diff --git a/src/algo_thunder.c b/src/algo_thunder.c
index 469ce5c..0ac5269 100644
--- a/src/algo_thunder.c
+++ b/src/algo_thunder.c
@@ -192,7 +192,7 @@ void classify(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo, struct b
     struct block_info *bi = malloc(sizeof(struct block_info));
     bi->i = i; bi->app_ctx = app_ctx; bi->missing = expected;
 
-    set_timeout (ctx, timeout, &bi, on_block);
+    set_timeout (ctx, timeout, bi, on_block);
     if (ctx->verbose > 1) {
       fprintf(stderr, "    [algo_thunder] Set timeout on link %d of %ld ms (packets expected: %ld, seen: %ld)\n",
               i, timeout, expected, thunderc->received_pkts_on_link[i]);
@@ -245,6 +245,7 @@ void adapt(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo, struct buff
     }
 
     struct buffer_packet *bp_dest = inject_buffer_tow (&app_ctx->br, to_fdinfo);
+    dump_buffer_packet (bp_dest);
     buffer_append_ap (bp_dest, ui->ap_arr_pl[i]);
     main_on_udp_write(ctx, to_fdinfo);
   }
diff --git a/src/packet.c b/src/packet.c
index b6c5a20..c447f3d 100644
--- a/src/packet.c
+++ b/src/packet.c
@@ -1,7 +1,15 @@
 #include "packet.h"
 
+int ap_exists(union abstract_packet* ap) {
+  return ap->fmt.headers.cmd != 0;
+}
+
+int buffer_has_ap(struct buffer_packet* bp) {
+  return ap_exists(buffer_first_ap (bp));
+}
+
 union abstract_packet* ap_next(union abstract_packet* ap) {
-  if (ap->fmt.headers.flags & FLAG_READ_NEXT)
+  if (ap_exists (ap) && ap->fmt.headers.flags & FLAG_READ_NEXT)
     return (union abstract_packet*)(&ap->raw + ap->fmt.headers.size);
 
   return NULL;
@@ -37,7 +45,9 @@ size_t buffer_full_size(struct buffer_packet* bp) {
 }
 
 union abstract_packet* buffer_append_ap(struct buffer_packet* bp, union abstract_packet* ap) {
-  buffer_last_ap(bp)->fmt.headers.flags |= FLAG_READ_NEXT;
+  if (buffer_has_ap (bp))
+    buffer_last_ap(bp)->fmt.headers.flags |= FLAG_READ_NEXT;
+
   union abstract_packet *new_ap = buffer_last_ap(bp);
   memcpy(new_ap, ap, ap->fmt.headers.size);
   bp->ap_count++;