diff --git a/boot/grub2/grub2.mk b/boot/grub2/grub2.mk
index af16ee91e1..52e9199ae9 100644
--- a/boot/grub2/grub2.mk
+++ b/boot/grub2/grub2.mk
@@ -118,9 +118,11 @@ HOST_GRUB2_CONF_ENV = \
 GRUB2_CONF_ENV = \
 	CPP="$(TARGET_CC) -E" \
 	TARGET_CC="$(TARGET_CC)" \
-	TARGET_CFLAGS="$(TARGET_CFLAGS)" \
-	TARGET_CPPFLAGS="$(TARGET_CPPFLAGS) -fno-stack-protector" \
-	TARGET_LDFLAGS="$(TARGET_LDFLAGS)" \
+	CFLAGS="$(TARGET_CFLAGS) -Os" \
+	TARGET_CFLAGS="$(TARGET_CFLAGS) -Os" \
+	CPPFLAGS="$(TARGET_CPPFLAGS) -Os -fno-stack-protector" \
+	TARGET_CPPFLAGS="$(TARGET_CPPFLAGS) -Os -fno-stack-protector" \
+	TARGET_LDFLAGS="$(TARGET_LDFLAGS) -Os" \
 	TARGET_NM="$(TARGET_NM)" \
 	TARGET_OBJCOPY="$(TARGET_OBJCOPY)" \
 	TARGET_STRIP="$(TARGET_CROSS)strip"