Made this quick.A nice cleaned up GBA loader. Just replace gbaframe.bmp with this one, and it should work.Enjoy .= Unzip .rar with winrar - rarlabs.com
I don't have a wii u anymore to test it myself, but if homebrews are not visible on the wii u menu I think you can press L + R + minus to open the plugin menu, there should be an option called "homebrews on wii u menu" or something similar