http://www.chrisantonellis.com/gameboy/gbtdg/

with the help of this little website I was able to create a little Game Boy ROM, that displays the hackaday jolly wrencher. You can find the code and rom in the file sections. I tried to upload the files and write it to the cartridge, but had no success so far. Not sure what's going on, but I'm too tired to try to find out.

You only need to add the following code to the generated C file, depending on that your file was called something like HaDlogo.bmp - otherwise you have to rename stuff.

#include <gb/gb.h>
#include <stdio.h>

void main()
{
  set_bkg_data(0,255,HaDlogo_tile_data);
  VBK_REG = 1;
  set_bkg_tiles(0,0,20,18,HaDlogo_map_data);
  SHOW_BKG;
  DISPLAY_ON;
}