diff --git a/cores/esp8266/core_esp8266_phy.c b/cores/esp8266/core_esp8266_phy.c
index 2391ffa374..67604174e5 100644
--- a/cores/esp8266/core_esp8266_phy.c
+++ b/cores/esp8266/core_esp8266_phy.c
@@ -25,6 +25,8 @@
  #include <stdbool.h>
  #include <string.h>
  #include "c_types.h"
+ #include "ets_sys.h"
+ #include "spi_flash.h"
 
 static const uint8_t ICACHE_FLASH_ATTR phy_init_data[128] =
 {
@@ -228,7 +230,7 @@ static const uint8_t ICACHE_FLASH_ATTR phy_init_data[128] =
     // 3: auto measure frequency offset and correct it,  bbpll is 160M, it only can correct + frequency offset.
     // 5: use 113 byte force_freq_offset to correct frequency offset, bbpll is 168M, it can correct + and - frequency offset.
     // 7: use 113 byte force_freq_offset to correct frequency offset, bbpll is 160M , it only can correct + frequency offset.
-    [112] = 3,
+    [112] = 0,
 
     // force_freq_offset
     // signed, unit is 8kHz
@@ -250,14 +252,20 @@ static const uint8_t ICACHE_FLASH_ATTR phy_init_data[128] =
 #define __get_rf_mode _Z13__get_rf_modev
 #define __run_user_rf_pre_init _Z22__run_user_rf_pre_initv
 
-extern int __real_register_chipv6_phy(uint8_t* init_data);
-extern int __wrap_register_chipv6_phy(uint8_t* init_data)
+static bool spoof_init_data = false;
+
+extern int __real_spi_flash_read(uint32_t addr, uint32_t* dst, size_t size);
+extern int ICACHE_RAM_ATTR __wrap_spi_flash_read(uint32_t addr, uint32_t* dst, size_t size);
+
+extern int ICACHE_RAM_ATTR __wrap_spi_flash_read(uint32_t addr, uint32_t* dst, size_t size)
 {
-    if (init_data != NULL) {
-      memcpy(init_data, phy_init_data, sizeof(phy_init_data));
-      init_data[107] = __get_adc_mode();
+    if (!spoof_init_data || size != 128) {
+        return __real_spi_flash_read(addr, dst, size);
     }
-    return __real_register_chipv6_phy(init_data);
+
+    memcpy(dst, phy_init_data, sizeof(phy_init_data));
+    ((uint8_t*)dst)[107] = __get_adc_mode();
+    return 0;
 }
 
 extern int __get_rf_mode(void)  __attribute__((weak));
@@ -278,10 +286,16 @@ extern void __run_user_rf_pre_init(void)
     return; // default do noting
 }
 
+uint32_t user_rf_cal_sector_set(void)
+{
+    spoof_init_data = true;
+    return flashchip->chip_size/SPI_FLASH_SEC_SIZE - 4;
+}
+
 void user_rf_pre_init()
 {
     // *((volatile uint32_t*) 0x60000710) = 0;
-
+    spoof_init_data = false;
     volatile uint32_t* rtc_reg = (volatile uint32_t*) 0x60001000;
     if((rtc_reg[24] >> 16) > 4) {
         rtc_reg[24] &= 0xFFFF;
@@ -295,3 +309,7 @@ void user_rf_pre_init()
     }
     __run_user_rf_pre_init();
 }
+
+
+void ICACHE_RAM_ATTR user_spi_flash_dio_to_qio_pre_init() {}
+
diff --git a/platform.txt b/platform.txt
index ea8094077a..f8f79de6c9 100644
--- a/platform.txt
+++ b/platform.txt
@@ -31,7 +31,7 @@ compiler.c.flags=-c {compiler.warning_flags} -Os -g -Wpointer-arith -Wno-implici
 compiler.S.cmd=xtensa-lx106-elf-gcc
 compiler.S.flags=-c -g -x assembler-with-cpp -MMD -mlongcalls
 
-compiler.c.elf.flags=-g {compiler.warning_flags} -Os -nostdlib -Wl,--no-check-sections -u call_user_start -u _printf_float -u _scanf_float -Wl,-static "-L{compiler.sdk.path}/lib" "-L{compiler.sdk.path}/ld" "-L{compiler.libc.path}/lib" "-T{build.flash_ld}" -Wl,--gc-sections -Wl,-wrap,system_restart_local -Wl,-wrap,register_chipv6_phy
+compiler.c.elf.flags=-g {compiler.warning_flags} -Os -nostdlib -Wl,--no-check-sections -u call_user_start -u _printf_float -u _scanf_float -Wl,-static "-L{compiler.sdk.path}/lib" "-L{compiler.sdk.path}/ld" "-L{compiler.libc.path}/lib" "-T{build.flash_ld}" -Wl,--gc-sections -Wl,-wrap,system_restart_local -Wl,-wrap,spi_flash_read 
 
 compiler.c.elf.cmd=xtensa-lx106-elf-gcc
 compiler.c.elf.libs=-lhal -lphy -lpp -lnet80211 {build.lwip_lib} -lwpa -lcrypto -lmain -lwps -laxtls -lespnow -lsmartconfig -lmesh -lwpa2 -lstdc++ -lm -lc -lgcc 
diff --git a/tools/sdk/changelog.txt b/tools/sdk/changelog.txt
index 14fb2bc3ae..1766ea6140 100644
--- a/tools/sdk/changelog.txt
+++ b/tools/sdk/changelog.txt
@@ -1,3 +1,30 @@
+ESP8266_NONOS_SDK_V2.0.0_16_07_19 Release Note
+----------------------------------------------
+1. Updated libphy.a to 1055, fixed an issue of large current in Light-sleep.
+2. Updated AT+ to 1.3.0:
+   2.1 Added Light-sleep wakeup command, AT+WAKEUPGPIO;
+   2.2 Fixed abnormal AT+CWDHCPS IP allocation;
+   2.3 Added at_sdio demo under example directory.
+3. Fixed probable system default when calling cur and def interfaces.
+4. Fixed the issue of high current in Deep-sleep mode without disabling SPI first.
+5. Fixed an issue where the SDK would crash when switching from AP to Station mode by calling wifi_set_phy_mode.
+6. Updated secondary boot loader to v1.6:
+   6.1 Supports AT + based on SDIO;
+   6.2 Supports entering testing mode through GPIO.
+7. Added support for MXIC Flash QIO mode.
+8. Fixed exception caused during TCP handshake and retransmission.
+9. Fixed issues in ESP-NOW.
+10. Added ESP-PAIR (Simple-Pair) feature, for APIs please refer to ESP8266 SDK API Guide.
+11. wpa2-enterprise time function derivation and time check disable can be set by users.
+12. Support for PEAP/TTLS in wpa2-enterprise, for APIs please refer to ESP8266 SDK API Guide.
+13. Added mqtt demos under examples directory.
+14. Other issue fixes.
+15. Resolved an issue that RF_Init_data sector may be broken in stress test. Provided a function user_rf_cal_sector_set which has to be added in application by software developer. More details about user_rf_cal_sector_set refer to documentation "2C-ESP8266__SDK__API Guide". (Resolved in ESP8266_NONOS_SDK_V1.5.4.1) 
+16. Fix a potential risk that will cause rf not work after external reset. (Resolved in ESP8266_NONOS_SDK_V1.5.4.1)
+17. Add SDIO AT support. (Resolved in ESP8266_NONOS_SDK_V1.5.4.1)
+18. Fix a potential bug in espconn. (Resolved in ESP8266_NONOS_SDK_V1.5.4.1)
+
+
 ESP8266_NONOS_SDK_V1.5.4_16_05_20 Release Note 
 ----------------------------------------------
 Optimization:
diff --git a/tools/sdk/include/eagle_soc.h b/tools/sdk/include/eagle_soc.h
index 04e033067a..2a77e188b0 100644
--- a/tools/sdk/include/eagle_soc.h
+++ b/tools/sdk/include/eagle_soc.h
@@ -173,6 +173,11 @@
 //RTC reg {{
 #define REG_RTC_BASE  PERIPHS_RTC_BASEADDR
 
+#define RTC_STORE0                              (REG_RTC_BASE + 0x030)
+#define RTC_STORE1                              (REG_RTC_BASE + 0x034)
+#define RTC_STORE2                              (REG_RTC_BASE + 0x038)
+#define RTC_STORE3                              (REG_RTC_BASE + 0x03C)
+
 #define RTC_GPIO_OUT                            (REG_RTC_BASE + 0x068)
 #define RTC_GPIO_ENABLE                         (REG_RTC_BASE + 0x074)
 #define RTC_GPIO_IN_DATA                        (REG_RTC_BASE + 0x08C)
diff --git a/tools/sdk/include/espnow.h b/tools/sdk/include/espnow.h
index 3bb6f83394..bd0ebc42bf 100644
--- a/tools/sdk/include/espnow.h
+++ b/tools/sdk/include/espnow.h
@@ -10,6 +10,7 @@ enum esp_now_role {
 	ESP_NOW_ROLE_IDLE = 0,
 	ESP_NOW_ROLE_CONTROLLER,
 	ESP_NOW_ROLE_SLAVE,
+	ESP_NOW_ROLE_COMBO,
 	ESP_NOW_ROLE_MAX,
 };
 
diff --git a/tools/sdk/include/simple_pair.h b/tools/sdk/include/simple_pair.h
new file mode 100644
index 0000000000..ccab95bced
--- /dev/null
+++ b/tools/sdk/include/simple_pair.h
@@ -0,0 +1,45 @@
+/*
+ *  Copyright (C) 2015 -2018  Espressif System
+ *
+ */
+
+#ifndef __SIMPLE_PAIR_H__
+#define __SIMPLE_PAIR_H__
+
+typedef enum {
+	SP_ST_STA_FINISH = 0,
+	SP_ST_AP_FINISH = 0,
+	SP_ST_AP_RECV_NEG,
+	SP_ST_STA_AP_REFUSE_NEG,
+	/* all following is err */
+	SP_ST_WAIT_TIMEOUT,
+	SP_ST_SEND_ERROR,
+	SP_ST_KEY_INSTALL_ERR,
+	SP_ST_KEY_OVERLAP_ERR,  //means the same macaddr has two different keys 
+	SP_ST_OP_ERROR,
+	SP_ST_UNKNOWN_ERROR,
+	SP_ST_MAX,
+} SP_ST_t;
+
+
+typedef void (*simple_pair_status_cb_t)(u8 *sa, u8 status);
+
+int register_simple_pair_status_cb(simple_pair_status_cb_t cb);
+void unregister_simple_pair_status_cb(void);
+
+int simple_pair_init(void);
+void simple_pair_deinit(void);
+
+int simple_pair_state_reset(void);
+int simple_pair_ap_enter_announce_mode(void);
+int simple_pair_sta_enter_scan_mode(void);
+
+int simple_pair_sta_start_negotiate(void);
+int simple_pair_ap_start_negotiate(void);
+int simple_pair_ap_refuse_negotiate(void);
+
+int simple_pair_set_peer_ref(u8 *peer_mac, u8 *tmp_key, u8 *ex_key);
+int simple_pair_get_peer_ref(u8 *peer_mac, u8 *tmp_key, u8 *ex_key);
+
+
+#endif /* __SIMPLE_PAIR_H__ */
diff --git a/tools/sdk/include/user_interface.h b/tools/sdk/include/user_interface.h
index f9195829c9..1dcf7c2f46 100644
--- a/tools/sdk/include/user_interface.h
+++ b/tools/sdk/include/user_interface.h
@@ -16,6 +16,7 @@
 #include "queue.h"
 #include "user_config.h"
 #include "spi_flash.h"
+#include "gpio.h"
 
 #ifndef MAC2STR
 #define MAC2STR(a) (a)[0], (a)[1], (a)[2], (a)[3], (a)[4], (a)[5]
@@ -178,6 +179,7 @@ typedef struct bss_info {
     sint16 freq_offset;
     sint16 freqcal_val;
 	uint8 *esp_mesh_ie;
+	uint8 simple_pair;
 } bss_info_t;
 
 typedef struct _scaninfo {
@@ -606,4 +608,7 @@ bool wifi_set_user_ie(bool enable, uint8 *m_oui, uint8 type, uint8 *user_ie, uin
 int wifi_register_user_ie_manufacturer_recv_cb(user_ie_manufacturer_recv_cb_t cb);
 void wifi_unregister_user_ie_manufacturer_recv_cb(void);
 
+void wifi_enable_gpio_wakeup(uint32 i, GPIO_INT_TYPE intr_status);
+void wifi_disable_gpio_wakeup(void);
+
 #endif
diff --git a/tools/sdk/include/wpa2_enterprise.h b/tools/sdk/include/wpa2_enterprise.h
new file mode 100644
index 0000000000..f83b8db7a5
--- /dev/null
+++ b/tools/sdk/include/wpa2_enterprise.h
@@ -0,0 +1,38 @@
+#ifndef __WPA2_ENTERPRISE_H__
+#define __WPA2_ENTERPRISE_H__
+
+typedef long os_time_t;
+
+struct os_time {
+	os_time_t sec;
+	os_time_t usec;
+};
+
+typedef int (* get_time_func_t)(struct os_time *t);
+
+int  wifi_station_set_wpa2_enterprise_auth(int enable);
+
+int  wifi_station_set_enterprise_cert_key(u8 *client_cert, int client_cert_len,
+			u8 *private_key, int private_key_len,
+			u8 *private_key_passwd, int private_key_passwd_len);
+void  wifi_station_clear_enterprise_cert_key(void);
+
+int  wifi_station_set_enterprise_ca_cert(u8 *ca_cert, int ca_cert_len);
+void  wifi_station_clear_enterprise_ca_cert(void);
+
+int  wifi_station_set_enterprise_username(u8 *username, int len);
+void  wifi_station_clear_enterprise_username(void);
+
+int  wifi_station_set_enterprise_password(u8 *password, int len);
+void  wifi_station_clear_enterprise_password(void);
+
+int  wifi_station_set_enterprise_new_password(u8 *new_password, int len);
+void  wifi_station_clear_enterprise_new_password(void);
+
+void  wifi_station_set_enterprise_disable_time_check(bool disable);
+bool  wifi_station_get_enterprise_disable_time_check(void);
+
+void  wpa2_enterprise_set_user_get_time(get_time_func_t cb);
+
+
+#endif /* __WPA2_ENTERPRISE_H__ */
diff --git a/tools/sdk/ld/eagle.app.v6.common.ld b/tools/sdk/ld/eagle.app.v6.common.ld
index 2ed1b887b6..a2e082c4a9 100644
--- a/tools/sdk/ld/eagle.app.v6.common.ld
+++ b/tools/sdk/ld/eagle.app.v6.common.ld
@@ -163,6 +163,8 @@ SECTIONS
     *libgcc.a:_udivdi3.o(.literal .text)
     *libsmartconfig.a:(.literal .text .literal.* .text.*)
     *libstdc++.a:(.literal .text .literal.* .text.*)
+    *liblwip_gcc.a:(.literal .text .literal.* .text.*)
+    *liblwip_src.a:(.literal .text .literal.* .text.*)
     *(.irom0.literal .irom.literal .irom.text.literal .irom0.text .irom.text .irom.text.*)
     _irom0_text_end = ABSOLUTE(.);
     _flash_code_end = ABSOLUTE(.);
diff --git a/tools/sdk/ld/eagle.rom.addr.v6.ld b/tools/sdk/ld/eagle.rom.addr.v6.ld
index 19576cb73d..9269fa2de5 100644
--- a/tools/sdk/ld/eagle.rom.addr.v6.ld
+++ b/tools/sdk/ld/eagle.rom.addr.v6.ld
@@ -20,6 +20,7 @@ PROVIDE ( SPI_read_status = 0x400043c8 );
 PROVIDE ( SPI_write_status = 0x40004400 );
 PROVIDE ( SPI_write_enable = 0x4000443c );
 PROVIDE ( Wait_SPI_Idle = 0x4000448c );
+PROVIDE ( Enable_QMode = 0x400044c0 );
 PROVIDE ( SPIEraseArea = 0x40004b44 );
 PROVIDE ( SPIEraseBlock = 0x400049b4 );
 PROVIDE ( SPIEraseChip = 0x40004984 );
diff --git a/tools/sdk/lib/libat.a b/tools/sdk/lib/libat.a
index 36fed2efb1..7dbb6ae146 100644
Binary files a/tools/sdk/lib/libat.a and b/tools/sdk/lib/libat.a differ
diff --git a/tools/sdk/lib/libcrypto.a b/tools/sdk/lib/libcrypto.a
index 17dcc8ab40..56245a3d58 100644
Binary files a/tools/sdk/lib/libcrypto.a and b/tools/sdk/lib/libcrypto.a differ
diff --git a/tools/sdk/lib/libdriver.a b/tools/sdk/lib/libdriver.a
new file mode 100644
index 0000000000..68d314c326
Binary files /dev/null and b/tools/sdk/lib/libdriver.a differ
diff --git a/tools/sdk/lib/libespnow.a b/tools/sdk/lib/libespnow.a
index 964236e83d..ac9b407fae 100644
Binary files a/tools/sdk/lib/libespnow.a and b/tools/sdk/lib/libespnow.a differ
diff --git a/tools/sdk/lib/libgcc.a b/tools/sdk/lib/libgcc.a
new file mode 100644
index 0000000000..beb9274848
Binary files /dev/null and b/tools/sdk/lib/libgcc.a differ
diff --git a/tools/sdk/lib/libjson.a b/tools/sdk/lib/libjson.a
index 4f4eefc8b3..f85ce36b4c 100644
Binary files a/tools/sdk/lib/libjson.a and b/tools/sdk/lib/libjson.a differ
diff --git a/tools/sdk/lib/liblwip.a b/tools/sdk/lib/liblwip.a
index 2e6ff96bda..829db331b5 100644
Binary files a/tools/sdk/lib/liblwip.a and b/tools/sdk/lib/liblwip.a differ
diff --git a/tools/sdk/lib/liblwip_536.a b/tools/sdk/lib/liblwip_536.a
new file mode 100644
index 0000000000..19b12d93f4
Binary files /dev/null and b/tools/sdk/lib/liblwip_536.a differ
diff --git a/tools/sdk/lib/liblwip_gcc.a b/tools/sdk/lib/liblwip_gcc.a
index f1cfed0d34..4758c769a3 100644
Binary files a/tools/sdk/lib/liblwip_gcc.a and b/tools/sdk/lib/liblwip_gcc.a differ
diff --git a/tools/sdk/lib/libmain.a b/tools/sdk/lib/libmain.a
index d9b9ed6756..fdc93e024b 100644
Binary files a/tools/sdk/lib/libmain.a and b/tools/sdk/lib/libmain.a differ
diff --git a/tools/sdk/lib/libmesh.a b/tools/sdk/lib/libmesh.a
index 8c9b237f71..277ece582a 100644
Binary files a/tools/sdk/lib/libmesh.a and b/tools/sdk/lib/libmesh.a differ
diff --git a/tools/sdk/lib/libnet80211.a b/tools/sdk/lib/libnet80211.a
index 34cac64a86..5081dd3671 100644
Binary files a/tools/sdk/lib/libnet80211.a and b/tools/sdk/lib/libnet80211.a differ
diff --git a/tools/sdk/lib/libphy.a b/tools/sdk/lib/libphy.a
index 273baae695..05ab062970 100644
Binary files a/tools/sdk/lib/libphy.a and b/tools/sdk/lib/libphy.a differ
diff --git a/tools/sdk/lib/libpp.a b/tools/sdk/lib/libpp.a
index 128628e852..bb93cbebbc 100644
Binary files a/tools/sdk/lib/libpp.a and b/tools/sdk/lib/libpp.a differ
diff --git a/tools/sdk/lib/libsmartconfig.a b/tools/sdk/lib/libsmartconfig.a
index c0d4e27bd6..b85460ccea 100644
Binary files a/tools/sdk/lib/libsmartconfig.a and b/tools/sdk/lib/libsmartconfig.a differ
diff --git a/tools/sdk/lib/libssl.a b/tools/sdk/lib/libssl.a
index 3565e03c24..4b6beab413 100644
Binary files a/tools/sdk/lib/libssl.a and b/tools/sdk/lib/libssl.a differ
diff --git a/tools/sdk/lib/libupgrade.a b/tools/sdk/lib/libupgrade.a
index 4ff86489dc..fa6560bdb9 100644
Binary files a/tools/sdk/lib/libupgrade.a and b/tools/sdk/lib/libupgrade.a differ
diff --git a/tools/sdk/lib/libwpa.a b/tools/sdk/lib/libwpa.a
index 78305ff2ab..18d966d3b5 100644
Binary files a/tools/sdk/lib/libwpa.a and b/tools/sdk/lib/libwpa.a differ
diff --git a/tools/sdk/lib/libwpa2.a b/tools/sdk/lib/libwpa2.a
index e3ef9db225..22eb333793 100644
Binary files a/tools/sdk/lib/libwpa2.a and b/tools/sdk/lib/libwpa2.a differ
diff --git a/tools/sdk/lib/libwps.a b/tools/sdk/lib/libwps.a
index 184fb4c0c4..a1c00c09fa 100644
Binary files a/tools/sdk/lib/libwps.a and b/tools/sdk/lib/libwps.a differ
diff --git a/tools/sdk/lwip/include/arch/cc.h b/tools/sdk/lwip/include/arch/cc.h
index ff03b30709..735e700af5 100644
--- a/tools/sdk/lwip/include/arch/cc.h
+++ b/tools/sdk/lwip/include/arch/cc.h
@@ -40,6 +40,9 @@
 #include "osapi.h"
 #define EFAULT 14
 
+#undef ICACHE_FLASH_ATTR
+#define ICACHE_FLASH_ATTR
+
 //#define LWIP_PROVIDE_ERRNO
 
 #if (1)
diff --git a/tools/sdk/lwip/include/lwip/app/espconn.h b/tools/sdk/lwip/include/lwip/app/espconn.h
index 9738b5e221..5167ce1fc5 100644
--- a/tools/sdk/lwip/include/lwip/app/espconn.h
+++ b/tools/sdk/lwip/include/lwip/app/espconn.h
@@ -3,6 +3,7 @@
 
 #include "lwip/dns.h"
 #include "os_type.h"
+#include "lwip/app/espconn_buf.h"
 
 #if 0
 #define espconn_printf(fmt, args...) os_printf(fmt,## args)
@@ -32,6 +33,8 @@ typedef void (* espconn_reconnect_callback)(void *arg, sint8 err);
 #define ESPCONN_ARG        -12   /* Illegal argument.        */
 #define ESPCONN_IF		   -14	 /* Low_level error			 */
 #define ESPCONN_ISCONN     -15   /* Already connected.       */
+#define ESPCONN_TIME	   -16	 /* Sync Time error			 */
+#define ESPCONN_NODATA	   -17	 /* No data can be read	     */
 
 #define ESPCONN_HANDSHAKE  -28   /* ssl handshake failed	 */
 #define ESPCONN_RESP_TIMEOUT -29 /* ssl handshake no response*/
@@ -186,6 +189,8 @@ typedef struct _espconn_msg{
 //***********Code for WIFI_BLOCK from upper**************
 	uint8 recv_hold_flag;
 	uint16 recv_holded_buf_Len;
+//*******************************************************
+	ringbuf *readbuf;
 }espconn_msg;
 
 #ifndef _MDNS_INFO
diff --git a/tools/sdk/lwip/include/lwip/app/espconn_buf.h b/tools/sdk/lwip/include/lwip/app/espconn_buf.h
new file mode 100644
index 0000000000..8bdfaa12ab
--- /dev/null
+++ b/tools/sdk/lwip/include/lwip/app/espconn_buf.h
@@ -0,0 +1,60 @@
+/*
+ * ringbuf.h
+ *
+ *  Created on: Apr 22, 2016
+ *      Author: liuhan
+ */
+
+#ifndef _ESPCONN_BUF_H_
+#define _ESPCONN_BUF_H_
+
+/*
+ * ringbuffer.c
+ *
+ *  Created on: Apr 22, 2016
+ *      Author: liuhan
+ */
+#include "c_types.h"
+
+#include "ets_sys.h"
+#include "os_type.h"
+
+typedef struct ringbuf_t {
+	uint8_t *buf;
+	uint8_t *head, *tail;
+	size_t size;
+} ringbuf, *ringbuf_t;
+
+ringbuf_t ringbuf_new(size_t capacity);
+
+size_t ringbuf_buffer_size(const struct ringbuf_t *rb);
+
+void ringbuf_reset(ringbuf_t rb);
+
+void ringbuf_free(ringbuf_t *rb);
+
+size_t ringbuf_capacity(const struct ringbuf_t *rb);
+
+size_t ringbuf_bytes_free(const struct ringbuf_t *rb);
+
+size_t ringbuf_bytes_used(const struct ringbuf_t *rb);
+
+int ringbuf_is_full(const struct ringbuf_t *rb);
+
+int ringbuf_is_empty(const struct ringbuf_t *rb);
+
+const void* ringbuf_tail(const struct ringbuf_t *rb);
+
+const void* ringbuf_head(const struct ringbuf_t *rb);
+
+static uint8_t *ringbuf_nextp(ringbuf_t rb, const uint8_t *p);
+
+size_t ringbuf_findchr(const struct ringbuf_t *rb, int c, size_t offset);
+
+size_t ringbuf_memset(ringbuf_t dst, int c, size_t len);
+
+void *ringbuf_memcpy_into(ringbuf_t dst, const void *src, size_t count);
+
+void *ringbuf_memcpy_from(void *dst, ringbuf_t src, size_t count);
+
+#endif /* RINGBUF_H_ */
diff --git a/tools/sdk/lwip/include/lwip/app/time.h b/tools/sdk/lwip/include/lwip/app/time.h
new file mode 100644
index 0000000000..189d7d1f0d
--- /dev/null
+++ b/tools/sdk/lwip/include/lwip/app/time.h
@@ -0,0 +1,53 @@
+/*
+ * time.h
+ *
+ *  Created on: May 31, 2016
+ *      Author: liuhan
+ */
+
+#ifndef TIME_H_
+#define TIME_H_
+#include "osapi.h"
+#include "os_type.h"
+#include "lwip/sntp.h"
+
+struct timeval {
+  unsigned long  tv_sec;         /* seconds */
+  unsigned long  tv_usec;        /* and microseconds */
+};
+
+/***************************RTC TIME OPTION***************************************/
+// daylight settings
+// Base calculated with value obtained from NTP server (64 bits)
+#define sntp_base   (*((uint64_t*)RTC_STORE0))
+// Timer value when base was obtained
+#define TIM_REF_SET(value) WRITE_PERI_REG(RTC_STORE2, value)
+#define TIM_REF_GET()      READ_PERI_REG(RTC_STORE2)
+
+// Setters and getters for CAL, TZ and DST.
+#define RTC_CAL_SET(val)    do {uint32 value = READ_PERI_REG(RTC_STORE3);\
+    value |= ((val) & 0x0000FFFF);\
+    WRITE_PERI_REG(RTC_STORE3, value);\
+    }while(0)
+#define RTC_DST_SET(val)    do {uint32 value = READ_PERI_REG(RTC_STORE3);\
+    value |= (((val)<<16) & 0x00010000);\
+    WRITE_PERI_REG(RTC_STORE3, value);\
+    }while(0)
+#define RTC_TZ_SET(val)     do {uint32 value = READ_PERI_REG(RTC_STORE3);\
+    value |= (((val)<<24) & 0xFF000000);\
+    WRITE_PERI_REG(RTC_STORE3, value);\
+    }while(0)
+
+#define RTC_CAL_GET()       (READ_PERI_REG(RTC_STORE3) & 0x0000FFFF)
+#define RTC_DST_GET()       ((READ_PERI_REG(RTC_STORE3) & 0x00010000)>>16)
+#define RTC_TZ_GET()        ((((int)READ_PERI_REG(RTC_STORE3)) & ((int)0xFF000000))>>24)
+void system_update_rtc(time_t t, uint32_t us);
+time_t sntp_get_rtc_time(sint32_t *us);
+
+int  gettimeofday(struct timeval* t, void* timezone);
+void updateTime(uint32 ms);
+bool configTime(int timezone, int daylightOffset, char *server1, char *server2, char *server3, bool enable);
+time_t time(time_t *t);
+unsigned long millis(void);
+unsigned long micros(void);
+#endif /* TIME_H_ */
diff --git a/tools/sdk/lwip/include/lwip/sntp.h b/tools/sdk/lwip/include/lwip/sntp.h
index 14e802e15a..e0d523be1e 100644
--- a/tools/sdk/lwip/include/lwip/sntp.h
+++ b/tools/sdk/lwip/include/lwip/sntp.h
@@ -8,6 +8,8 @@
 extern "C" {
 #endif
 
+typedef long     time_t;
+
 /** The maximum number of SNTP servers that can be set */
 #ifndef SNTP_MAX_SERVERS
 #define SNTP_MAX_SERVERS           3
@@ -24,6 +26,8 @@ extern "C" {
 #define SNTP_SERVER_DNS            1
 #endif
 
+bool sntp_get_timetype(void);
+void sntp_set_receive_time_size(void);
 /** One server address/name can be defined as default if SNTP_SERVER_DNS == 1:
  * #define SNTP_SERVER_ADDRESS "pool.ntp.org"
  */
diff --git a/tools/sdk/lwip/src/app/dhcpserver.c b/tools/sdk/lwip/src/app/dhcpserver.c
index 916b46398b..60736b0cae 100644
--- a/tools/sdk/lwip/src/app/dhcpserver.c
+++ b/tools/sdk/lwip/src/app/dhcpserver.c
@@ -92,10 +92,12 @@ void ICACHE_FLASH_ATTR node_remove_from_list(list_node **phead, list_node* pdele
     } else {
         if (plist == pdelete){
             *phead = plist->pnext;
+            pdelete->pnext = NULL;
         } else {
             while (plist != NULL) {
                 if (plist->pnext == pdelete){
                     plist->pnext = pdelete->pnext;
+                    pdelete->pnext = NULL;
                 }
                 plist = plist->pnext;
             }
@@ -269,7 +271,10 @@ static void ICACHE_FLASH_ATTR create_msg(struct dhcps_msg *m)
         os_memset((char *) m->file, 0, sizeof(m->file));
 
         os_memset((char *) m->options, 0, sizeof(m->options));
-        os_memcpy((char *) m->options, &magic_cookie, sizeof(magic_cookie));
+
+//For xiaomi crash bug
+		uint32 magic_cookie1 = magic_cookie;
+        os_memcpy((char *) m->options, &magic_cookie1, sizeof(magic_cookie1));
 }
 ///////////////////////////////////////////////////////////////////////////////////
 /*
@@ -760,11 +765,18 @@ void ICACHE_FLASH_ATTR dhcps_stop(void)
     //udp_remove(pcb_dhcps);
     list_node *pnode = NULL;
     list_node *pback_node = NULL;
+    struct dhcps_pool* dhcp_node = NULL;
+    struct ip_addr ip_zero;
+
+    os_memset(&ip_zero,0x0,sizeof(ip_zero));
     pnode = plist;
     while (pnode != NULL) {
         pback_node = pnode;
         pnode = pback_node->pnext;
         node_remove_from_list(&plist, pback_node);
+        dhcp_node = (struct dhcps_pool*)pback_node->pnode;
+        //wifi_softap_dhcps_client_leave(dhcp_node->mac,&dhcp_node->ip,TRUE); // force to delete
+        wifi_softap_set_station_info(dhcp_node->mac, &ip_zero);
         os_free(pback_node->pnode);
         pback_node->pnode = NULL;
         os_free(pback_node);
@@ -1077,10 +1089,10 @@ uint32 ICACHE_FLASH_ATTR wifi_softap_dhcps_client_update(u8 *bssid, struct ip_ad
                 return IPADDR_ANY;
             }
         } else {
-            if (start_ip == end_ip) {
+            if (start_ip > end_ip) {
                 return IPADDR_ANY;
             }
-            start_ip = htonl((ntohl(start_ip) + 1));
+            //start_ip = htonl((ntohl(start_ip) + 1));
             flag = TRUE;
         }
     }
@@ -1096,6 +1108,8 @@ uint32 ICACHE_FLASH_ATTR wifi_softap_dhcps_client_update(u8 *bssid, struct ip_ad
 
                 // mac exists and ip exists in other node,delete mac
                 node_remove_from_list(&plist,pmac_node);
+                os_free(pmac_node->pnode);
+                pmac_node->pnode = NULL;
                 os_free(pmac_node);
                 pmac_node = pip_node;
                 os_memcpy(pdhcps_pool->mac, bssid, sizeof(pdhcps_pool->mac));
@@ -1144,6 +1158,10 @@ uint32 ICACHE_FLASH_ATTR wifi_softap_dhcps_client_update(u8 *bssid, struct ip_ad
                 os_free(pdhcps_pool);
                 return IPADDR_ANY;
             }
+            if (pdhcps_pool->ip.addr > end_ip) {
+                os_free(pdhcps_pool);
+                return IPADDR_ANY;
+            }
             os_memcpy(pdhcps_pool->mac, bssid, sizeof(pdhcps_pool->mac));
             pdhcps_pool->lease_timer = DHCPS_LEASE_TIMER;
             pdhcps_pool->type = type;
diff --git a/tools/sdk/lwip/src/app/espconn.c b/tools/sdk/lwip/src/app/espconn.c
index 8d82e4cd68..93ce6fa4c7 100644
--- a/tools/sdk/lwip/src/app/espconn.c
+++ b/tools/sdk/lwip/src/app/espconn.c
@@ -35,6 +35,8 @@ remot_info premot[linkMax];
 
 struct espconn_packet pktinfo[2];
 
+void espconn_init(void);
+
 static uint8 espconn_tcp_get_buf_count(espconn_buf *pesp_buf);
 /******************************************************************************
  * FunctionName : espconn_copy_partial
@@ -266,6 +268,8 @@ espconn_connect(struct espconn *espconn)
 	espconn_msg *plist = NULL;
 	remot_info *pinfo = NULL;
 
+	volatile int tmp = (int) espconn_init;
+
     if (espconn == NULL) {
         return ESPCONN_ARG;
     } else if (espconn ->type != ESPCONN_TCP)
@@ -336,6 +340,8 @@ espconn_create(struct espconn *espconn)
 	sint8 value = ESPCONN_OK;
 	espconn_msg *plist = NULL;
 
+	volatile int tmp = (int) espconn_init;
+
 	if (espconn == NULL) {
 		return ESPCONN_ARG;
 	} else if (espconn ->type != ESPCONN_UDP){
@@ -436,6 +442,39 @@ espconn_sent(struct espconn *espconn, uint8 *psent, uint16 length)
     return ESPCONN_ARG;
 }
 
+sint16 ICACHE_FLASH_ATTR espconn_recv(struct espconn *espconn, void *mem, size_t len)
+{
+	espconn_msg *pnode = NULL;
+	bool value = false;
+	int bytes_used = 0;
+	if (espconn == NULL || mem == NULL || len == 0)
+		return ESPCONN_ARG;
+
+	/*Find the node depend on the espconn message*/
+	value = espconn_find_connection(espconn, &pnode);
+	if (value && espconn->type == ESPCONN_TCP){
+		if (pnode->readbuf != NULL){
+			bytes_used = ringbuf_bytes_used(pnode->readbuf);
+			if (bytes_used != 0) {
+				if (len > bytes_used) {
+					len = bytes_used;
+				}
+				ringbuf_memcpy_from(mem, pnode->readbuf, len);
+				espconn_recv_unhold(pnode->pespconn);
+				return len;
+			} else {
+				return ESPCONN_OK;
+			}
+		} else{
+			return ESPCONN_OK;
+		}
+	} else{
+		return ESPCONN_ARG;
+	}
+
+	return ESPCONN_ARG;
+}
+
 /******************************************************************************
  * FunctionName : espconn_sendto
  * Description  : send data for UDP
@@ -877,6 +916,8 @@ espconn_accept(struct espconn *espconn)
 	sint8 value = ESPCONN_OK;
 	espconn_msg *plist = NULL;
 
+	volatile int tmp = (int) espconn_init;
+
     if (espconn == NULL) {
         return ESPCONN_ARG;
     } else if (espconn ->type != ESPCONN_TCP)
diff --git a/tools/sdk/lwip/src/app/espconn_buf.c b/tools/sdk/lwip/src/app/espconn_buf.c
new file mode 100644
index 0000000000..f91d1d23ea
--- /dev/null
+++ b/tools/sdk/lwip/src/app/espconn_buf.c
@@ -0,0 +1,205 @@
+/*
+ * espconn_buf.c
+ *
+ *  Created on: May 25, 2016
+ *      Author: liuhan
+ */
+
+#include "lwip/memp.h"
+#include "lwip/def.h"
+#include "ets_sys.h"
+#include "os_type.h"
+#include "lwip/app/espconn_buf.h"
+
+
+#ifdef MEMLEAK_DEBUG
+static const char mem_debug_file[] ICACHE_RODATA_ATTR = __FILE__;
+#endif
+
+#if (!defined(lwIP_unlikely))
+#define lwIP_unlikely(Expression) !!(Expression)
+#endif
+
+#define lwIP_ASSERT(Expression)	do{if(!(Expression)) {os_printf("%s %d\n", __func__, __LINE__);return;}}while(0)
+
+ringbuf_t ringbuf_new(size_t capacity)
+{
+	ringbuf_t rb = (ringbuf_t)os_zalloc(sizeof(struct ringbuf_t));
+	if (rb){
+		rb->size = capacity + 1;
+		rb->buf = (uint8*)os_zalloc(rb->size);
+		if (rb->buf){
+			ringbuf_reset(rb);
+		}else{
+			os_free(rb);
+			return NULL;
+		}
+	}
+	return rb;
+}
+
+size_t ringbuf_buffer_size(const struct ringbuf_t *rb)
+{
+	return rb->size;
+}
+
+void ringbuf_reset(ringbuf_t rb)
+{
+	rb ->head = rb->tail = rb->buf;
+}
+
+void ringbuf_free(ringbuf_t *rb)
+{
+	lwIP_ASSERT(rb && *rb);
+	os_free((*rb)->buf);
+	os_free(*rb);
+	*rb = NULL;
+}
+
+size_t ringbuf_capacity(const struct ringbuf_t *rb)
+{
+	return ringbuf_buffer_size(rb) - 1;
+}
+
+static const uint8_t* ringbuf_end(const struct ringbuf_t *rb)
+{
+	return rb->buf + ringbuf_buffer_size(rb);
+}
+
+size_t ringbuf_bytes_free(const struct ringbuf_t *rb)
+{
+	if (rb->head >= rb->tail){
+		return ringbuf_capacity(rb) - (rb->head - rb->tail);
+	}else{
+		return rb->tail - rb->head -1;
+	}
+}
+
+size_t ringbuf_bytes_used(const struct ringbuf_t *rb)
+{
+	return ringbuf_capacity(rb) - ringbuf_bytes_free(rb);
+}
+
+int ringbuf_is_full(const struct ringbuf_t *rb)
+{
+	return ringbuf_bytes_free(rb) == 0;
+}
+
+int ringbuf_is_empty(const struct ringbuf_t *rb)
+{
+	return ringbuf_bytes_free(rb) == ringbuf_capacity(rb);
+}
+
+const void* ringbuf_tail(const struct ringbuf_t *rb)
+{
+	return rb->tail;
+}
+const void* ringbuf_head(const struct ringbuf_t *rb)
+{
+	return rb->head;
+}
+
+static uint8_t *ringbuf_nextp(ringbuf_t rb, const uint8_t *p)
+{
+	lwIP_ASSERT((p >= rb->buf) && (p < ringbuf_end(rb)));
+	return rb->buf + ((++p -rb->buf) % ringbuf_buffer_size(rb));
+}
+
+size_t ringbuf_findchr(const struct ringbuf_t *rb, int c, size_t offset)
+{
+	const uint8_t *bufend = ringbuf_end(rb);
+	size_t bytes_used = ringbuf_bytes_used(rb);
+	if (offset >= bytes_used)
+		return bytes_used;
+
+	const uint8_t *start = rb ->buf + (((rb->tail - rb->buf) + offset) % ringbuf_buffer_size(rb));
+	lwIP_ASSERT(bufend > start);
+	size_t n = LWIP_MIN(bufend - start, bytes_used - offset);
+	const uint8_t *found = (const uint8_t *)memchr(start, c, n);
+	if (found)
+		return offset + (found - start);
+	else
+		return ringbuf_findchr(rb, c, offset + n);
+}
+
+size_t ringbuf_memset(ringbuf_t dst, int c, size_t len)
+{
+	const uint8_t *bufend = ringbuf_end(dst);
+	size_t nwritten = 0;
+	size_t count = LWIP_MIN(len, ringbuf_buffer_size(dst));
+	int overflow = count > ringbuf_bytes_free(dst);
+
+	while (nwritten != count){
+
+		lwIP_ASSERT(bufend > dst->head);
+		size_t n = LWIP_MIN(bufend - dst->head, count - nwritten);
+		os_memset(dst->head, c, n);
+		dst->head += n;
+		nwritten += n;
+
+		if (dst->head == bufend)
+			dst->head = dst->buf;
+	}
+
+	if (overflow){
+		dst->tail = ringbuf_nextp(dst, dst->head);
+		lwIP_ASSERT(ringbuf_is_full(dst));
+	}
+
+	return nwritten;
+}
+
+void *ringbuf_memcpy_into(ringbuf_t dst,const void *src, size_t count)
+{
+	const uint8_t *u8src = src;
+	const uint8_t *bufend = ringbuf_end(dst);
+	int overflow = count > ringbuf_bytes_free(dst);
+	size_t nread = 0;
+
+	while (nread != count){
+		lwIP_ASSERT(bufend > dst->head);
+		size_t n = LWIP_MIN(bufend - dst->head, count - nread);
+		os_memcpy(dst->head, u8src + nread, n);
+		dst->head += n;
+		nread += n;
+
+		if (dst->head == bufend)
+			dst->head = dst->buf;
+	}
+
+	if (overflow) {
+		dst->tail = ringbuf_nextp(dst, dst->head);
+		lwIP_ASSERT(ringbuf_is_full(dst));
+	}
+
+	return dst->head;
+}
+
+void *ringbuf_memcpy_from(void *dst,ringbuf_t src, size_t count)
+{
+	size_t bytes_used = ringbuf_bytes_used(src);
+
+	if (count > bytes_used)
+		return NULL;
+
+	const uint8_t *u8dst = dst;
+	const uint8_t *bufend = ringbuf_end(src);
+	size_t nwritten = 0;
+
+	while (nwritten != count){
+		lwIP_ASSERT(bufend > src->tail);
+		size_t n = LWIP_MIN(bufend - src->tail, count - nwritten);
+		os_memcpy((uint8_t*)u8dst + nwritten, src->tail, n);
+		src->tail += n;
+		nwritten += n;
+
+		if (src->tail == bufend)
+			src->tail = src->buf;
+	}
+
+	lwIP_ASSERT(count + ringbuf_bytes_used(src) == bytes_used);
+	return src->tail;
+}
+
+
+
diff --git a/tools/sdk/lwip/src/app/espconn_tcp.c b/tools/sdk/lwip/src/app/espconn_tcp.c
index 9be0ac453b..69c86c228e 100644
--- a/tools/sdk/lwip/src/app/espconn_tcp.c
+++ b/tools/sdk/lwip/src/app/espconn_tcp.c
@@ -239,6 +239,10 @@ void ICACHE_FLASH_ATTR espconn_tcp_memp_free(espconn_msg *pmemp)
 		os_free(pmemp->pespconn);
 		pmemp->pespconn = NULL;
 	}
+
+	if (pmemp->readbuf != NULL){
+		ringbuf_free(&pmemp->readbuf);
+	}
 	os_free(pmemp);
 	pmemp = NULL;
 }
@@ -397,34 +401,46 @@ espconn_tcp_disconnect_successful(void *arg)
 static void ICACHE_FLASH_ATTR
 espconn_Task(os_event_t *events)
 {
+	espconn_msg *plist = NULL;
+	bool active_flag = false;
 	espconn_msg *task_msg = NULL;
 	struct espconn *pespconn = NULL;
 
 	task_msg = (espconn_msg *) events->par;
-	switch (events->sig) {
-		case SIG_ESPCONN_WRITE: {
-			pespconn = task_msg->pespconn;
-			if (pespconn == NULL) {
-				return;
-			}
+	/*find the active connection node*/
+	for (plist = plink_active; plist != NULL; plist = plist->pnext){
+		if (task_msg == plist) {
+			active_flag = true;
+			break;
+		}
+	}
+
+	if (active_flag){
+		switch (events->sig) {
+			case SIG_ESPCONN_WRITE: {
+				pespconn = task_msg->pespconn;
+				if (pespconn == NULL) {
+					return;
+				}
 
-			if (pespconn->proto.tcp->write_finish_fn != NULL) {
-				pespconn->proto.tcp->write_finish_fn(pespconn);
+				if (pespconn->proto.tcp->write_finish_fn != NULL) {
+					pespconn->proto.tcp->write_finish_fn(pespconn);
+				}
 			}
+				break;
+			case SIG_ESPCONN_ERRER:
+				/*remove the node from the client's active connection list*/
+				espconn_list_delete(&plink_active, task_msg);
+				espconn_tcp_reconnect(task_msg);
+				break;
+			case SIG_ESPCONN_CLOSE:
+				/*remove the node from the client's active connection list*/
+				espconn_list_delete(&plink_active, task_msg);
+				espconn_tcp_disconnect_successful(task_msg);
+				break;
+			default:
+				break;
 		}
-			break;
-		case SIG_ESPCONN_ERRER:
-			/*remove the node from the client's active connection list*/
-			espconn_list_delete(&plink_active, task_msg);
-			espconn_tcp_reconnect(task_msg);
-			break;
-		case SIG_ESPCONN_CLOSE:
-			/*remove the node from the client's active connection list*/
-			espconn_list_delete(&plink_active, task_msg);
-			espconn_tcp_disconnect_successful(task_msg);
-			break;
-		default:
-			break;
 	}
 }
 
@@ -478,9 +494,13 @@ espconn_tcp_sent(void *arg, uint8 *psent, uint16 length)
 			err = tcp_write(pcb, psent, len, 0);
 
         if (err == ERR_MEM) {
-            len /= 2;
+			if(len < 3)
+				len--;
+			else
+            	len /= 2;
         }
-    } while (err == ERR_MEM && len > 1);
+
+    } while (err == ERR_MEM && len > 0);
 
 	/*Find out what we can send and send it, offset the buffer point for next send*/
     if (err == ERR_OK) {
@@ -615,7 +635,37 @@ espconn_recv_unhold(struct espconn *pespconn)
 }
 
 //***********Code for WIFI_BLOCK from upper**************
+sint8 ICACHE_FLASH_ATTR
+espconn_lock_recv(espconn_msg *plockmsg)
+{
+	if (plockmsg == NULL || plockmsg->pespconn == NULL) {
+		return ESPCONN_ARG;
+	}
+
+	if (plockmsg->pespconn->recv_callback == NULL){
+		if (plockmsg->readbuf == NULL){
+			plockmsg->readbuf = ringbuf_new(TCP_WND);
+			if (plockmsg->readbuf == NULL)
+				return ESPCONN_MEM;
+		}
+		return espconn_recv_hold(plockmsg->pespconn);
+	}
 
+	return ESPCONN_OK;
+}
+
+sint8 ICACHE_FLASH_ATTR
+espconn_unlock_recv(espconn_msg *punlockmsg)
+{
+	if (punlockmsg == NULL || punlockmsg->pespconn == NULL) {
+		return ESPCONN_ARG;
+	}
+
+	if (punlockmsg->pespconn->recv_callback != NULL)
+		return espconn_recv_unhold(punlockmsg->pespconn);
+
+	return ESPCONN_OK;
+}
 /******************************************************************************
  * FunctionName : espconn_client_recv
  * Description  : Data has been received on this pcb.
@@ -631,6 +681,8 @@ espconn_client_recv(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err)
 	espconn_msg *precv_cb = arg;
 
 	tcp_arg(pcb, arg);
+	/*lock the window because of application layer don't need the data*/
+	espconn_lock_recv(precv_cb);
 
     if (p != NULL) {
     	/*To update and advertise a larger window*/
@@ -640,30 +692,38 @@ espconn_client_recv(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err)
 			precv_cb->recv_holded_buf_Len += p->tot_len;
     }
 
-    if (err == ERR_OK && p != NULL) {
-    	char *pdata = NULL;
-    	u16_t length = 0;
-    	/*Copy the contents of a packet buffer to an application buffer.
-    	 *to prevent memory leaks, ensure that each allocated is deleted*/
-        pdata = (char *)os_zalloc(p ->tot_len + 1);
-        length = pbuf_copy_partial(p, pdata, p ->tot_len, 0);
-        pbuf_free(p);
-
-        if (length != 0) {
-        	/*switch the state of espconn for application process*/
-        	precv_cb->pespconn ->state = ESPCONN_READ;
-        	precv_cb->pcommon.pcb = pcb;
-            if (precv_cb->pespconn->recv_callback != NULL) {
-            	precv_cb->pespconn->recv_callback(precv_cb->pespconn, pdata, length);
-            }
-            /*switch the state of espconn for next packet copy*/
-            if (pcb->state == ESTABLISHED)
-            	precv_cb->pespconn ->state = ESPCONN_CONNECT;
-        }
+    if (precv_cb->pespconn->recv_callback != NULL){
+		if (err == ERR_OK && p != NULL) {
+			char *pdata = NULL;
+			u16_t length = 0;
+			/*Copy the contents of a packet buffer to an application buffer.
+			 *to prevent memory leaks, ensure that each allocated is deleted*/
+			pdata = (char *)os_zalloc(p ->tot_len + 1);
+			length = pbuf_copy_partial(p, pdata, p ->tot_len, 0);
+			pbuf_free(p);
+
+			if (length != 0) {
+				/*switch the state of espconn for application process*/
+				precv_cb->pespconn ->state = ESPCONN_READ;
+				precv_cb->pcommon.pcb = pcb;
+				precv_cb->pespconn->recv_callback(precv_cb->pespconn, pdata, length);
+
+				/*switch the state of espconn for next packet copy*/
+				if (pcb->state == ESTABLISHED)
+					precv_cb->pespconn ->state = ESPCONN_CONNECT;
+			}
 
-        /*to prevent memory leaks, ensure that each allocated is deleted*/
-        os_free(pdata);
-        pdata = NULL;
+			/*to prevent memory leaks, ensure that each allocated is deleted*/
+			os_free(pdata);
+			pdata = NULL;
+		}
+    } else{
+    	/*unregister receive function*/
+    	struct pbuf *pthis = NULL;
+    	for (pthis = p; pthis != NULL; pthis = pthis->next) {
+    		ringbuf_memcpy_into(precv_cb->readbuf, pthis->payload, pthis->len);
+    		pbuf_free(pthis);
+    	}
     }
 
     if (err == ERR_OK && p == NULL) {
@@ -877,6 +937,8 @@ espconn_client_connect(void *arg, struct tcp_pcb *tpcb, err_t err)
 		if (espconn_keepalive_disabled(pcon))
 			espconn_keepalive_enable(tpcb);
 
+//		/*lock the window because of application layer don't need the data*/
+//		espconn_lock_recv(pcon);
     } else{
     	os_printf("err in host connected (%s)\n",lwip_strerr(err));
     }
@@ -1015,6 +1077,9 @@ espconn_server_recv(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err)
 
     tcp_arg(pcb, arg);
     espconn_printf("server has application data received: %d\n", system_get_free_heap_size());
+    /*lock the window because of application layer don't need the data*/
+    espconn_lock_recv(precv_cb);
+
     if (p != NULL) {
     	/*To update and advertise a larger window*/
 		if(precv_cb->recv_hold_flag == 0)
@@ -1023,42 +1088,47 @@ espconn_server_recv(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err)
 			precv_cb->recv_holded_buf_Len += p->tot_len;
     }
 
-    if (err == ERR_OK && p != NULL) {
-    	u8_t *data_ptr = NULL;
-    	u32_t data_cntr = 0;
-    	/*clear the count for connection timeout*/
-		precv_cb->pcommon.recv_check = 0;
-		/*Copy the contents of a packet buffer to an application buffer.
-		 *to prevent memory leaks, ensure that each allocated is deleted*/
-        data_ptr = (u8_t *)os_zalloc(p ->tot_len + 1);
-        data_cntr = pbuf_copy_partial(p, data_ptr, p ->tot_len, 0);
-        pbuf_free(p);
-
-        if (data_cntr != 0) {
-        	/*switch the state of espconn for application process*/
-        	precv_cb->pespconn ->state = ESPCONN_READ;
-        	precv_cb->pcommon.pcb = pcb;
-            if (precv_cb->pespconn->recv_callback != NULL) {
-            	precv_cb->pespconn->recv_callback(precv_cb->pespconn, data_ptr, data_cntr);
-            }
-
-            /*switch the state of espconn for next packet copy*/
-            if (pcb->state == ESTABLISHED)
-            	precv_cb->pespconn ->state = ESPCONN_CONNECT;
-        }
-
-        /*to prevent memory leaks, ensure that each allocated is deleted*/
-        os_free(data_ptr);
-        data_ptr = NULL;
-        espconn_printf("server's application data has been processed: %d\n", system_get_free_heap_size());
-    } else {
-        if (p != NULL) {
-            pbuf_free(p);
-        }
+    /*register receive function*/
+	if (precv_cb->pespconn->recv_callback != NULL) {
+		if (err == ERR_OK && p != NULL) {
+			u8_t *data_ptr = NULL;
+			u32_t data_cntr = 0;
+			/*clear the count for connection timeout*/
+			precv_cb->pcommon.recv_check = 0;
+			/*Copy the contents of a packet buffer to an application buffer.
+			 *to prevent memory leaks, ensure that each allocated is deleted*/
+			data_ptr = (u8_t *) os_zalloc(p ->tot_len + 1);
+			data_cntr = pbuf_copy_partial(p, data_ptr, p->tot_len, 0);
+			pbuf_free(p);
+
+			if (data_cntr != 0) {
+				/*switch the state of espconn for application process*/
+				precv_cb->pespconn->state = ESPCONN_READ;
+				precv_cb->pcommon.pcb = pcb;
+				precv_cb->pespconn->recv_callback(precv_cb->pespconn, data_ptr, data_cntr);
+
+				/*switch the state of espconn for next packet copy*/
+				if (pcb->state == ESTABLISHED)
+					precv_cb->pespconn->state = ESPCONN_CONNECT;
+			}
 
-        espconn_server_close(precv_cb, pcb,0);
-    }
+			/*to prevent memory leaks, ensure that each allocated is deleted*/
+			os_free(data_ptr);
+			data_ptr = NULL;
+			espconn_printf("server's application data has been processed: %d\n", system_get_free_heap_size());
+		}
+	} else {
+		/*unregister receive function*/
+		struct pbuf *pthis = NULL;
+		for (pthis = p; pthis != NULL; pthis = pthis->next) {
+			ringbuf_memcpy_into(precv_cb->readbuf, pthis->payload, pthis->len);
+			pbuf_free(pthis);
+		}
+	}
 
+	if (err == ERR_OK && p == NULL) {
+		espconn_server_close(precv_cb, pcb, 0);
+	}
     return ERR_OK;
 }
 
@@ -1292,6 +1362,8 @@ espconn_tcp_accept(void *arg, struct tcp_pcb *pcb, err_t err)
 	if (espconn_keepalive_disabled(paccept))
 		espconn_keepalive_enable(pcb);
 
+//	/*lock the window because of application layer don't need the data*/
+//	espconn_lock_recv(paccept);
     return ERR_OK;
 }
 
diff --git a/tools/sdk/lwip/src/app/espconn_udp.c b/tools/sdk/lwip/src/app/espconn_udp.c
index 6e6b0ab4e8..e3ac8e60f2 100644
--- a/tools/sdk/lwip/src/app/espconn_udp.c
+++ b/tools/sdk/lwip/src/app/espconn_udp.c
@@ -94,8 +94,8 @@ espconn_udp_sent(void *arg, uint8 *psent, uint16 length)
         return ESPCONN_ARG;
     }
 
-    if (1470 < length) {
-        datalen = 1470;
+    if ((IP_FRAG_MAX_MTU - 20 - 8) < length) {
+        datalen = IP_FRAG_MAX_MTU - 20 - 8;
     } else {
         datalen = length;
     }
@@ -200,8 +200,8 @@ espconn_udp_sendto(void *arg, uint8 *psent, uint16 length)
         return ESPCONN_ARG;
     }
 
-    if (1470 < length) {
-        datalen = 1470;
+    if ((IP_FRAG_MAX_MTU - 20 - 8) < length) {
+        datalen = IP_FRAG_MAX_MTU - 20 - 8;
     } else {
         datalen = length;
     }
diff --git a/tools/sdk/lwip/src/core/dhcp.c b/tools/sdk/lwip/src/core/dhcp.c
old mode 100644
new mode 100755
index 342543ea0a..17b2a47e10
--- a/tools/sdk/lwip/src/core/dhcp.c
+++ b/tools/sdk/lwip/src/core/dhcp.c
@@ -1096,12 +1096,12 @@ dhcp_renew(struct netif *netif)
     }
 #endif /* LWIP_NETIF_HOSTNAME */
 
-#if 0
+#if 1
     dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4);
     dhcp_option_long(dhcp, ntohl(dhcp->offered_ip_addr.addr));
 #endif
 
-#if 0
+#if 1
     dhcp_option(dhcp, DHCP_OPTION_SERVER_ID, 4);
     dhcp_option_long(dhcp, ntohl(dhcp->server_ip_addr.addr));
 #endif
@@ -1159,7 +1159,7 @@ dhcp_rebind(struct netif *netif)
     }
 #endif /* LWIP_NETIF_HOSTNAME */
 
-#if 0
+#if 1
     dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4);
     dhcp_option_long(dhcp, ntohl(dhcp->offered_ip_addr.addr));
 
diff --git a/tools/sdk/lwip/src/core/dns.c b/tools/sdk/lwip/src/core/dns.c
old mode 100644
new mode 100755
index a98095d0a5..5e75f6d5af
--- a/tools/sdk/lwip/src/core/dns.c
+++ b/tools/sdk/lwip/src/core/dns.c
@@ -227,7 +227,7 @@ static ip_addr_t              dns_servers[DNS_MAX_SERVERS];
 /** Contiguous buffer for processing responses */
 //static u8_t                   dns_payload_buffer[LWIP_MEM_ALIGN_BUFFER(DNS_MSG_SIZE)];
 static u8_t*                  dns_payload;
-static u8_t					  dns_random;
+static u16_t					  dns_random;
 /**
  * Initialize the resolver: set up the UDP pcb and configure the default server
  * (DNS_SERVER_ADDRESS).
@@ -570,7 +570,7 @@ dns_send(u8_t numdns, const char* name, u8_t id)
   char *query, *nptr;
   const char *pHostname;
   u8_t n;
-  dns_random = os_random()%250;
+  dns_random = os_random()>>16;
   LWIP_DEBUGF(DNS_DEBUG, ("dns_send: dns_servers[%"U16_F"] \"%s\": request\n",
               (u16_t)(numdns), name));
   LWIP_ASSERT("dns server out of array", numdns < DNS_MAX_SERVERS);
@@ -698,7 +698,7 @@ dns_check_entry(u8_t i)
 
     case DNS_STATE_DONE: {
       /* if the time to live is nul */
-      if (--pEntry->ttl == 0) {
+      if ((pEntry->ttl == 0) || (--pEntry->ttl == 0)) {
         LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": flush\n", pEntry->name));
         /* flush this entry */
         pEntry->state = DNS_STATE_UNUSED;
@@ -825,6 +825,13 @@ dns_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t
             if (pEntry->found) {
               (*pEntry->found)(pEntry->name, &pEntry->ipaddr, pEntry->arg);
             }
+            if (pEntry->ttl == 0) {
+              /* RFC 883, page 29: "Zero values are
+                 interpreted to mean that the RR can only be used for the
+                 transaction in progress, and should not be cached."
+                 -> flush this entry now */
+              goto flushentry;
+            }
             /* deallocate memory and return */
             goto memerr;
           } else {
@@ -847,6 +854,7 @@ dns_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t
   if (pEntry->found) {
     (*pEntry->found)(pEntry->name, NULL, pEntry->arg);
   }
+flushentry:
   /* flush this entry */
   pEntry->state = DNS_STATE_UNUSED;
   pEntry->found = NULL;
diff --git a/tools/sdk/lwip/src/core/ipv4/igmp.c b/tools/sdk/lwip/src/core/ipv4/igmp.c
index 90c82a6319..9c07fd6bc3 100644
--- a/tools/sdk/lwip/src/core/ipv4/igmp.c
+++ b/tools/sdk/lwip/src/core/ipv4/igmp.c
@@ -149,7 +149,7 @@ static err_t  igmp_ip_output_if(struct pbuf *p, ip_addr_t *src, ip_addr_t *dest,
 static void   igmp_send(struct igmp_group *group, u8_t type)ICACHE_FLASH_ATTR;
 
 
-static struct igmp_group* igmp_group_list;
+static struct igmp_group* igmp_group_list = NULL;
 static ip_addr_t     allsystems;
 static ip_addr_t     allrouters;
 
diff --git a/tools/sdk/lwip/src/core/netif.c b/tools/sdk/lwip/src/core/netif.c
index 6913b408f6..cb6b6a84e6 100644
--- a/tools/sdk/lwip/src/core/netif.c
+++ b/tools/sdk/lwip/src/core/netif.c
@@ -486,6 +486,10 @@ void netif_set_up(struct netif *netif)
  */ 
 void netif_set_down(struct netif *netif)
 {
+  if (netif == NULL) {	
+    return;
+  }
+
   if (netif->flags & NETIF_FLAG_UP) {
     netif->flags &= ~NETIF_FLAG_UP;
 #if LWIP_SNMP
diff --git a/tools/sdk/lwip/src/core/sntp.c b/tools/sdk/lwip/src/core/sntp.c
old mode 100644
new mode 100755
index 745ba399c0..0aa26b91ce
--- a/tools/sdk/lwip/src/core/sntp.c
+++ b/tools/sdk/lwip/src/core/sntp.c
@@ -51,7 +51,7 @@
 #include "lwip/dns.h"
 #include "lwip/ip_addr.h"
 #include "lwip/pbuf.h"
-
+#include "lwip/app/time.h"
 //#include <string.h>
 #if LWIP_UDP
 
@@ -148,14 +148,18 @@
 #endif
 
 /** SNTP macro to change system time including microseconds */
-#ifdef SNTP_SET_SYSTEM_TIME_US
-#define SNTP_CALC_TIME_US           1
-#define SNTP_RECEIVE_TIME_SIZE      2
-#else
-#define SNTP_SET_SYSTEM_TIME_US(sec, us)
-#define SNTP_CALC_TIME_US           0
-#define SNTP_RECEIVE_TIME_SIZE      1
-#endif
+uint8 sntp_receive_time_size = 1;
+#define SNTP_RECEIVE_TIME_SIZE      sntp_receive_time_size
+#define SNTP_SET_SYSTEM_TIME_US(sec, us)	sntp_update_rtc(sec, us)
+//#ifdef SNTP_SET_SYSTEM_TIME_US
+//#define SNTP_SET_SYSTEM_TIME_US(sec, us)	sntp_update_rtc(sec, us)
+//#define SNTP_CALC_TIME_US           1
+//#define SNTP_RECEIVE_TIME_SIZE      2
+//#else
+//#define SNTP_SET_SYSTEM_TIME_US(sec, us)
+//#define SNTP_CALC_TIME_US           0
+//#define SNTP_RECEIVE_TIME_SIZE      sntp_receive_time_size
+//#endif
 
 /** SNTP macro to get system time, used with SNTP_CHECK_RESPONSE >= 2
  * to send in request and compare in response.
@@ -295,10 +299,12 @@ static ip_addr_t sntp_last_server_address;
  * to compare against in response */
 static u32_t sntp_last_timestamp_sent[2];
 #endif /* SNTP_CHECK_RESPONSE >= 2 */
-typedef long     time_t;
+
 //uint32 current_stamp_1 = 0;
 //uint32 current_stamp_2 = 0;
-uint32 realtime_stamp = 0;
+static bool sntp_time_flag = false;
+static uint32 sntp_update_delay = SNTP_UPDATE_DELAY;
+static uint32 realtime_stamp = 0;
 LOCAL os_timer_t sntp_timer;
 /*****************************************/
 #define SECSPERMIN	60L
@@ -643,13 +649,24 @@ bool ICACHE_FLASH_ATTR
 sntp_set_timezone(sint8 timezone)
 {
 	if(timezone >= -11 || timezone <= 13) {
-		time_zone = timezone;
+		if (sntp_get_timetype()){
+			RTC_TZ_SET(time_zone);
+		} else
+			time_zone = timezone;
 		return true;
 	} else {
 		return false;
 	}
 
 }
+
+void ICACHE_FLASH_ATTR sntp_set_daylight(int daylight)
+{
+	if (sntp_get_timetype()){
+		RTC_DST_SET(daylight);
+	}
+}
+
 void ICACHE_FLASH_ATTR
 sntp_time_inc(void)
 {
@@ -665,7 +682,22 @@ sntp_process(u32_t *receive_timestamp)
    * @todo: if MSB is 1, SNTP time is 2036-based!
    */
   time_t t = (ntohl(receive_timestamp[0]) - DIFF_SEC_1900_1970);
-
+  if (sntp_get_timetype()){
+	  u32_t us = ntohl(receive_timestamp[1]) / 4295;
+	    SNTP_SET_SYSTEM_TIME_US(t, us);
+	    /* display local time from GMT time */
+	    LWIP_DEBUGF(SNTP_DEBUG_TRACE, ("sntp_process: %s, %"U32_F" us", ctime(&t), us));
+  } else{
+	  /* change system time and/or the update the RTC clock */
+	    SNTP_SET_SYSTEM_TIME(t);
+	    /* display local time from GMT time */
+	    t += time_zone * 60 * 60;// format GMT + time_zone TIME ZONE
+	    realtime_stamp = t;
+	    os_timer_disarm(&sntp_timer);
+	    os_timer_setfn(&sntp_timer, (os_timer_func_t *)sntp_time_inc, NULL);
+	    os_timer_arm(&sntp_timer, 1000, 1);
+  }
+#if 0
 #if SNTP_CALC_TIME_US
   u32_t us = ntohl(receive_timestamp[1]) / 4295;
   SNTP_SET_SYSTEM_TIME_US(t, us);
@@ -682,10 +714,8 @@ sntp_process(u32_t *receive_timestamp)
   os_timer_disarm(&sntp_timer);
   os_timer_setfn(&sntp_timer, (os_timer_func_t *)sntp_time_inc, NULL);
   os_timer_arm(&sntp_timer, 1000, 1);
-  os_printf("%s\n",sntp_asctime(sntp_localtime (&t)));
-//  os_printf("%s\n",ctime(&t));
-//  LWIP_DEBUGF(SNTP_DEBUG_TRACE, ("sntp_process: %s", ctime(&t)));
 #endif /* SNTP_CALC_TIME_US */
+#endif
 }
 
 /**
@@ -856,9 +886,9 @@ sntp_recv(void *arg, struct udp_pcb* pcb, struct pbuf *p, ip_addr_t *addr, u16_t
     sntp_process(receive_timestamp);
 
     /* Set up timeout for next request */
-    sys_timeout((u32_t)SNTP_UPDATE_DELAY, sntp_request, NULL);
+    sys_timeout((u32_t)sntp_update_delay, sntp_request, NULL);
     LWIP_DEBUGF(SNTP_DEBUG_STATE, ("sntp_recv: Scheduled next time request: %"U32_F" ms\n",
-      (u32_t)SNTP_UPDATE_DELAY));
+      (u32_t)sntp_update_delay));
   } else if (err == SNTP_ERR_KOD) {
     /* Kiss-of-death packet. Use another server or increase UPDATE_DELAY. */
     sntp_try_next_server(NULL);
@@ -1125,4 +1155,31 @@ sntp_getservername(u8_t idx)
 }
 #endif /* SNTP_SERVER_DNS */
 
+void ICACHE_FLASH_ATTR
+sntp_set_update_delay(uint32 ms)
+{
+	sntp_update_delay = ms > 15000?ms:15000;
+}
+
+void ICACHE_FLASH_ATTR
+sntp_set_timetype(bool type)
+{
+	// sntp_time_flag = type;
+}
+
+bool sntp_get_timetype(void)
+{
+	return sntp_time_flag;
+}
+
+void ICACHE_FLASH_ATTR
+sntp_set_receive_time_size(void)
+{
+	if (sntp_get_timetype()){
+		sntp_receive_time_size = 2;
+	} else{
+		sntp_receive_time_size = 1;
+	}
+}
+
 #endif /* LWIP_UDP */
diff --git a/tools/sdk/version b/tools/sdk/version
index 82c7dcf1da..70665c512c 100644
--- a/tools/sdk/version
+++ b/tools/sdk/version
@@ -1 +1 @@
-1.5.4_16_05_20
\ No newline at end of file
+2.0.0_16_08_09
\ No newline at end of file