diff --git a/drivers/net/wan/hdlc_cisco.c b/drivers/net/wan/hdlc_cisco.c
index a030f5aa6b95..cc33441af469 100644
--- a/drivers/net/wan/hdlc_cisco.c
+++ b/drivers/net/wan/hdlc_cisco.c
@@ -370,6 +370,7 @@ static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr)
 		memcpy(&state(hdlc)->settings, &new_settings, size);
 		spin_lock_init(&state(hdlc)->lock);
 		dev->header_ops = &cisco_header_ops;
+		dev->hard_header_len = sizeof(struct hdlc_header);
 		dev->type = ARPHRD_CISCO;
 		call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
 		netif_dormant_on(dev);