i think the default_mp.elf is for cod games and it is in the same folder as ur eboot. but for other games that dont have default_mp.elf u just use the eboot and make debug eboot or elf
Default_mp.elf is for the multiplayer boot on games, most multiplayer games will have them, and if your looking to create a debug eboot then just use the elf and use make_fself.