diff --git a/core/dev/slip.c b/core/dev/slip.c
index 6b8a24ceb..451b9ec6c 100644
--- a/core/dev/slip.c
+++ b/core/dev/slip.c
@@ -293,7 +293,7 @@ PROCESS_THREAD(slip_process, ev, data)
       tcpip_input();
 #endif
     } else {
-      uip_len = 0;
+      uip_clear_buf();
       SLIP_STATISTICS(slip_ip_drop++);
     }
 #else /* NETSTACK_CONF_WITH_IPV6 */
diff --git a/core/net/ip/tcpip.c b/core/net/ip/tcpip.c
index 1c75d1bc9..0505b3d47 100644
--- a/core/net/ip/tcpip.c
+++ b/core/net/ip/tcpip.c
@@ -529,10 +529,7 @@ void
 tcpip_input(void)
 {
   process_post_synch(&tcpip_process, PACKET_INPUT, NULL);
-  uip_len = 0;
-#if NETSTACK_CONF_WITH_IPV6
-  uip_ext_len = 0;
-#endif /*NETSTACK_CONF_WITH_IPV6*/
+  uip_clear_buf();
 }
 /*---------------------------------------------------------------------------*/
 #if NETSTACK_CONF_WITH_IPV6
@@ -548,13 +545,13 @@ tcpip_ipv6_output(void)
 
   if(uip_len > UIP_LINK_MTU) {
     UIP_LOG("tcpip_ipv6_output: Packet to big");
-    uip_len = 0;
+    uip_clear_buf();
     return;
   }
 
   if(uip_is_addr_unspecified(&UIP_IP_BUF->destipaddr)){
     UIP_LOG("tcpip_ipv6_output: Destination address unspecified");
-    uip_len = 0;
+    uip_clear_buf();
     return;
   }
 
@@ -591,7 +588,7 @@ tcpip_ipv6_output(void)
 #else
           PRINTF("tcpip_ipv6_output: Destination off-link but no route\n");
 #endif /* !UIP_FALLBACK_INTERFACE */
-          uip_len = 0;
+          uip_clear_buf();
           return;
         }
 
@@ -643,7 +640,7 @@ tcpip_ipv6_output(void)
 
 #if UIP_CONF_IPV6_RPL
     if(rpl_update_header_final(nexthop)) {
-      uip_len = 0;
+      uip_clear_buf();
       return;
     }
 #endif /* UIP_CONF_IPV6_RPL */
@@ -651,7 +648,7 @@ tcpip_ipv6_output(void)
     if(nbr == NULL) {
 #if UIP_ND6_SEND_NA
       if((nbr = uip_ds6_nbr_add(nexthop, NULL, 0, NBR_INCOMPLETE)) == NULL) {
-        uip_len = 0;
+        uip_clear_buf();
         return;
       } else {
 #if UIP_CONF_IPV6_QUEUE_PKT
@@ -689,7 +686,7 @@ tcpip_ipv6_output(void)
           uip_packetqueue_set_buflen(&nbr->packethandle, uip_len);
         }
 #endif /*UIP_CONF_IPV6_QUEUE_PKT*/
-        uip_len = 0;
+        uip_clear_buf();
         return;
       }
       /* Send in parallel if we are running NUD (nbc state is either STALE,
@@ -719,15 +716,14 @@ tcpip_ipv6_output(void)
       }
 #endif /*UIP_CONF_IPV6_QUEUE_PKT*/
 
-      uip_len = 0;
+      uip_clear_buf();
       return;
     }
     return;
   }
   /* Multicast IP destination address. */
   tcpip_output(NULL);
-  uip_len = 0;
-  uip_ext_len = 0;
+  uip_clear_buf();
 }
 #endif /* NETSTACK_CONF_WITH_IPV6 */
 /*---------------------------------------------------------------------------*/
diff --git a/core/net/ip/uip.h b/core/net/ip/uip.h
index cb12f52ab..a85929554 100644
--- a/core/net/ip/uip.h
+++ b/core/net/ip/uip.h
@@ -1326,6 +1326,22 @@ extern uint8_t uip_ext_len;
 extern uint16_t uip_urglen, uip_surglen;
 #endif /* UIP_URGDATA > 0 */
 
+/*
+ * Clear uIP buffer
+ *
+ * This function clears the uIP buffer by reseting the uip_len and
+ * uip_ext_len pointers.
+ */
+#if NETSTACK_CONF_WITH_IPV6
+#define uip_clear_buf() { \
+  uip_len = 0; \
+  uip_ext_len = 0; \
+}
+#else /*NETSTACK_CONF_WITH_IPV6*/
+#define uip_clear_buf() { \
+  uip_len = 0; \
+}
+#endif /*NETSTACK_CONF_WITH_IPV6*/
 
 /**
  * Representation of a uIP TCP connection.
diff --git a/core/net/ip64/ip64-slip-interface.c b/core/net/ip64/ip64-slip-interface.c
index 05fe704c7..8d46d78a8 100644
--- a/core/net/ip64/ip64-slip-interface.c
+++ b/core/net/ip64/ip64-slip-interface.c
@@ -59,7 +59,7 @@ input_callback(void)
   /*PRINTF("SIN: %u\n", uip_len);*/
   if(uip_buf[0] == '!') {
     PRINTF("Got configuration message of type %c\n", uip_buf[1]);
-    uip_len = 0;
+    uip_clear_buf();
 #if 0
     if(uip_buf[1] == 'P') {
       uip_ipaddr_t prefix;
@@ -87,7 +87,7 @@ input_callback(void)
       slip_send();
       
     }
-    uip_len = 0;
+    uip_clear_buf();
   } else {
     
     /* Save the last sender received over SLIP to avoid bouncing the
@@ -101,7 +101,7 @@ input_callback(void)
       uip_len = len;
       /*      PRINTF("send len %d\n", len); */
     } else {
-      uip_len = 0;
+      uip_clear_buf();
     }
   }
 }
diff --git a/core/net/ipv4/uip-fw.c b/core/net/ipv4/uip-fw.c
index c152231c0..530a0b7c0 100644
--- a/core/net/ipv4/uip-fw.c
+++ b/core/net/ipv4/uip-fw.c
@@ -229,7 +229,7 @@ time_exceeded(void)
   /* We don't send out ICMP errors for ICMP messages (unless they are pings). */
   if(ICMPBUF->proto == UIP_PROTO_ICMP &&
      ICMPBUF->type != ICMP_ECHO) {
-    uip_len = 0;
+    uip_clear_buf();
     return;
   }
   /* Copy fields from packet header into payload of this ICMP packet. */
diff --git a/core/net/ipv4/uip.c b/core/net/ipv4/uip.c
index 1c3c24aaf..48366a114 100644
--- a/core/net/ipv4/uip.c
+++ b/core/net/ipv4/uip.c
@@ -709,7 +709,7 @@ uip_process(uint8_t flag)
     }
 
     /* Reset the length variables. */
-    uip_len = 0;
+    uip_clear_buf();
     uip_slen = 0;
 
 #if UIP_TCP
@@ -1589,7 +1589,7 @@ uip_process(uint8_t flag)
       uip_add_rcv_nxt(1);
       uip_flags = UIP_CONNECTED | UIP_NEWDATA;
       uip_connr->len = 0;
-      uip_len = 0;
+      uip_clear_buf();
       uip_slen = 0;
       UIP_APPCALL();
       goto appsend;
@@ -1934,7 +1934,7 @@ uip_process(uint8_t flag)
   return;
 
  drop:
-  uip_len = 0;
+  uip_clear_buf();
   uip_flags = 0;
   return;
 }
diff --git a/core/net/ipv4/uip_arp.c b/core/net/ipv4/uip_arp.c
index 5abad8b40..10015295e 100644
--- a/core/net/ipv4/uip_arp.c
+++ b/core/net/ipv4/uip_arp.c
@@ -284,10 +284,10 @@ uip_arp_arpin(void)
 {
   
   if(uip_len < sizeof(struct arp_hdr)) {
-    uip_len = 0;
+    uip_clear_buf();
     return;
   }
-  uip_len = 0;
+  uip_clear_buf();
   
   switch(BUF->opcode) {
   case UIP_HTONS(ARP_REQUEST):
diff --git a/core/net/ipv6/multicast/roll-tm.c b/core/net/ipv6/multicast/roll-tm.c
index a6b1b8bff..bed0b6b0f 100644
--- a/core/net/ipv6/multicast/roll-tm.c
+++ b/core/net/ipv6/multicast/roll-tm.c
@@ -1383,8 +1383,7 @@ out()
 
 drop:
   uip_slen = 0;
-  uip_len = 0;
-  uip_ext_len = 0;
+  uip_clear_buf();
 }
 /*---------------------------------------------------------------------------*/
 static uint8_t
diff --git a/core/net/ipv6/multicast/smrf.c b/core/net/ipv6/multicast/smrf.c
index b1dccbd19..d62547ef6 100644
--- a/core/net/ipv6/multicast/smrf.c
+++ b/core/net/ipv6/multicast/smrf.c
@@ -81,7 +81,7 @@ mcast_fwd(void *p)
   uip_len = mcast_len;
   UIP_IP_BUF->ttl--;
   tcpip_output(NULL);
-  uip_len = 0;
+  uip_clear_buf();
 }
 /*---------------------------------------------------------------------------*/
 static uint8_t
diff --git a/core/net/ipv6/uip-icmp6.c b/core/net/ipv6/uip-icmp6.c
index ee8d94c77..a9dc9e352 100644
--- a/core/net/ipv6/uip-icmp6.c
+++ b/core/net/ipv6/uip-icmp6.c
@@ -210,12 +210,12 @@ uip_icmp6_error_output(uint8_t type, uint8_t code, uint32_t param) {
  /* check if originating packet is not an ICMP error*/
   if (uip_ext_len) {
     if(UIP_EXT_BUF->next == UIP_PROTO_ICMP6 && UIP_ICMP_BUF->type < 128){
-      uip_len = 0;
+      uip_clear_buf();
       return;
     }
   } else {
     if(UIP_IP_BUF->proto == UIP_PROTO_ICMP6 && UIP_ICMP_BUF->type < 128){
-      uip_len = 0;
+      uip_clear_buf();
       return;
     }
   }
@@ -250,7 +250,7 @@ uip_icmp6_error_output(uint8_t type, uint8_t code, uint32_t param) {
   /* the source should not be unspecified nor multicast, the check for
      multicast is done in uip_process */
   if(uip_is_addr_unspecified(&UIP_IP_BUF->srcipaddr)){
-    uip_len = 0;
+    uip_clear_buf();
     return;
   }
 
@@ -260,7 +260,7 @@ uip_icmp6_error_output(uint8_t type, uint8_t code, uint32_t param) {
     if(type == ICMP6_PARAM_PROB && code == ICMP6_PARAMPROB_OPTION){
       uip_ds6_select_src(&UIP_IP_BUF->srcipaddr, &tmp_ipaddr);
     } else {
-      uip_len = 0;
+      uip_clear_buf();
       return;
     }
   } else {
@@ -385,7 +385,7 @@ echo_reply_input(void)
     }
   }
 
-  uip_len = 0;
+  uip_clear_buf();
   return;
 }
 /*---------------------------------------------------------------------------*/
diff --git a/core/net/ipv6/uip-nd6.c b/core/net/ipv6/uip-nd6.c
index 72b1badfa..331e1fae3 100644
--- a/core/net/ipv6/uip-nd6.c
+++ b/core/net/ipv6/uip-nd6.c
@@ -321,7 +321,7 @@ create_na:
   return;
 
 discard:
-  uip_len = 0;
+  uip_clear_buf();
   return;
 }
 #endif /* UIP_ND6_SEND_NA */
@@ -360,7 +360,7 @@ uip_nd6_ns_output(uip_ipaddr_t * src, uip_ipaddr_t * dest, uip_ipaddr_t * tgt)
     }
     if (uip_is_addr_unspecified(&UIP_IP_BUF->srcipaddr)) {
       PRINTF("Dropping NS due to no suitable source address\n");
-      uip_len = 0;
+      uip_clear_buf();
       return;
     }
     UIP_IP_BUF->len[1] =
@@ -557,7 +557,7 @@ na_input(void)
 #endif /*UIP_CONF_IPV6_QUEUE_PKT */
 
 discard:
-  uip_len = 0;
+  uip_clear_buf();
   return;
 }
 #endif /* UIP_ND6_SEND_NA */
@@ -646,7 +646,7 @@ rs_input(void)
   uip_ds6_send_ra_sollicited();
 
 discard:
-  uip_len = 0;
+  uip_clear_buf();
   return;
 }
 
@@ -1029,7 +1029,7 @@ ra_input(void)
 #endif /*UIP_CONF_IPV6_QUEUE_PKT */
 
 discard:
-  uip_len = 0;
+  uip_clear_buf();
   return;
 }
 #endif /* !UIP_CONF_ROUTER */
diff --git a/core/net/ipv6/uip6.c b/core/net/ipv6/uip6.c
index 73abd1115..416edf813 100644
--- a/core/net/ipv6/uip6.c
+++ b/core/net/ipv6/uip6.c
@@ -538,8 +538,7 @@ remove_ext_hdr(void)
 	   uip_ext_len, uip_len);
     if(uip_len < UIP_IPH_LEN + uip_ext_len) {
       PRINTF("ERROR: uip_len too short compared to ext len\n");
-      uip_ext_len = 0;
-      uip_len = 0;
+      uip_clear_buf();
       return;
     }
     memmove(((uint8_t *)UIP_TCP_BUF), (uint8_t *)UIP_TCP_BUF + uip_ext_len,
@@ -825,8 +824,7 @@ uip_reass_over(void)
      * any RFC, we decided not to include it as it reduces the size of
      * the packet.
      */
-    uip_len = 0;
-    uip_ext_len = 0;
+    uip_clear_buf();
     memcpy(UIP_IP_BUF, FBUF, UIP_IPH_LEN); /* copy the header for src
                                               and dest address*/
     uip_icmp6_error_output(ICMP6_TIME_EXCEEDED, ICMP6_TIME_EXCEED_REASSEMBLY, 0);
@@ -971,7 +969,7 @@ uip_process(uint8_t flag)
   } else if(flag == UIP_TIMER) {
     /* Reset the length variables. */
 #if UIP_TCP
-    uip_len = 0;
+    uip_clear_buf();
     uip_slen = 0;
     
     /* Increase the initial sequence number. */
@@ -1456,7 +1454,7 @@ uip_process(uint8_t flag)
     UIP_STAT(++uip_stat.icmp.drop);
     UIP_STAT(++uip_stat.icmp.typeerr);
     UIP_LOG("icmp6: unknown ICMPv6 message.");
-    uip_len = 0;
+    uip_clear_buf();
   }
   
   if(uip_len > 0) {
@@ -1978,7 +1976,7 @@ uip_process(uint8_t flag)
         uip_add_rcv_nxt(1);
         uip_flags = UIP_CONNECTED | UIP_NEWDATA;
         uip_connr->len = 0;
-        uip_len = 0;
+        uip_clear_buf();
         uip_slen = 0;
         UIP_APPCALL();
         goto appsend;
@@ -2310,8 +2308,7 @@ uip_process(uint8_t flag)
   return;
 
  drop:
-  uip_len = 0;
-  uip_ext_len = 0;
+  uip_clear_buf();
   uip_ext_bitmap = 0;
   uip_flags = 0;
   return;
diff --git a/core/net/rpl/rpl-icmp6.c b/core/net/rpl/rpl-icmp6.c
index 66e311d51..880b7986c 100644
--- a/core/net/rpl/rpl-icmp6.c
+++ b/core/net/rpl/rpl-icmp6.c
@@ -175,7 +175,7 @@ dis_input(void)
       }
     }
   }
-  uip_len = 0;
+  uip_clear_buf();
 }
 /*---------------------------------------------------------------------------*/
 void
@@ -418,7 +418,7 @@ dio_input(void)
 
   rpl_process_dio(&from, &dio);
 
-  uip_len = 0;
+  uip_clear_buf();
 }
 /*---------------------------------------------------------------------------*/
 void
@@ -801,7 +801,7 @@ fwd_dao:
       dao_ack_output(instance, &dao_sender_addr, sequence);
     }
   }
-  uip_len = 0;
+  uip_clear_buf();
 }
 /*---------------------------------------------------------------------------*/
 void
@@ -931,7 +931,7 @@ dao_ack_input(void)
   PRINT6ADDR(&UIP_IP_BUF->srcipaddr);
   PRINTF("\n");
 #endif /* DEBUG */
-  uip_len = 0;
+  uip_clear_buf();
 }
 /*---------------------------------------------------------------------------*/
 void
diff --git a/cpu/native/net/tapdev-drv.c b/cpu/native/net/tapdev-drv.c
index 8a7aeed53..d2d4a1ac0 100644
--- a/cpu/native/net/tapdev-drv.c
+++ b/cpu/native/net/tapdev-drv.c
@@ -83,7 +83,7 @@ pollhandler(void)
        }
 #endif              
     } else {
-      uip_len = 0;
+      uip_clear_buf();
     }
   }
 }
diff --git a/cpu/native/net/wpcap-drv.c b/cpu/native/net/wpcap-drv.c
index 0b3cf926a..7ff8457b6 100644
--- a/cpu/native/net/wpcap-drv.c
+++ b/cpu/native/net/wpcap-drv.c
@@ -103,7 +103,7 @@ pollhandler(void)
        }
 #endif /* !NETSTACK_CONF_WITH_IPV6 */
     } else {
-      uip_len = 0;
+      uip_clear_buf();
     }
   }
 #endif
@@ -146,7 +146,7 @@ pollhandler(void)
 #endif /* !NETSTACK_CONF_WITH_IPV6 */
     } else {
 bail:
-      uip_len = 0;
+      uip_clear_buf();
     }
   }
 #endif
diff --git a/examples/cc2530dk/border-router/border-router.c b/examples/cc2530dk/border-router/border-router.c
index 0df514474..843632b23 100644
--- a/examples/cc2530dk/border-router/border-router.c
+++ b/examples/cc2530dk/border-router/border-router.c
@@ -90,7 +90,7 @@ request_prefix(void) CC_NON_BANKED
   uip_buf[1] = 'P';
   uip_len = 2;
   slip_send();
-  uip_len = 0;
+  uip_clear_buf();
 }
 /*---------------------------------------------------------------------------*/
 /* Set our prefix when we receive one over SLIP */
diff --git a/examples/cc2530dk/border-router/slip-bridge.c b/examples/cc2530dk/border-router/slip-bridge.c
index 98aee3bf9..30bd4a429 100644
--- a/examples/cc2530dk/border-router/slip-bridge.c
+++ b/examples/cc2530dk/border-router/slip-bridge.c
@@ -59,7 +59,7 @@ slip_input_callback(void)
   PRINTF("SIN: %u\n", uip_len);
   if((char)uip_buf[0] == '!') {
     PRINTF("Got configuration message of type %c\n", uip_buf[1]);
-    uip_len = 0;
+    uip_clear_buf();
     if((char)uip_buf[1] == 'P') {
       uip_ipaddr_t prefix;
       /* Here we set a prefix !!! */
diff --git a/examples/ipv6/rpl-border-router/border-router.c b/examples/ipv6/rpl-border-router/border-router.c
index 106107ccb..84943e68f 100644
--- a/examples/ipv6/rpl-border-router/border-router.c
+++ b/examples/ipv6/rpl-border-router/border-router.c
@@ -311,7 +311,7 @@ request_prefix(void)
   uip_buf[1] = 'P';
   uip_len = 2;
   slip_send();
-  uip_len = 0;
+  uip_clear_buf();
 }
 /*---------------------------------------------------------------------------*/
 void
diff --git a/examples/ipv6/rpl-border-router/slip-bridge.c b/examples/ipv6/rpl-border-router/slip-bridge.c
index 52b4a4060..582f626e7 100644
--- a/examples/ipv6/rpl-border-router/slip-bridge.c
+++ b/examples/ipv6/rpl-border-router/slip-bridge.c
@@ -59,7 +59,7 @@ slip_input_callback(void)
  // PRINTF("SIN: %u\n", uip_len);
   if(uip_buf[0] == '!') {
     PRINTF("Got configuration message of type %c\n", uip_buf[1]);
-    uip_len = 0;
+    uip_clear_buf();
     if(uip_buf[1] == 'P') {
       uip_ipaddr_t prefix;
       /* Here we set a prefix !!! */
@@ -85,7 +85,7 @@ slip_input_callback(void)
       slip_send();
       
     }
-    uip_len = 0;
+    uip_clear_buf();
   }
   /* Save the last sender received over SLIP to avoid bouncing the
      packet back if no route is found */
diff --git a/examples/ipv6/slip-radio/slip-radio.c b/examples/ipv6/slip-radio/slip-radio.c
index 255cfefb5..b20e559ec 100644
--- a/examples/ipv6/slip-radio/slip-radio.c
+++ b/examples/ipv6/slip-radio/slip-radio.c
@@ -162,7 +162,7 @@ slip_input_callback(void)
 {
   PRINTF("SR-SIN: %u '%c%c'\n", uip_len, uip_buf[0], uip_buf[1]);
   cmd_input(uip_buf, uip_len);
-  uip_len = 0;
+  uip_clear_buf();
 }
 /*---------------------------------------------------------------------------*/
 static void
diff --git a/examples/ravenusbstick/fakeuip.c b/examples/ravenusbstick/fakeuip.c
index a1e980aab..1f7232a64 100644
--- a/examples/ravenusbstick/fakeuip.c
+++ b/examples/ravenusbstick/fakeuip.c
@@ -13,6 +13,8 @@ uip_buf_t uip_aligned_buf;
 
 uint16_t uip_len;
 
+uint8_t uip_ext_len;
+
 struct uip_stats uip_stat;
 
 uip_lladdr_t uip_lladdr;
diff --git a/examples/sensinode/border-router/border-router.c b/examples/sensinode/border-router/border-router.c
index 028a2f770..9442c9e03 100644
--- a/examples/sensinode/border-router/border-router.c
+++ b/examples/sensinode/border-router/border-router.c
@@ -90,7 +90,7 @@ request_prefix(void) CC_NON_BANKED
   uip_buf[1] = 'P';
   uip_len = 2;
   slip_send();
-  uip_len = 0;
+  uip_clear_buf();
 }
 /*---------------------------------------------------------------------------*/
 /* Set our prefix when we receive one over SLIP */
diff --git a/examples/sensinode/border-router/slip-bridge.c b/examples/sensinode/border-router/slip-bridge.c
index fc9f95a28..edd048a7d 100644
--- a/examples/sensinode/border-router/slip-bridge.c
+++ b/examples/sensinode/border-router/slip-bridge.c
@@ -60,7 +60,7 @@ slip_input_callback(void)
   PRINTF("SIN: %u\n", uip_len);
   if((char)uip_buf[0] == '!') {
     PRINTF("Got configuration message of type %c\n", uip_buf[1]);
-    uip_len = 0;
+    uip_clear_buf();
     if((char)uip_buf[1] == 'P') {
       uip_ipaddr_t prefix;
       /* Here we set a prefix !!! */
diff --git a/platform/avr-ravenusb/sicslow_ethernet.c b/platform/avr-ravenusb/sicslow_ethernet.c
index 46b9244cc..5f70928ba 100644
--- a/platform/avr-ravenusb/sicslow_ethernet.c
+++ b/platform/avr-ravenusb/sicslow_ethernet.c
@@ -342,7 +342,7 @@ void mac_ethernetToLowpan(uint8_t * ethHeader)
 
   /* In sniffer or sneezr mode we don't ever send anything */
   if ((usbstick_mode.sendToRf == 0) || (usbstick_mode.sneeze != 0)) {
-    uip_len = 0;
+    uip_clear_buf();
     return;
   }
 
@@ -354,7 +354,7 @@ void mac_ethernetToLowpan(uint8_t * ethHeader)
 #if !RF230BB
     usb_eth_stat.txbad++;
 #endif
-    uip_len = 0;
+    uip_clear_buf();
     return;
   }
 
@@ -375,7 +375,7 @@ void mac_ethernetToLowpan(uint8_t * ethHeader)
 #if !RF230BB
     usb_eth_stat.txbad++;
 #endif
-    uip_len = 0;
+    uip_clear_buf();
     return;
   } else {
 
@@ -409,7 +409,7 @@ void mac_ethernetToLowpan(uint8_t * ethHeader)
 #if UIP_CONF_SIMPLE_JACKDAW_ADDR_TRANS
   else {
         //Not addressed to us
-        uip_len = 0;
+        uip_clear_buf();
         return;
   }
 #else
@@ -422,7 +422,7 @@ void mac_ethernetToLowpan(uint8_t * ethHeader)
 #if !RF230BB
       usb_eth_stat.txbad++;
 #endif
-      uip_len = 0;
+      uip_clear_buf();
       return;
     }
     PRINTF(" translated OK\n\r");
@@ -463,7 +463,7 @@ void mac_ethernetToLowpan(uint8_t * ethHeader)
 #if !RF230BB
   usb_eth_stat.txok++;
 #endif
-  uip_len = 0;
+  uip_clear_buf();
 
 }
 
@@ -543,7 +543,7 @@ void mac_LowpanToEthernet(void)
 #if !RF230BB
   usb_eth_stat.rxok++;
 #endif
-  uip_len = 0;
+  uip_clear_buf();
 }
 
 /**
diff --git a/tools/cc2538-bsl b/tools/cc2538-bsl
index d6711e24c..1223bfe03 160000
--- a/tools/cc2538-bsl
+++ b/tools/cc2538-bsl
@@ -1 +1 @@
-Subproject commit d6711e24ceeb1de09421166a3dc1b97378648af5
+Subproject commit 1223bfe03cdb31c439f1a51593808cdabc1939d2
diff --git a/tools/sky/uip6-bridge/dev/slip.c b/tools/sky/uip6-bridge/dev/slip.c
index 42d6760b1..4cb65cfd5 100644
--- a/tools/sky/uip6-bridge/dev/slip.c
+++ b/tools/sky/uip6-bridge/dev/slip.c
@@ -294,7 +294,7 @@ PROCESS_THREAD(slip_process, ev, data)
         tcpip_input();
       }
     } else {
-      uip_len = 0;
+      uip_clear_buf();
       SLIP_STATISTICS(slip_ip_drop++);
     }
 #else /* NETSTACK_CONF_WITH_IPV6 */
diff --git a/tools/sky/uip6-bridge/sicslow_ethernet.c b/tools/sky/uip6-bridge/sicslow_ethernet.c
index a74415020..7de0694c3 100644
--- a/tools/sky/uip6-bridge/sicslow_ethernet.c
+++ b/tools/sky/uip6-bridge/sicslow_ethernet.c
@@ -238,13 +238,13 @@ void mac_ethernetToLowpan(uint8_t * ethHeader)
   if (((struct uip_eth_hdr *) ethHeader)->type != UIP_HTONS(UIP_ETHTYPE_IPV6)) {
     PRINTF("eth2low: Packet is not IPv6, dropping\n");
 /*     rndis_stat.txbad++; */
-    uip_len = 0;
+    uip_clear_buf();
     return;
   }
 
   // In sniffer mode we don't ever send anything
   if (usbstick_mode.sendToRf == 0) {
-    uip_len = 0;
+    uip_clear_buf();
     return;
   }
 
@@ -263,7 +263,7 @@ void mac_ethernetToLowpan(uint8_t * ethHeader)
     /* IPv6 does not use broadcast addresses, hence this should not happen */
     PRINTF("eth2low: Ethernet broadcast address received, should not happen?\n");
 /*     rndis_stat.txbad++; */
-    uip_len = 0;
+    uip_clear_buf();
     return;
   } else {
     PRINTF("eth2low: Addressed packet received... ");
@@ -271,7 +271,7 @@ void mac_ethernetToLowpan(uint8_t * ethHeader)
     if (mac_createSicslowpanLongAddr( &(((struct uip_eth_hdr *) ethHeader)->dest.addr[0]), &destAddr) == 0) {
       PRINTF(" translation failed\n");
 /*       rndis_stat.txbad++; */
-      uip_len = 0;
+      uip_clear_buf();
       return;
     }
     PRINTF(" translated OK\n");
@@ -295,7 +295,7 @@ void mac_ethernetToLowpan(uint8_t * ethHeader)
     }
   }
 
-  uip_len = 0;
+  uip_clear_buf();
 
 }
 
@@ -343,7 +343,7 @@ void mac_LowpanToEthernet(void)
 
 /*   rndis_send(uip_buf, uip_len, 1); */
 /*   rndis_stat.rxok++; */
-/*   uip_len = 0; */
+/*   uip_clear_buf(); */
 }
 
 /**
diff --git a/tools/sky/uip6-bridge/uip6-bridge-tap.c b/tools/sky/uip6-bridge/uip6-bridge-tap.c
index f1c5a0256..9aabd752f 100644
--- a/tools/sky/uip6-bridge/uip6-bridge-tap.c
+++ b/tools/sky/uip6-bridge/uip6-bridge-tap.c
@@ -95,7 +95,7 @@ tcpip_input(void)
 	     packetbuf_attr(PACKETBUF_ATTR_LISTEN_TIME));*/
       slip_write(uip_buf, uip_len);
       leds_toggle(LEDS_RED);
-      uip_len = 0;
+      uip_clear_buf();
     }
   }
 }
diff --git a/tools/stm32w/uip6_bridge/dev/slip.c b/tools/stm32w/uip6_bridge/dev/slip.c
index 1380160d1..543896266 100644
--- a/tools/stm32w/uip6_bridge/dev/slip.c
+++ b/tools/stm32w/uip6_bridge/dev/slip.c
@@ -370,7 +370,7 @@ PROCESS_THREAD(slip_process, ev, data)
 					tcpip_input();
 				}
 		} else {
-			uip_len = 0;
+			uip_clear_buf();
 			SLIP_STATISTICS(slip_ip_drop++);
 		}
 #else /* NETSTACK_CONF_WITH_IPV6 */
diff --git a/tools/stm32w/uip6_bridge/sicslow_ethernet.c b/tools/stm32w/uip6_bridge/sicslow_ethernet.c
index 440ed9504..24c2b648c 100644
--- a/tools/stm32w/uip6_bridge/sicslow_ethernet.c
+++ b/tools/stm32w/uip6_bridge/sicslow_ethernet.c
@@ -267,13 +267,13 @@ void mac_ethernetToLowpan(uint8_t * ethHeader)
   if (((struct uip_eth_hdr *) ethHeader)->type != UIP_HTONS(UIP_ETHTYPE_IPV6)) {
     PRINTF("eth2low: Packet is not IPv6, dropping\n");
 /*     rndis_stat.txbad++; */
-    uip_len = 0;
+    uip_clear_buf();
     return;
   }
 
   // In sniffer mode we don't ever send anything
   if (usbstick_mode.sendToRf == 0) {
-    uip_len = 0;
+    uip_clear_buf();
     return;
   }
 
@@ -292,7 +292,7 @@ void mac_ethernetToLowpan(uint8_t * ethHeader)
     /* IPv6 does not use broadcast addresses, hence this should not happen */
     PRINTF("eth2low: Ethernet broadcast address received, should not happen?\n");
 /*     rndis_stat.txbad++; */
-    uip_len = 0;
+    uip_clear_buf();
     return;
   } else {
     PRINTF("eth2low: Addressed packet received... ");
@@ -300,7 +300,7 @@ void mac_ethernetToLowpan(uint8_t * ethHeader)
     if (mac_createSicslowpanLongAddr( &(((struct uip_eth_hdr *) ethHeader)->dest.addr[0]), &destAddr) == 0) {
       PRINTF(" translation failed\n");
 /*       rndis_stat.txbad++; */
-      uip_len = 0;
+      uip_clear_buf();
       return;
     }
     PRINTF(" translated OK\n");
@@ -322,7 +322,7 @@ void mac_ethernetToLowpan(uint8_t * ethHeader)
 /* 	  rndis_stat.txok++; */
   }
 
-  uip_len = 0;
+  uip_clear_buf();
 
 }
 
@@ -370,7 +370,7 @@ void mac_LowpanToEthernet(void)
 
 /*   rndis_send(uip_buf, uip_len, 1); */
 /*   rndis_stat.rxok++; */
-/*   uip_len = 0; */
+/*   uip_clear_buf(); */
 }
 
 /**
diff --git a/tools/stm32w/uip6_bridge/uip6-bridge-tap.c b/tools/stm32w/uip6_bridge/uip6-bridge-tap.c
index 6fea42db2..307d8ea4e 100644
--- a/tools/stm32w/uip6_bridge/uip6-bridge-tap.c
+++ b/tools/stm32w/uip6_bridge/uip6-bridge-tap.c
@@ -98,7 +98,7 @@ tcpip_input(void)
 	     packetbuf_attr(PACKETBUF_ATTR_TRANSMIT_TIME),
 	     packetbuf_attr(PACKETBUF_ATTR_LISTEN_TIME));*/
       slip_write(uip_buf, uip_len);
-      uip_len = 0;
+      uip_clear_buf();
       leds_off(LEDS_RED);
     }
   }