diff --git a/sw/airborne/subsystems/datalink/datalink.h b/sw/airborne/subsystems/datalink/datalink.h
index 1ec00307ef..e8fe6bfef6 100644
--- a/sw/airborne/subsystems/datalink/datalink.h
+++ b/sw/airborne/subsystems/datalink/datalink.h
@@ -46,6 +46,7 @@
 #define PPRZ 1
 #define XBEE 2
 #define SUPERBITRF 3
+#define W5100 4
 
 EXTERN bool_t dl_msg_available;
 /** Flag provided to control calls to ::dl_parse_msg. NOT used in this module*/
diff --git a/sw/airborne/subsystems/datalink/downlink.c b/sw/airborne/subsystems/datalink/downlink.c
index d83050baba..58d5f8a73c 100644
--- a/sw/airborne/subsystems/datalink/downlink.c
+++ b/sw/airborne/subsystems/datalink/downlink.c
@@ -63,7 +63,7 @@ void downlink_init(void)
   downlink.nb_msgs = 0;
 
 #if defined DATALINK
-#if DATALINK == PPRZ
+#if DATALINK == PPRZ || DATALINK == SUPERBITRF || DATALINK == W5100
   pprz_transport_init();
 #endif
 #if DATALINK == XBEE
diff --git a/sw/airborne/subsystems/datalink/superbitrf.c b/sw/airborne/subsystems/datalink/superbitrf.c
index 760594bf4e..2cd58c2ee3 100644
--- a/sw/airborne/subsystems/datalink/superbitrf.c
+++ b/sw/airborne/subsystems/datalink/superbitrf.c
@@ -200,15 +200,18 @@ static void send_superbit(struct transport_tx *trans, struct link_device *dev) {
 #endif
 
 // Functions for the generic device API
-static int superbitrf_check_free_space(struct SuperbitRF* p __attribute__((unused)), uint8_t len __attribute__((unused)))
+static bool_t superbitrf_check_free_space(struct SuperbitRF* p, uint8_t len)
 {
-  return (((superbitrf.tx_insert_idx+1) %128) != superbitrf.tx_extract_idx);
+  int16_t space = p->tx_extract_idx - p->tx_insert_idx;
+  if (space <= 0)
+    space += SUPERBITRF_TX_BUFFER_SIZE;
+  return (uint16_t)(space - 1) >= len;
 }
 
-static void superbitrf_transmit(struct SuperbitRF* p __attribute__((unused)), uint8_t byte)
+static void superbitrf_transmit(struct SuperbitRF* p, uint8_t byte)
 {
-  superbitrf.tx_buffer[superbitrf.tx_insert_idx] = byte;
-  superbitrf.tx_insert_idx = (superbitrf.tx_insert_idx+1) %128;
+  p->tx_buffer[p->tx_insert_idx] = byte;
+  p->tx_insert_idx = (p->tx_insert_idx+1) %SUPERBITRF_TX_BUFFER_SIZE;
 }
 
 static void superbitrf_send(struct SuperbitRF* p __attribute__((unused))) { }
@@ -506,12 +509,12 @@ void superbitrf_event(void) {
           tx_packet[1] = (superbitrf.bind_mfg_id[3])+1+superbitrf.packet_loss_bit;
         }
 
-        packet_size = (superbitrf.tx_insert_idx-superbitrf.tx_extract_idx+128 %128);
+        packet_size = (superbitrf.tx_insert_idx-superbitrf.tx_extract_idx+SUPERBITRF_TX_BUFFER_SIZE %SUPERBITRF_TX_BUFFER_SIZE);
         if(packet_size > 14)
           packet_size = 14;
 
         for(i = 0; i < packet_size; i++)
-          tx_packet[i+2] = superbitrf.tx_buffer[(superbitrf.tx_extract_idx+i) %128];
+          tx_packet[i+2] = superbitrf.tx_buffer[(superbitrf.tx_extract_idx+i) %SUPERBITRF_TX_BUFFER_SIZE];
       }
 
       // Send a packet
@@ -519,7 +522,7 @@ void superbitrf_event(void) {
 
       // Update the packet extraction
       if(!superbitrf.packet_loss)
-        superbitrf.tx_extract_idx = (superbitrf.tx_extract_idx+packet_size) %128;
+        superbitrf.tx_extract_idx = (superbitrf.tx_extract_idx+packet_size) %SUPERBITRF_TX_BUFFER_SIZE;
 
       superbitrf.state++;
       break;
@@ -632,12 +635,12 @@ void superbitrf_event(void) {
           tx_packet[1] = ((superbitrf.bind_mfg_id[3])+1+superbitrf.packet_loss_bit) % 0xFF;
         }
 
-        packet_size = (superbitrf.tx_insert_idx-superbitrf.tx_extract_idx+128 %128);
+        packet_size = (superbitrf.tx_insert_idx-superbitrf.tx_extract_idx+SUPERBITRF_TX_BUFFER_SIZE %SUPERBITRF_TX_BUFFER_SIZE);
         if(packet_size > 14)
           packet_size = 14;
 
         for(i = 0; i < packet_size; i++)
-          tx_packet[i+2] = superbitrf.tx_buffer[(superbitrf.tx_extract_idx+i) %128];
+          tx_packet[i+2] = superbitrf.tx_buffer[(superbitrf.tx_extract_idx+i) %SUPERBITRF_TX_BUFFER_SIZE];
       }
 
       // Send a packet
@@ -645,7 +648,7 @@ void superbitrf_event(void) {
 
       // Update the packet extraction
       if(!superbitrf.packet_loss)
-        superbitrf.tx_extract_idx = (superbitrf.tx_extract_idx+packet_size) %128;
+        superbitrf.tx_extract_idx = (superbitrf.tx_extract_idx+packet_size) %SUPERBITRF_TX_BUFFER_SIZE;
 
       superbitrf.state++;
       break;
diff --git a/sw/airborne/subsystems/datalink/superbitrf.h b/sw/airborne/subsystems/datalink/superbitrf.h
index 1bba6ffd7c..afb73e5482 100644
--- a/sw/airborne/subsystems/datalink/superbitrf.h
+++ b/sw/airborne/subsystems/datalink/superbitrf.h
@@ -70,6 +70,8 @@ enum dsm_protocol {
 #define IS_DSM2(x)          (x == DSM_DSM2P || x == DSM_DSM2_1 || x == DSM_DSM2_2)
 #define IS_DSMX(x)          (!IS_DSM2(x))
 
+#define SUPERBITRF_TX_BUFFER_SIZE 128
+
 /* The superbitrf structure */
 struct SuperbitRF {
   struct Cyrf6936 cyrf6936;                 /**< The cyrf chip used */
@@ -108,7 +110,7 @@ struct SuperbitRF {
 
   struct pprz_transport rx_transport;       /**< The receive transport */
 
-  uint8_t tx_buffer[128];                   /**< The transmit buffer */
+  uint8_t tx_buffer[SUPERBITRF_TX_BUFFER_SIZE]; /**< The transmit buffer */
   uint8_t tx_insert_idx;                    /**< The transmit buffer insert index */
   uint8_t tx_extract_idx;                   /**< The transmit buffer extract index */
 
@@ -125,10 +127,10 @@ extern void superbitrf_set_protocol(uint8_t protocol);
 
 /* The datalink defines */
 #define SuperbitRFInit() { }//superbitrf_init(); }
-#define SuperbitRFCheckFreeSpace(_x) (((superbitrf.tx_insert_idx+1) %128) != superbitrf.tx_extract_idx)
+#define SuperbitRFCheckFreeSpace(_x) (((superbitrf.tx_insert_idx+1) %SUPERBITRF_TX_BUFFER_SIZE) != superbitrf.tx_extract_idx)
 #define SuperbitRFTransmit(_x) {                                    \
     superbitrf.tx_buffer[superbitrf.tx_insert_idx] = _x;            \
-    superbitrf.tx_insert_idx = (superbitrf.tx_insert_idx+1) %128;   \
+    superbitrf.tx_insert_idx = (superbitrf.tx_insert_idx+1) %SUPERBITRF_TX_BUFFER_SIZE;   \
   }
 #define SuperbitRFSendMessage() { }
 #define SuperbitRFCheckAndParse() { }