diff --git a/sys/dev/usb/net/if_urndis.c b/sys/dev/usb/net/if_urndis.c
--- a/sys/dev/usb/net/if_urndis.c
+++ b/sys/dev/usb/net/if_urndis.c
@@ -214,15 +214,15 @@
 static int
 urndis_attach(device_t dev)
 {
-	static struct {
-		union {
+	union {
+		struct {
 			struct rndis_query_req query;
+			uint8_t addr[ETHER_ADDR_LEN];
+		} eaddr;
+		struct {
 			struct rndis_set_req set;
-		} hdr;
-		union {
-			uint8_t eaddr[ETHER_ADDR_LEN];
 			uint32_t filter;
-		} ibuf;
+		} filter;
 	} msg;
 	struct urndis_softc *sc = device_get_softc(dev);
 	struct usb_ether *ue = &sc->sc_ue;
@@ -278,10 +278,10 @@
 	}
 
 	/* Determine MAC address */
-	memset(msg.ibuf.eaddr, 0, sizeof(msg.ibuf.eaddr));
+	memset(msg.eaddr.addr, 0, sizeof(msg.eaddr.addr));
 	URNDIS_LOCK(sc);
 	error = urndis_ctrl_query(sc, OID_802_3_PERMANENT_ADDRESS,
-	    &msg.hdr.query, sizeof(msg.hdr.query) + sizeof(msg.ibuf.eaddr),
+	    (struct rndis_query_req *)&msg.eaddr, sizeof(msg.eaddr),
 	    &buf, &bufsz);
 	URNDIS_UNLOCK(sc);
 	if (error != (int)RNDIS_STATUS_SUCCESS) {
@@ -297,10 +297,10 @@
 	/* Initialize packet filter */
 	sc->sc_filter = NDIS_PACKET_TYPE_BROADCAST |
 	    NDIS_PACKET_TYPE_ALL_MULTICAST;
-	msg.ibuf.filter = htole32(sc->sc_filter);
+	msg.filter.filter = htole32(sc->sc_filter);
 	URNDIS_LOCK(sc);
 	error = urndis_ctrl_set(sc, OID_GEN_CURRENT_PACKET_FILTER,
-	    &msg.hdr.set, sizeof(msg.hdr.set) + sizeof(msg.ibuf.filter));
+	    (struct rndis_set_req *)&msg.filter, sizeof(msg.filter));
 	URNDIS_UNLOCK(sc);
 	if (error != (int)RNDIS_STATUS_SUCCESS) {
 		device_printf(dev, "Unable to set data filters\n");
@@ -641,7 +641,7 @@
 		msg_filter.filter = htole32(sc->sc_filter);
 
 		rval = urndis_ctrl_set(sc, OID_GEN_CURRENT_PACKET_FILTER,
-		    &msg_filter.hdr, sizeof(msg_filter));
+		    (struct rndis_set_req *)&msg_filter, sizeof(msg_filter));
 
 		if (rval != RNDIS_STATUS_SUCCESS) {
 			DPRINTF("unable to reset data filters\n");