diff --git a/board/prodrive/p3p440/p3p440.c b/board/prodrive/p3p440/p3p440.c
index 020f66d..1bb9686 100644
--- a/board/prodrive/p3p440/p3p440.c
+++ b/board/prodrive/p3p440/p3p440.c
@@ -122,12 +122,13 @@
 
 int checkboard(void)
 {
-	char *s = getenv("serial#");
+	char buf[64];
+	int i = getenv_f("serial#", buf, sizeof(buf));
 
 	printf("Board: P3P440");
-	if (s != NULL) {
+	if (i > 0) {
 		puts(", serial# ");
-		puts(s);
+		puts(buf);
 	}
 
 	if (is_monarch()) {