diff --git a/ch32v003fun/ch32v003fun.mk b/ch32v003fun/ch32v003fun.mk
index fc382a34f953b94a0fc1f4b417c092459bb8b2be..a29c248a3af52f50b87e299658c1689d44748bec 100644
--- a/ch32v003fun/ch32v003fun.mk
+++ b/ch32v003fun/ch32v003fun.mk
@@ -28,7 +28,7 @@ ifeq ($(TARGET_MCU),CH32V003)
 		-I$(CH32V003FUN) \
 		-nostdlib \
 		-DCH32V003=1 \
-		-I. -Wall $(EXTRA_CFLAGS)
+		-I. -Wall
 
 	GENERATED_LD_FILE?=$(CH32V003FUN)/generated_ch32v003.ld
 	TARGET_MCU_LD:=0
@@ -46,6 +46,8 @@ else
 	endif
 endif
 
+CFLAGS+= $(EXTRA_CFLAGS)
+
 LDFLAGS+=-T $(LINKER_SCRIPT) -Wl,--gc-sections
 
 ifeq ($(TARGET_MCU), CH32V003)