diff --git a/src/bin/fwcontrol/fwcontrol.c b/src/bin/fwcontrol/fwcontrol.c
index eac83826b3..33fd80de9f 100644
--- a/src/bin/fwcontrol/fwcontrol.c
+++ b/src/bin/fwcontrol/fwcontrol.c
@@ -139,7 +139,7 @@ str2node(int fd, const char *nodestr)
 	char *endptr;
 	int i, node;
 
-	if (nodestr == '\0')
+	if (nodestr == NULL || *nodestr == '\0')
 		return (-1);
 
 	/*