Check if there's something there before we free it

src/mesh/ReliableRouter.cpp

@@ -151,6 +151,7 @@ bool ReliableRouter::stopRetransmission(GlobalPacketId key)
         // remove the 'original' (identified by originator and packet->id) from the txqueue and free it
         cancelSending(getFrom(old->packet), old->packet->id);
         // now free the pooled copy for retransmission too. tryfix for #2228
+        if (old->packet)
             packetPool.release(old->packet);
         return true;
     } else