diff --git a/Make.defaults b/Make.defaults
index e11ab5a..ac2a25b 100644
--- a/Make.defaults
+++ b/Make.defaults
@@ -89,7 +89,7 @@ ifeq ($(ARCH),aarch64)
 	ARCH_SUFFIX_UPPER	?= AA64
 	FORMAT			:= -O binary
 	SUBSYSTEM		:= 0xa
-	ARCH_LDFLAGS		+= --defsym=EFI_SUBSYSTEM=$(SUBSYSTEM)
+	override ARCH_LDFLAGS		+= --defsym=EFI_SUBSYSTEM=$(SUBSYSTEM)
 endif
 ifeq ($(ARCH),arm)
 	CFLAGS += -DMDE_CPU_ARM -DPAGE_SIZE=4096 -mstrict-align
@@ -98,7 +98,7 @@ ifeq ($(ARCH),arm)
 	ARCH_SUFFIX_UPPER	?= ARM
 	FORMAT			:= -O binary
 	SUBSYSTEM		:= 0xa
-	ARCH_LDFLAGS		+= --defsym=EFI_SUBSYSTEM=$(SUBSYSTEM)
+	override ARCH_LDFLAGS		+= --defsym=EFI_SUBSYSTEM=$(SUBSYSTEM)
 endif
 
 FORMAT		?= --target efi-app-$(ARCH)