Index: tboard.c
===================================================================
--- tboard.c	(revision 22505)
+++ tboard.c	(revision 22506)
@@ -466,6 +466,8 @@
 		}
 		else if ((argc == 2) && (strcmp(argv[0], "end") == 0) && (strcmp(argv[1], "board") == 0))
 			break;
+		else
+			errexit("Invalid command in board\n");
 	}
 
 	if (stackup != NULL) {