diff --git a/rules.d/core-rules.sh b/rules.d/core-rules.sh
index d167d8a8..12f6d54d 100644
--- a/rules.d/core-rules.sh
+++ b/rules.d/core-rules.sh
@@ -223,10 +223,10 @@ libretro_mame078_name="MAME 2003 (0.78)"
 libretro_mame078_git_url="https://github.com/libretro/mame2003-libretro.git"
 libretro_mame078_makefile="Makefile"
 
-register_module core "mame139" none
+register_module core "mame139"
 libretro_mame139_name="MAME 2010 (0.139)"
 libretro_mame139_git_url="https://github.com/libretro/mame2010-libretro.git"
-libretro_mame139_build_rule=none # NEED A BUILD RULE
+libretro_mame159_makefile="Makefile.libretro"
 
 register_module core "mame159" -theos_ios -ngc -psp1 -wii
 libretro_mame159_name="MAME 2014 (0.159)"