diff --git a/rules.d/core-rules.sh b/rules.d/core-rules.sh
index c563594d..d29300e6 100644
--- a/rules.d/core-rules.sh
+++ b/rules.d/core-rules.sh
@@ -589,7 +589,7 @@ libretro_mame2003_git_url="https://github.com/libretro/mame2003-libretro.git"
 libretro_mame2003_makefile="Makefile"
 
 include_core_mame2003_plus() {
-	register_module core "mame2003-plus" -theos_ios -ngc -psp1 -wii
+	register_module core "mame2003_plus" -theos_ios -ngc -psp1 -wii
 }
 libretro_mame2003_plus_name="MAME 2003 Plus (0.78)"
 libretro_mame2003_plus_git_url="https://github.com/libretro/mame2003-plus-libretro.git"