diff --git a/core/net/rime/runicast.c b/core/net/rime/runicast.c
index e03a881d1..946fef0e7 100644
--- a/core/net/rime/runicast.c
+++ b/core/net/rime/runicast.c
@@ -101,11 +101,12 @@ sent_by_stunicast(struct stunicast_conn *stunicast, int status, int num_tx)
       PRINTF("%d.%d: runicast: packet %d timed out\n",
              rimeaddr_node_addr.u8[0],rimeaddr_node_addr.u8[1],
              c->sndnxt);
+      c->sndnxt = (c->sndnxt + 1) % (1 << RUNICAST_PACKET_ID_BITS);
     } else {
-      int shift;
+//      int shift;
       
-      shift = c->rxmit > 4? 4: c->rxmit;
-      stunicast_set_timer(&c->c, (REXMIT_TIME) << shift);
+//      shift = c->rxmit > 4? 4: c->rxmit;
+//      stunicast_set_timer(&c->c, (REXMIT_TIME) << shift);
     }
   }
 }
diff --git a/core/net/rime/stunicast.c b/core/net/rime/stunicast.c
index 3309bfd64..554e81da0 100644
--- a/core/net/rime/stunicast.c
+++ b/core/net/rime/stunicast.c
@@ -113,9 +113,11 @@ send(void *ptr)
   PRINTF("%d.%d: stunicast: resend to %d.%d\n",
 	 rimeaddr_node_addr.u8[0],rimeaddr_node_addr.u8[1],
 	 c->receiver.u8[0], c->receiver.u8[1]);
-  queuebuf_to_packetbuf(c->buf);
-  unicast_send(&c->c, &c->receiver);
-  stunicast_set_timer(c, CLOCK_SECOND);
+	 if(c->buf) {
+  	queuebuf_to_packetbuf(c->buf);
+  	unicast_send(&c->c, &c->receiver);
+  	stunicast_set_timer(c, CLOCK_SECOND);
+  }
   /*  if(c->u->sent != NULL) {
     c->u->sent(c);
     }*/