For those attempting to use DeSmuME to play Pokemon HeartGold/SoulSilver without the capacity to read and write the sourcecode, you may want to be informed that the DeSmuME development team is not modifying their code to support these releases. Source: http://wiki.desmume.org/index.php?title=Faq#Why_can.27t_I_play_Pokemon_HeartGold_.2F_SoulSilver_.3F_Why_aren.27t_they_supported_.3F