diff --git a/lib/smbios.c b/lib/smbios.c
index 7b74971..1179044 100644
--- a/lib/smbios.c
+++ b/lib/smbios.c
@@ -31,6 +31,8 @@
 {
 	int i = 1;
 	char *p = start;
+	if (!*str)
+		str = "Unknown";
 
 	for (;;) {
 		if (!*p) {