diff --git a/system/vl.c b/system/vl.c
index ff76eb0d07..8c803228f4 100644
--- a/system/vl.c
+++ b/system/vl.c
@@ -194,7 +194,7 @@ static int default_sdcard = 1;
 static int default_vga = 1;
 static int default_net = 1;
 
-static struct {
+static const struct {
     const char *driver;
     int *flag;
 } default_list[] = {