diff --git a/app/cjson/cjson_mem.c b/app/cjson/cjson_mem.c
index 90361633..092cb788 100644
--- a/app/cjson/cjson_mem.c
+++ b/app/cjson/cjson_mem.c
@@ -2,19 +2,14 @@
 #include "../lua/lauxlib.h"
 #include <c_stdlib.h>
 
-static lua_State *gL;
 static const char errfmt[] = "cjson %salloc: out of mem (%d bytes)";
 
-void cjson_mem_setlua (lua_State *L)
-{
-  gL = L;
-}
-
 void *cjson_mem_malloc (uint32_t sz)
 {
   void *p = (void*)c_malloc (sz);
-  if (!p && gL)
-    luaL_error (gL, errfmt, "m", sz);
+  lua_State *L = lua_getstate();
+  if (!p)
+    luaL_error (L, errfmt, "m", sz);
   return p;
 }
 
@@ -22,7 +17,8 @@ void *cjson_mem_malloc (uint32_t sz)
 void *cjson_mem_realloc (void *o, uint32_t sz)
 {
   void *p = (void*)c_realloc (o, sz);
-  if (!p && gL)
-    luaL_error (gL, errfmt, "re", sz);
+  lua_State *L = lua_getstate();
+  if (!p)
+    luaL_error (L, errfmt, "re", sz);
   return p;
 }
diff --git a/app/cjson/cjson_mem.h b/app/cjson/cjson_mem.h
index beefb6c2..ad14e1b2 100644
--- a/app/cjson/cjson_mem.h
+++ b/app/cjson/cjson_mem.h
@@ -3,8 +3,6 @@
 
 #include "../lua/lua.h"
 
-void cjson_mem_setlua (lua_State *L);
-
 void *cjson_mem_malloc (uint32_t sz);
 void *cjson_mem_realloc (void *p, uint32_t sz);
 
diff --git a/app/coap/coap.h b/app/coap/coap.h
index dc4bb6d9..68f2f69a 100644
--- a/app/coap/coap.h
+++ b/app/coap/coap.h
@@ -155,7 +155,6 @@ typedef struct
 typedef struct coap_luser_entry coap_luser_entry;
 
 struct coap_luser_entry{
-    lua_State *L;
     // int ref;
     // char name[MAX_SEGMENTS_SIZE+1];         // +1 for string '\0'
     const char *name;
diff --git a/app/coap/endpoints.c b/app/coap/endpoints.c
index 00705f93..81e124cc 100644
--- a/app/coap/endpoints.c
+++ b/app/coap/endpoints.c
@@ -37,6 +37,7 @@ static int handle_get_variable(const coap_endpoint_t *ep, coap_rw_buffer_t *scra
     const coap_option_t *opt;
     uint8_t count;
     int n;
+    lua_State *L = lua_getstate();
     if (NULL != (opt = coap_findOptions(inpkt, COAP_OPTION_URI_PATH, &count)))
     {
         if ((count != ep->path->count ) && (count != ep->path->count + 1)) // +1 for /f/[function], /v/[variable]
@@ -58,19 +59,17 @@ static int handle_get_variable(const coap_endpoint_t *ep, coap_rw_buffer_t *scra
                     NODE_DBG("/v1/v/");
                     NODE_DBG((char *)h->name);
                     NODE_DBG(" match.\n");
-                    if(h->L == NULL)
-                        return coap_make_response(scratch, outpkt, NULL, 0, id_hi, id_lo, &inpkt->tok, COAP_RSPCODE_NOT_FOUND, COAP_CONTENTTYPE_NONE);
                     if(c_strlen(h->name))
                     {
-                        n = lua_gettop(h->L);
-                        lua_getglobal(h->L, h->name);
-                        if (!lua_isnumber(h->L, -1) && !lua_isstring(h->L, -1)) {
+                        n = lua_gettop(L);
+                        lua_getglobal(L, h->name);
+                        if (!lua_isnumber(L, -1) && !lua_isstring(L, -1)) {
                             NODE_DBG ("should be a number or string.\n");
-                            lua_settop(h->L, n);
+                            lua_settop(L, n);
                             return coap_make_response(scratch, outpkt, NULL, 0, id_hi, id_lo, &inpkt->tok, COAP_RSPCODE_NOT_FOUND, COAP_CONTENTTYPE_NONE);
                         } else {
-                            const char *res = lua_tostring(h->L,-1);
-                            lua_settop(h->L, n);
+                            const char *res = lua_tostring(L,-1);
+                            lua_settop(L, n);
                             return coap_make_response(scratch, outpkt, (const uint8_t *)res, c_strlen(res), id_hi, id_lo, &inpkt->tok, COAP_RSPCODE_CONTENT, h->content_type);
                         }
                     }
@@ -94,6 +93,7 @@ static int handle_post_function(const coap_endpoint_t *ep, coap_rw_buffer_t *scr
     const coap_option_t *opt;
     uint8_t count;
     int n;
+    lua_State *L = lua_getstate();
     if (NULL != (opt = coap_findOptions(inpkt, COAP_OPTION_URI_PATH, &count)))
     {
         if ((count != ep->path->count ) && (count != ep->path->count + 1)) // +1 for /f/[function], /v/[variable]
@@ -116,37 +116,34 @@ static int handle_post_function(const coap_endpoint_t *ep, coap_rw_buffer_t *scr
                     NODE_DBG((char *)h->name);
                     NODE_DBG(" match.\n");
 
-                    if(h->L == NULL)
-                        return coap_make_response(scratch, outpkt, NULL, 0, id_hi, id_lo, &inpkt->tok, COAP_RSPCODE_NOT_FOUND, COAP_CONTENTTYPE_NONE);
-
                     if(c_strlen(h->name))
                     {
-                        n = lua_gettop(h->L);
-                        lua_getglobal(h->L, h->name);
-                        if (lua_type(h->L, -1) != LUA_TFUNCTION) {
+                        n = lua_gettop(L);
+                        lua_getglobal(L, h->name);
+                        if (lua_type(L, -1) != LUA_TFUNCTION) {
                             NODE_DBG ("should be a function\n");
-                            lua_settop(h->L, n);
+                            lua_settop(L, n);
                             return coap_make_response(scratch, outpkt, NULL, 0, id_hi, id_lo, &inpkt->tok, COAP_RSPCODE_NOT_FOUND, COAP_CONTENTTYPE_NONE);
                         } else {
-                            lua_pushlstring(h->L, inpkt->payload.p, inpkt->payload.len);     // make sure payload.p is filled with '\0' after payload.len, or use lua_pushlstring
-                            lua_call(h->L, 1, 1);
-                            if (!lua_isnil(h->L, -1)){  /* get return? */
-                                if( lua_isstring(h->L, -1) )   // deal with the return string
+                            lua_pushlstring(L, inpkt->payload.p, inpkt->payload.len);     // make sure payload.p is filled with '\0' after payload.len, or use lua_pushlstring
+                            lua_call(L, 1, 1);
+                            if (!lua_isnil(L, -1)){  /* get return? */
+                                if( lua_isstring(L, -1) )   // deal with the return string
                                 {
                                     size_t len = 0;
-                                    const char *ret = luaL_checklstring( h->L, -1, &len );
+                                    const char *ret = luaL_checklstring( L, -1, &len );
                                     if(len > MAX_PAYLOAD_SIZE){
-                                        lua_settop(h->L, n);
-                                        luaL_error( h->L, "return string:<MAX_PAYLOAD_SIZE" );
+                                        lua_settop(L, n);
+                                        luaL_error( L, "return string:<MAX_PAYLOAD_SIZE" );
                                         return coap_make_response(scratch, outpkt, NULL, 0, id_hi, id_lo, &inpkt->tok, COAP_RSPCODE_NOT_FOUND, COAP_CONTENTTYPE_NONE);
                                     }
                                     NODE_DBG((char *)ret);
                                     NODE_DBG("\n");
-                                    lua_settop(h->L, n);
+                                    lua_settop(L, n);
                                     return coap_make_response(scratch, outpkt, ret, len, id_hi, id_lo, &inpkt->tok, COAP_RSPCODE_CONTENT, COAP_CONTENTTYPE_TEXT_PLAIN);
                                 } 
                             } else {
-                                lua_settop(h->L, n);
+                                lua_settop(L, n);
                                 return coap_make_response(scratch, outpkt, NULL, 0, id_hi, id_lo, &inpkt->tok, COAP_RSPCODE_CONTENT, COAP_CONTENTTYPE_TEXT_PLAIN);
                             }
                         }
@@ -198,10 +195,10 @@ static int handle_get_id(const coap_endpoint_t *ep, coap_rw_buffer_t *scratch, c
     return coap_make_response(scratch, outpkt, (const uint8_t *)(&id), sizeof(uint32_t), id_hi, id_lo, &inpkt->tok, COAP_RSPCODE_CONTENT, COAP_CONTENTTYPE_TEXT_PLAIN);
 }
 
-coap_luser_entry var_head = {NULL,NULL,NULL,0};
+coap_luser_entry var_head = {NULL,NULL,0};
 coap_luser_entry *variable_entry = &var_head;
 
-coap_luser_entry func_head = {NULL,NULL,NULL,0};
+coap_luser_entry func_head = {NULL,NULL,0};
 coap_luser_entry *function_entry = &func_head;
 
 const coap_endpoint_t endpoints[] =
diff --git a/app/modules/bme280.c b/app/modules/bme280.c
index dea3f5b5..898a7e64 100644
--- a/app/modules/bme280.c
+++ b/app/modules/bme280.c
@@ -304,7 +304,7 @@ static int bme280_lua_init(lua_State* L) {
 static void bme280_readoutdone (void *arg)
 {
 	NODE_DBG("timer out\n");
-	lua_State *L = arg;
+	lua_State *L = lua_getstate();
 	lua_rawgeti (L, LUA_REGISTRYINDEX, lua_connected_readout_ref);
 	lua_call (L, 0, 0);
 	luaL_unref (L, LUA_REGISTRYINDEX, lua_connected_readout_ref);
diff --git a/app/modules/cjson.c b/app/modules/cjson.c
index ec769e04..ed7a31eb 100644
--- a/app/modules/cjson.c
+++ b/app/modules/cjson.c
@@ -1617,8 +1617,6 @@ static const LUA_REG_TYPE cjson_map[] = {
 
 int luaopen_cjson( lua_State *L )
 {
-  cjson_mem_setlua (L);
-
   /* Initialise number conversions */
   // fpconv_init();         // not needed for a specific cpu.
   if(-1==cfg_init(&_cfg)){
diff --git a/app/modules/coap.c b/app/modules/coap.c
index 20b2d7a7..ce683e0c 100644
--- a/app/modules/coap.c
+++ b/app/modules/coap.c
@@ -24,7 +24,6 @@ coap_queue_t *gQueue = NULL;
 
 typedef struct lcoap_userdata
 {
-  lua_State *L;
   struct espconn *pesp_conn;
   int self_ref;
 }lcoap_userdata;
@@ -103,7 +102,6 @@ static int coap_create( lua_State* L, const char* mt )
   pesp_conn->state = ESPCONN_NONE;
   NODE_DBG("UDP server/client is set.\n");
 
-  cud->L = L;
   pesp_conn->reverse = cud;
 
   NODE_DBG("coap_create is called.\n");
@@ -129,7 +127,6 @@ static int coap_delete( lua_State* L, const char* mt )
     cud->self_ref = LUA_NOREF;
   }
 
-  cud->L = NULL;
   if(cud->pesp_conn)
   {
     if(cud->pesp_conn->proto.udp->remote_port || cud->pesp_conn->proto.udp->local_port)
@@ -462,10 +459,8 @@ static int coap_regist( lua_State* L, const char* mt, int isvar )
       return luaL_error(L, "not enough memory");
     h->next = NULL;
     h->name = NULL;
-    h->L = NULL;
   }  
 
-  h->L = L;
   h->name = name;
   h->content_type = content_type;
 
diff --git a/app/modules/net.c b/app/modules/net.c
index 8181b947..b9549487 100644
--- a/app/modules/net.c
+++ b/app/modules/net.c
@@ -34,7 +34,6 @@ static int expose_array(lua_State* L, char *array, unsigned short len);
 #define MAX_SOCKET 5
 static int socket_num = 0;
 static int socket[MAX_SOCKET];
-static lua_State *gL = NULL;
 static int tcpserver_cb_connect_ref = LUA_NOREF;  // for tcp server connected callback
 static uint16_t tcp_server_timeover = 30;
 
@@ -65,8 +64,7 @@ static void net_server_disconnected(void *arg)    // for tcp server only
   lnet_userdata *nud = (lnet_userdata *)pesp_conn->reverse;
   if(nud == NULL)
     return;
-  if(gL == NULL)
-    return;
+  lua_State *L = lua_getstate();
 #if 0
   char temp[20] = {0};
   c_sprintf(temp, IPSTR, IP2STR( &(pesp_conn->proto.tcp->remote_ip) ) );
@@ -78,25 +76,25 @@ static void net_server_disconnected(void *arg)    // for tcp server only
 #endif
   if(nud->cb_disconnect_ref != LUA_NOREF && nud->self_ref != LUA_NOREF)
   {
-    lua_rawgeti(gL, LUA_REGISTRYINDEX, nud->cb_disconnect_ref);
-    lua_rawgeti(gL, LUA_REGISTRYINDEX, nud->self_ref);  // pass the userdata(client) to callback func in lua
-    lua_call(gL, 1, 0);
+    lua_rawgeti(L, LUA_REGISTRYINDEX, nud->cb_disconnect_ref);
+    lua_rawgeti(L, LUA_REGISTRYINDEX, nud->self_ref);  // pass the userdata(client) to callback func in lua
+    lua_call(L, 1, 0);
   }
   int i;
-  lua_gc(gL, LUA_GCSTOP, 0);
+  lua_gc(L, LUA_GCSTOP, 0);
   for(i=0;i<MAX_SOCKET;i++){
     if( (LUA_NOREF!=socket[i]) && (socket[i] == nud->self_ref) ){
       // found the saved client
       nud->pesp_conn->reverse = NULL;
       nud->pesp_conn = NULL;    // the espconn is made by low level sdk, do not need to free, delete() will not free it.
       nud->self_ref = LUA_NOREF;   // unref this, and the net.socket userdata will delete it self
-      luaL_unref(gL, LUA_REGISTRYINDEX, socket[i]);
+      luaL_unref(L, LUA_REGISTRYINDEX, socket[i]);
       socket[i] = LUA_NOREF;
       socket_num--;
       break;
     }
   }
-  lua_gc(gL, LUA_GCRESTART, 0);
+  lua_gc(L, LUA_GCRESTART, 0);
 }
 
 static void net_socket_disconnected(void *arg)    // tcp only
@@ -108,11 +106,12 @@ static void net_socket_disconnected(void *arg)    // tcp only
   lnet_userdata *nud = (lnet_userdata *)pesp_conn->reverse;
   if(nud == NULL)
     return;
+  lua_State *L = lua_getstate();
   if(nud->cb_disconnect_ref != LUA_NOREF && nud->self_ref != LUA_NOREF)
   {
-    lua_rawgeti(gL, LUA_REGISTRYINDEX, nud->cb_disconnect_ref);
-    lua_rawgeti(gL, LUA_REGISTRYINDEX, nud->self_ref);  // pass the userdata(client) to callback func in lua
-    lua_call(gL, 1, 0);
+    lua_rawgeti(L, LUA_REGISTRYINDEX, nud->cb_disconnect_ref);
+    lua_rawgeti(L, LUA_REGISTRYINDEX, nud->self_ref);  // pass the userdata(client) to callback func in lua
+    lua_call(L, 1, 0);
   }
 
   if(pesp_conn->proto.tcp)
@@ -121,12 +120,12 @@ static void net_socket_disconnected(void *arg)    // tcp only
   if(nud->pesp_conn)
     c_free(nud->pesp_conn);
   nud->pesp_conn = NULL;  // espconn is already disconnected
-  lua_gc(gL, LUA_GCSTOP, 0);
+  lua_gc(L, LUA_GCSTOP, 0);
   if(nud->self_ref != LUA_NOREF){
-    luaL_unref(gL, LUA_REGISTRYINDEX, nud->self_ref);
+    luaL_unref(L, LUA_REGISTRYINDEX, nud->self_ref);
     nud->self_ref = LUA_NOREF; // unref this, and the net.socket userdata will delete it self
   }
-  lua_gc(gL, LUA_GCRESTART, 0);
+  lua_gc(L, LUA_GCRESTART, 0);
 }
 
 static void net_server_reconnected(void *arg, sint8_t err)
@@ -154,15 +153,16 @@ static void net_socket_received(void *arg, char *pdata, unsigned short len)
     return;
   if(nud->self_ref == LUA_NOREF)
     return;
-  lua_rawgeti(gL, LUA_REGISTRYINDEX, nud->cb_receive_ref);
-  lua_rawgeti(gL, LUA_REGISTRYINDEX, nud->self_ref);  // pass the userdata(server) to callback func in lua
-  // expose_array(gL, pdata, len);
+  lua_State *L = lua_getstate();
+  lua_rawgeti(L, LUA_REGISTRYINDEX, nud->cb_receive_ref);
+  lua_rawgeti(L, LUA_REGISTRYINDEX, nud->self_ref);  // pass the userdata(server) to callback func in lua
+  // expose_array(L, pdata, len);
   // *(pdata+len) = 0;
   // NODE_DBG(pdata);
   // NODE_DBG("\n");
-  lua_pushlstring(gL, pdata, len);
-  // lua_pushinteger(gL, len);
-  lua_call(gL, 2, 0);
+  lua_pushlstring(L, pdata, len);
+  // lua_pushinteger(L, len);
+  lua_call(L, 2, 0);
 }
 
 static void net_socket_sent(void *arg)
@@ -178,9 +178,10 @@ static void net_socket_sent(void *arg)
     return;
   if(nud->self_ref == LUA_NOREF)
     return;
-  lua_rawgeti(gL, LUA_REGISTRYINDEX, nud->cb_send_ref);
-  lua_rawgeti(gL, LUA_REGISTRYINDEX, nud->self_ref);  // pass the userdata(server) to callback func in lua
-  lua_call(gL, 1, 0);
+  lua_State *L = lua_getstate();
+  lua_rawgeti(L, LUA_REGISTRYINDEX, nud->cb_send_ref);
+  lua_rawgeti(L, LUA_REGISTRYINDEX, nud->self_ref);  // pass the userdata(server) to callback func in lua
+  lua_call(L, 1, 0);
 }
 
 static void net_dns_found(const char *name, ip_addr_t *ipaddr, void *arg)
@@ -205,34 +206,16 @@ static void net_dns_found(const char *name, ip_addr_t *ipaddr, void *arg)
     NODE_DBG("self_ref null.\n");
     return;
   }
-/* original
-  if(ipaddr == NULL)
-  {
-    NODE_ERR( "DNS Fail!\n" );
-    goto end;
-  }
-  // ipaddr->addr is a uint32_t ip
-  char ip_str[20];
-  c_memset(ip_str, 0, sizeof(ip_str));
-  if(ipaddr->addr != 0)
-  {
-    c_sprintf(ip_str, IPSTR, IP2STR(&(ipaddr->addr)));
-  }
 
-  lua_rawgeti(gL, LUA_REGISTRYINDEX, nud->cb_dns_found_ref);    // the callback function
-  //lua_rawgeti(gL, LUA_REGISTRYINDEX, nud->self_ref);  // pass the userdata(conn) to callback func in lua
-  lua_pushstring(gL, ip_str);   // the ip para
-*/
+  lua_State *L = lua_getstate();
 
-  // "enhanced"
-
-  lua_rawgeti(gL, LUA_REGISTRYINDEX, nud->cb_dns_found_ref);    // the callback function
-  lua_rawgeti(gL, LUA_REGISTRYINDEX, nud->self_ref);  // pass the userdata(conn) to callback func in lua
+  lua_rawgeti(L, LUA_REGISTRYINDEX, nud->cb_dns_found_ref);    // the callback function
+  lua_rawgeti(L, LUA_REGISTRYINDEX, nud->self_ref);  // pass the userdata(conn) to callback func in lua
 
   if(ipaddr == NULL)
   {
     NODE_DBG( "DNS Fail!\n" );
-    lua_pushnil(gL);
+    lua_pushnil(L);
   }else{
     // ipaddr->addr is a uint32_t ip
     char ip_str[20];
@@ -241,21 +224,21 @@ static void net_dns_found(const char *name, ip_addr_t *ipaddr, void *arg)
     {
       c_sprintf(ip_str, IPSTR, IP2STR(&(ipaddr->addr)));
     }
-    lua_pushstring(gL, ip_str);   // the ip para
+    lua_pushstring(L, ip_str);   // the ip para
   }
   // "enhanced" end
 
-  lua_call(gL, 2, 0);
+  lua_call(L, 2, 0);
 
 end:
   if((pesp_conn->type == ESPCONN_TCP && pesp_conn->proto.tcp->remote_port == 0)
     || (pesp_conn->type == ESPCONN_UDP && pesp_conn->proto.udp->remote_port == 0) ){
-    lua_gc(gL, LUA_GCSTOP, 0);
+    lua_gc(L, LUA_GCSTOP, 0);
     if(nud->self_ref != LUA_NOREF){
-      luaL_unref(gL, LUA_REGISTRYINDEX, nud->self_ref);
+      luaL_unref(L, LUA_REGISTRYINDEX, nud->self_ref);
       nud->self_ref = LUA_NOREF; // unref this, and the net.socket userdata will delete it self
     }
-    lua_gc(gL, LUA_GCRESTART, 0);
+    lua_gc(L, LUA_GCRESTART, 0);
   }
 }
 
@@ -295,25 +278,24 @@ static void net_server_connected(void *arg) // for tcp only
 
   if(tcpserver_cb_connect_ref == LUA_NOREF)
     return;
-  if(!gL)
-    return;
+  lua_State *L = lua_getstate();
 
-  lua_rawgeti(gL, LUA_REGISTRYINDEX, tcpserver_cb_connect_ref);  // get function
+  lua_rawgeti(L, LUA_REGISTRYINDEX, tcpserver_cb_connect_ref);  // get function
   // create a new client object
-  skt = (lnet_userdata *)lua_newuserdata(gL, sizeof(lnet_userdata));
+  skt = (lnet_userdata *)lua_newuserdata(L, sizeof(lnet_userdata));
 
   if(!skt){
     NODE_ERR("can't newudata\n");
-    lua_pop(gL, 1);
+    lua_pop(L, 1);
     return;
   }
   // set its metatable
-  luaL_getmetatable(gL, "net.socket");
-  lua_setmetatable(gL, -2);
+  luaL_getmetatable(L, "net.socket");
+  lua_setmetatable(L, -2);
   // pre-initialize it, in case of errors
   skt->self_ref = LUA_NOREF;
-  lua_pushvalue(gL, -1);  // copy the top of stack
-  skt->self_ref = luaL_ref(gL, LUA_REGISTRYINDEX);    // ref to it self, for module api to find the userdata
+  lua_pushvalue(L, -1);  // copy the top of stack
+  skt->self_ref = luaL_ref(L, LUA_REGISTRYINDEX);    // ref to it self, for module api to find the userdata
   socket[i] = skt->self_ref;  // save to socket array
   socket_num++;
   skt->cb_connect_ref = LUA_NOREF;  // this socket already connected
@@ -337,7 +319,7 @@ static void net_server_connected(void *arg) // for tcp only
   espconn_regist_reconcb(pesp_conn, net_server_reconnected);
 
   // now socket[i] has the client ref, and stack top has the userdata
-  lua_call(gL, 1, 0);  // function(conn)
+  lua_call(L, 1, 0);  // function(conn)
 }
 
 static void net_socket_connected(void *arg)
@@ -358,9 +340,10 @@ static void net_socket_connected(void *arg)
     return;
   if(nud->self_ref == LUA_NOREF)
     return;
-  lua_rawgeti(gL, LUA_REGISTRYINDEX, nud->cb_connect_ref);
-  lua_rawgeti(gL, LUA_REGISTRYINDEX, nud->self_ref);  // pass the userdata(client) to callback func in lua
-  lua_call(gL, 1, 0);
+  lua_State *L = lua_getstate();
+  lua_rawgeti(L, LUA_REGISTRYINDEX, nud->cb_connect_ref);
+  lua_rawgeti(L, LUA_REGISTRYINDEX, nud->self_ref);  // pass the userdata(client) to callback func in lua
+  lua_call(L, 1, 0);
 }
 
 // Lua: s = net.create(type, secure/timeout, function(conn))
@@ -492,8 +475,6 @@ static int net_create( lua_State* L, const char* mt )
     pUdpServer = pesp_conn;
   }
 
-  gL = L;   // global L for net module.
-
   // if call back function is specified, call it with para userdata
   // luaL_checkanyfunction(L, 2);
   if (lua_type(L, stack) == LUA_TFUNCTION || lua_type(L, stack) == LUA_TLIGHTFUNCTION){
@@ -575,12 +556,12 @@ static int net_delete( lua_State* L, const char* mt )
     luaL_unref(L, LUA_REGISTRYINDEX, nud->cb_dns_found_ref);
     nud->cb_dns_found_ref = LUA_NOREF;
   }
-  lua_gc(gL, LUA_GCSTOP, 0);
+  lua_gc(L, LUA_GCSTOP, 0);
   if(LUA_NOREF!=nud->self_ref){
     luaL_unref(L, LUA_REGISTRYINDEX, nud->self_ref);
     nud->self_ref = LUA_NOREF;
   }
-  lua_gc(gL, LUA_GCRESTART, 0);
+  lua_gc(L, LUA_GCRESTART, 0);
   return 0;  
 }
 
@@ -625,19 +606,18 @@ static void socket_dns_found(const char *name, ip_addr_t *ipaddr, void *arg)
   lnet_userdata *nud = (lnet_userdata *)pesp_conn->reverse;
   if(nud == NULL)
     return;
-  if(gL == NULL)
-    return;
+  lua_State *L = lua_getstate();
   if(ipaddr == NULL)
   {
     dns_reconn_count++;
     if( dns_reconn_count >= 5 ){
       NODE_ERR( "DNS Fail!\n" );
-      lua_gc(gL, LUA_GCSTOP, 0);
+      lua_gc(L, LUA_GCSTOP, 0);
       if(nud->self_ref != LUA_NOREF){
-        luaL_unref(gL, LUA_REGISTRYINDEX, nud->self_ref);
+        luaL_unref(L, LUA_REGISTRYINDEX, nud->self_ref);
         nud->self_ref = LUA_NOREF; // unref this, and the net.socket userdata will delete it self
       }
-      lua_gc(gL, LUA_GCRESTART, 0);
+      lua_gc(L, LUA_GCRESTART, 0);
       return;
     }
     NODE_ERR( "DNS retry %d!\n", dns_reconn_count );
@@ -1175,8 +1155,8 @@ static int net_dns_static( lua_State* L )
   lua_pushinteger(L, UDP); // we are going to create a new dummy UDP socket
   lua_call(L,1,1);// after this the stack should have a socket
 
-  lua_rawgeti(gL, LUA_REGISTRYINDEX, rdom);    // load domain back to the stack
-  lua_rawgeti(gL, LUA_REGISTRYINDEX, rfunc);    // load the callback function back to the stack
+  lua_rawgeti(L, LUA_REGISTRYINDEX, rdom);    // load domain back to the stack
+  lua_rawgeti(L, LUA_REGISTRYINDEX, rfunc);    // load the callback function back to the stack
 
   luaL_unref(L, LUA_REGISTRYINDEX, rdom); //free reference
   luaL_unref(L, LUA_REGISTRYINDEX, rfunc); //free reference
diff --git a/app/modules/node.c b/app/modules/node.c
index 39b0feea..18a770e6 100644
--- a/app/modules/node.c
+++ b/app/modules/node.c
@@ -333,7 +333,7 @@ void output_redirect(const char *str) {
   //   return;
   // }
 
-  if (output_redir_ref == LUA_NOREF || !L) {
+  if (output_redir_ref == LUA_NOREF) {
     uart0_sendStr(str);
     return;
   }
diff --git a/app/modules/sntp.c b/app/modules/sntp.c
index 68b78577..14695395 100644
--- a/app/modules/sntp.c
+++ b/app/modules/sntp.c
@@ -204,7 +204,7 @@ static void on_recv (void *arg, struct udp_pcb *pcb, struct pbuf *p, struct ip_a
   (void)port;
   sntp_dbg("sntp: on_recv\n");
 
-  lua_State *L = arg;
+  lua_State *L = lua_getstate();
 
   if (!state || state->pcb != pcb)
   {
diff --git a/app/modules/uart.c b/app/modules/uart.c
index 857d7137..f78b2d9a 100755
--- a/app/modules/uart.c
+++ b/app/modules/uart.c
@@ -8,7 +8,6 @@
 #include "c_string.h"
 #include "rom.h"
 
-static lua_State *gL = NULL;
 static int uart_receive_rf = LUA_NOREF;
 bool run_input = true;
 bool uart_on_data_cb(const char *buf, size_t len){
@@ -16,11 +15,12 @@ bool uart_on_data_cb(const char *buf, size_t len){
     return false;
   if(uart_receive_rf == LUA_NOREF)
     return false;
-  if(!gL)
+  lua_State *L = lua_getstate();
+  if(!L)
     return false;
-  lua_rawgeti(gL, LUA_REGISTRYINDEX, uart_receive_rf);
-  lua_pushlstring(gL, buf, len);
-  lua_call(gL, 1, 0);
+  lua_rawgeti(L, LUA_REGISTRYINDEX, uart_receive_rf);
+  lua_pushlstring(L, buf, len);
+  lua_call(L, 1, 0);
   return !run_input;
 }
 
@@ -75,7 +75,6 @@ static int uart_on( lua_State* L )
     }
     if(!lua_isnil(L, -1)){
       uart_receive_rf = luaL_ref(L, LUA_REGISTRYINDEX);
-      gL = L;
       if(run==0)
         run_input = false;
     } else {