out any chance of resurrecting GBAUtil.

Fortunately, most of the GBAUtil code was incorporated into other programs. Check out Flash Advance Tools for these. As far as I know, both F.A.T (my preference, since the author asked nicely for an exception to my license) and LittleWriter (*ahem*) both incorporate said code, and since LittleWriter is maintained, it probably works with all the latest games, etc.

Thanks for your interest in GBAUtil!