diff --git a/board/actux3/actux3.c b/board/actux3/actux3.c
index 63bf365..bace254 100644
--- a/board/actux3/actux3.c
+++ b/board/actux3/actux3.c
@@ -111,14 +111,15 @@
  */
 int checkboard (void)
 {
-	char *s = getenv ("serial#");
+	char buf[64];
+	int i = getenv_f("serial#", buf, sizeof(buf));
 
 	puts ("Board: AcTux-3 rev.");
 	putc (ACTUX3_BOARDREL + 'A' - 1);
 
-	if (s != NULL) {
+	if (i > 0) {
 		puts (", serial# ");
-		puts (s);
+		puts (buf);
 	}
 	putc ('\n');