diff --git a/scripts/Makefile.modinst b/scripts/Makefile.modinst
index 07650ee..6f4c3f5 100644
--- a/scripts/Makefile.modinst
+++ b/scripts/Makefile.modinst
@@ -29,7 +29,7 @@
 INSTALL_MOD_DIR ?= extra
 ext-mod-dir = $(INSTALL_MOD_DIR)$(subst $(patsubst %/,%,$(KBUILD_EXTMOD)),,$(@D))
 
-modinst_dir = $(if $(KBUILD_EXTMOD),$(ext-mod-dir),kernel/$(@D))
+modinst_dir ?= $(if $(KBUILD_EXTMOD),$(ext-mod-dir),kernel/$(@D))
 
 $(modules):
 	$(call cmd,modules_install,$(MODLIB)/$(modinst_dir))