diff --git a/tmk_core/rules.mk b/tmk_core/rules.mk
index 543d3da8a..8d843cc98 100644
--- a/tmk_core/rules.mk
+++ b/tmk_core/rules.mk
@@ -260,7 +260,7 @@ LST = $(patsubst %.c,$(OBJDIR)/%.lst,$(patsubst %.cpp,$(OBJDIR)/%.lst,$(patsubst
 
 # Compiler flags to generate dependency files.
 #GENDEPFLAGS = -MMD -MP -MF .dep/$(@F).d
-GENDEPFLAGS = -MMD -MP -MF $(BUILD_DIR)/.dep/$(subst /,_,$@).d
+GENDEPFLAGS = -MMD -MP -MF $(BUILD_DIR)/.dep/$(subst /,_,$(subst $(BUILD_DIR)/,,$@)).d
 
 
 # Combine all necessary flags and optional flags.