diff --git a/mavlink.c b/mavlink.c
index ef8326eb..8681a647 100644
--- a/mavlink.c
+++ b/mavlink.c
@@ -212,14 +212,14 @@ int mavlink_parse(struct slip_decode_state *state)
   if (packet_length==9){
     if (state->mavlink_payload[5]==MAVLINK_MSG_ID_RADIO){
       // we can assume that radio status packets arrive without corruption
-      last_radio_rssi=(1.0*state->mavlink_payload[6+5]-state->mavlink_payload[6+8])/1.9;
+      last_radio_rssi=(1.0*state->mavlink_payload[10]-state->mavlink_payload[13])/1.9;
       last_radio_temperature=-999; // doesn't get reported
       last_radio_rxpackets=-999; // doesn't get reported
       if (config.debug.mavlink||gettime_ms()-last_rssi_time>30000) {
-	INFOF("Link budget = %+ddB, remote link budget = %+ddB, buffer space = %d",
+	INFOF("Link budget = %+ddB, remote link budget = %+ddB, buffer space = %d%%",
 	      last_radio_rssi,
-	      (int)((1.0*state->mavlink_payload[6+6]-state->mavlink_payload[6+9])/1.9),
-	      state->mavlink_payload[6+7]);
+	      (int)((1.0*state->mavlink_payload[11]-state->mavlink_payload[14])/1.9),
+	      state->mavlink_payload[12]);
 	last_rssi_time=gettime_ms();
       }
     }
diff --git a/overlay_interface.c b/overlay_interface.c
index b0502a7d..887b75d3 100644
--- a/overlay_interface.c
+++ b/overlay_interface.c
@@ -497,9 +497,6 @@ overlay_interface_init(const char *name, struct in_addr src_addr, struct in_addr
          be safe on the RFD900 radios, and that also allows us to receive RSSI reports inline */
       interface->slip_decode_state.encapsulator=SLIP_FORMAT_MAVLINK;
       interface->alarm.poll.events=POLLIN|POLLOUT;
-      // Queue a hearbeat now
-      interface->tx_bytes_pending=0;
-      mavlink_heartbeat(interface->txbuffer,&interface->tx_bytes_pending);
       watch(&interface->alarm);
 
       break;
@@ -734,11 +731,17 @@ static void write_stream_buffer(overlay_interface *interface){
     int total_written=0;
     while ((interface->tx_bytes_pending>0 || interface->tx_packet) && 
       (bytes_allowed>0 || interface->throttle_burst_write_size==0)) {
+	
       if (interface->tx_bytes_pending==0 && interface->tx_packet){
-	// TODO firmware heartbeat packets
-	// prepare a new link layer packet in txbuffer
-	if (mavlink_encode_packet(interface))
-	  break;
+	if (interface->next_heartbeat <= now){
+	  // Queue a hearbeat now
+	  mavlink_heartbeat(interface->txbuffer,&interface->tx_bytes_pending);
+	  interface->next_heartbeat = now+1000;
+	}else{
+	  // prepare a new link layer packet in txbuffer
+	  if (mavlink_encode_packet(interface))
+	    break;
+	}
       }
     
       int bytes = interface->tx_bytes_pending;
@@ -783,8 +786,6 @@ static void write_stream_buffer(overlay_interface *interface){
   } else {
     // Nothing to write, so clear POLLOUT flag
     interface->alarm.poll.events&=~POLLOUT;
-    // try to empty another packet from the queue ASAP
-    overlay_queue_schedule_next(gettime_ms());
   }
   watch(&interface->alarm);
 }
diff --git a/rhizome_packetformats.c b/rhizome_packetformats.c
index 1852d969..621b7c69 100644
--- a/rhizome_packetformats.c
+++ b/rhizome_packetformats.c
@@ -329,13 +329,12 @@ int overlay_rhizome_saw_advertisements(int i, struct decode_context *context, st
 	WHY("Error parsing manifest body");
 	goto next;
       }
-      const char *id=alloca_tohex_bid(m->cryptoSignPublic);
       
       /* trim manifest ID to a prefix for ease of debugging
 	 (that is the only use of this */
       if (config.debug.rhizome_ads){
 	long long version = rhizome_manifest_get_ll(m, "version");
-	DEBUGF("manifest id=%s version=%lld", id, version);
+	DEBUGF("manifest id=%s version=%lld", alloca_tohex_bid(m->cryptoSignPublic), version);
       }
 
       /* Crude signature presence test */
@@ -352,11 +351,10 @@ int overlay_rhizome_saw_advertisements(int i, struct decode_context *context, st
 	goto next;
       }
 
-      if (rhizome_ignore_manifest_check(m->cryptoSignPublic,
-					crypto_sign_edwards25519sha512batch_PUBLICKEYBYTES)){
+      if (rhizome_ignore_manifest_check(m->cryptoSignPublic, RHIZOME_MANIFEST_ID_BYTES)){
 	/* Ignoring manifest that has caused us problems recently */
 	if (config.debug.rhizome_ads)
-	  DEBUGF("Ignoring manifest with errors: %s", id);
+	  DEBUGF("Ignoring manifest with errors: %s", alloca_tohex_bid(m->cryptoSignPublic));
 	goto next;
       }
 
@@ -366,13 +364,13 @@ int overlay_rhizome_saw_advertisements(int i, struct decode_context *context, st
 	/* Don't waste any time on this manifest in future attempts for at least
 	     a minute. */
 	rhizome_queue_ignore_manifest(m->cryptoSignPublic,
-					crypto_sign_edwards25519sha512batch_PUBLICKEYBYTES, 60000);
+					RHIZOME_MANIFEST_ID_BYTES, 60000);
 	goto next;
       }
       /* Manifest is okay, so see if it is worth storing */
 
       // are we already fetching this bundle [or later]?
-      rhizome_manifest *mf=rhizome_fetch_search(id, crypto_sign_edwards25519sha512batch_PUBLICKEYBYTES);
+      rhizome_manifest *mf=rhizome_fetch_search(m->cryptoSignPublic, RHIZOME_MANIFEST_ID_BYTES);
       if (mf && mf->version >= m->version)
 	goto next;
 	
diff --git a/serval.h b/serval.h
index e970e5e7..cb90ab89 100644
--- a/serval.h
+++ b/serval.h
@@ -454,6 +454,7 @@ typedef struct overlay_interface {
   uint32_t throttle_bytes_per_second;
   uint32_t throttle_burst_write_size;
   uint64_t next_tx_allowed;
+  time_ms_t next_heartbeat;
   
   
   struct slip_decode_state slip_decode_state;