Index: sys/nfs/bootp_subr.c
===================================================================
--- sys/nfs/bootp_subr.c	(revision 268986)
+++ sys/nfs/bootp_subr.c	(working copy)
@@ -1551,8 +1551,11 @@ bootpc_init(void)
 	struct nfsv3_diskless *nd;
 	struct thread *td;
 	int timeout;
-	int delay;
+	int delay, disable;
 
+	if (TUNABLE_INT_FETCH("vfs.nfs.bootp_disable", &disable) && disable)
+		return;
+
 	timeout = BOOTP_IFACE_WAIT_TIMEOUT * hz;
 	delay = hz / 10;