diff --git a/src/Makefile.defs b/src/Makefile.defs
index eb6993a30a4..c7d970e9c6d 100644
--- a/src/Makefile.defs
+++ b/src/Makefile.defs
@@ -377,7 +377,7 @@ endif
 
 # retarget amd64 to x86_64
 ifeq ($(ARCH), amd64)
-	ARCH=x86_64
+	override ARCH=x86_64
 endif
 
 $(info target architecture <$(ARCH)>, host architecture <$(HOST_ARCH)>)