diff --git a/build/systemMenu_RED/HWInfoWriter/ARM9/Makefile b/build/systemMenu_RED/HWInfoWriter/ARM9/Makefile
index d40da71c..594da005 100644
--- a/build/systemMenu_RED/HWInfoWriter/ARM9/Makefile
+++ b/build/systemMenu_RED/HWInfoWriter/ARM9/Makefile
@@ -22,6 +22,7 @@ SUBDIRS					=	\
 
 USE_PRODUCT_KEY		=	TRUE
 
+KEYS_DIR				=	$(shell $(CYGPATH) -m $(TWL_KEYSDIR))
 TARGET_FIRM				=	SYSTEMMENU
 TARGET_PLATFORM			=	TWL
 TWL_ARCHGEN				=	LIMITED
@@ -47,7 +48,7 @@ MAKEROM_FLAGS			+=	-DTITLEID_LO='$(TITLEID_LO)' \
 MAKETAD_FLAGS			+=	-s
 
 ifdef USE_PRODUCT_KEY
-MAKEROM_FLAGS			+=	-DPRIVKEY_PATH='$(TWL_KEYSDIR)/rsa'
+MAKEROM_FLAGS			+=	-DPRIVKEY_PATH='$(KEYS_DIR)/rsa'
 MACRO_FLAGS				+=	-DUSE_PRODUCT_KEY
 else
 MAKEROM_FLAGS			+=	-DPRIVKEY_PATH='../../../../keys/dummy/rsa'