diff --git a/src/api/api_msg.c b/src/api/api_msg.c
index 3f08e038..1a733e6c 100644
--- a/src/api/api_msg.c
+++ b/src/api/api_msg.c
@@ -875,6 +875,9 @@ netconn_drain(struct netconn *conn)
           /* Only tcp pcbs have an acceptmbox, so no need to check conn->type */
           /* pcb might be set to NULL already by err_tcp() */
           /* drain recvmbox */
+#if ESP_LWIP
+          newconn->flags |= NETCONN_FLAG_MBOXINVALID;
+#endif /* ESP_LWIP */
           netconn_drain(newconn);
           if (newconn->pcb.tcp != NULL) {
             tcp_abort(newconn->pcb.tcp);
@@ -1120,6 +1123,9 @@ lwip_netconn_do_delconn(void *m)
   enum netconn_state state = msg->conn->state;
   LWIP_ASSERT("netconn state error", /* this only happens for TCP netconns */
               (state == NETCONN_NONE) || (NETCONNTYPE_GROUP(msg->conn->type) == NETCONN_TCP));
+#if ESP_LWIP
+  msg->err = ERR_OK;
+#endif
 #if LWIP_NETCONN_FULLDUPLEX
   /* In full duplex mode, blocking write/connect is aborted with ERR_CLSD */
   if (state != NETCONN_NONE) {
@@ -1132,6 +1138,9 @@ lwip_netconn_do_delconn(void *m)
       msg->conn->current_msg->err = ERR_CLSD;
       msg->conn->current_msg = NULL;
       msg->conn->state = NETCONN_NONE;
+#if ESP_LWIP
+      msg->err = ERR_INPROGRESS;
+#endif
       sys_sem_signal(op_completed_sem);
     }
   }
@@ -1146,9 +1155,11 @@ lwip_netconn_do_delconn(void *m)
   } else
 #endif /* LWIP_NETCONN_FULLDUPLEX */
   {
+#if !ESP_LWIP
     LWIP_ASSERT("blocking connect in progress",
                 (state != NETCONN_CONNECT) || IN_NONBLOCKING_CONNECT(msg->conn));
     msg->err = ERR_OK;
+#endif /* ESP_LWIP */
 #if LWIP_NETCONN_FULLDUPLEX
     /* Mark mboxes invalid */
     netconn_mark_mbox_invalid(msg->conn);
diff --git a/test/unit/lwipopts.h b/test/unit/lwipopts.h
index e4523fc1..e2d815fd 100644
--- a/test/unit/lwipopts.h
+++ b/test/unit/lwipopts.h
@@ -83,4 +83,7 @@
 /* Check lwip_stats.mem.illegal instead of asserting */
 #define LWIP_MEM_ILLEGAL_FREE(msg)      /* to nothing */
 
+/* Enable Espressif specific options */
+#define ESP_LWIP                        1
+
 #endif /* LWIP_HDR_LWIPOPTS_H */