diff --git a/xen/arch/arm/efi/Makefile b/xen/arch/arm/efi/Makefile
index dffe72e589..bd954a3b2d 100644
--- a/xen/arch/arm/efi/Makefile
+++ b/xen/arch/arm/efi/Makefile
@@ -9,4 +9,7 @@ else
 # will not be cleaned in "make clean".
 EFIOBJ-y += stub.o
 obj-y += stub.o
+
+$(obj)/stub.o: CFLAGS-y += -fno-short-wchar
+
 endif