diff --git a/tools/sdk/lib/liblwip_gcc.a b/tools/sdk/lib/liblwip_gcc.a
index 0e56b9be7b..c01b09de5d 100644
Binary files a/tools/sdk/lib/liblwip_gcc.a and b/tools/sdk/lib/liblwip_gcc.a differ
diff --git a/tools/sdk/lwip/include/lwip/app/espconn.h b/tools/sdk/lwip/include/lwip/app/espconn.h
index 5167ce1fc5..14fa9bcf90 100644
--- a/tools/sdk/lwip/include/lwip/app/espconn.h
+++ b/tools/sdk/lwip/include/lwip/app/espconn.h
@@ -573,7 +573,7 @@ extern sint8 espconn_get_keepalive(struct espconn *espconn, uint8 level, void *o
  *                - ESPCONN_ARG: dns client not initialized or invalid hostname
 *******************************************************************************/
 
-extern sint8 espconn_gethostbyname(struct espconn *pespconn, const char *name, ip_addr_t *addr, dns_found_callback found);
+extern err_t espconn_gethostbyname(struct espconn *pespconn, const char *name, ip_addr_t *addr, dns_found_callback found);
 
 /******************************************************************************
  * FunctionName : espconn_igmp_join
@@ -674,5 +674,13 @@ extern void espconn_mdns_enable(void);
  *  Returns     : none
 *******************************************************************************/
 extern void espconn_dns_setserver(u8_t numdns, ip_addr_t *dnsserver);
+/******************************************************************************
+ * FunctionName : espconn_dns_getserver
+ * Description  : get dns server.
+ * Parameters   : numdns -- the index of the DNS server ,must
+ * 				  be < DNS_MAX_SERVERS = 2
+ *  Returns     : dnsserver -- struct ip_addr_t
+*******************************************************************************/
+extern ip_addr_t espconn_dns_getserver(u8_t numdns);
 #endif
 
diff --git a/tools/sdk/lwip/src/Makefile b/tools/sdk/lwip/src/Makefile
index 5f65751bdc..26290cfdb0 100644
--- a/tools/sdk/lwip/src/Makefile
+++ b/tools/sdk/lwip/src/Makefile
@@ -1,4 +1,5 @@
-TOOLS_PATH ?= ../../../xtensa-lx106-elf/bin/xtensa-lx106-elf-
+TOOLCHAIN_DIR ?= ../../../xtensa-lx106-elf
+TOOLS_PATH ?= $(TOOLCHAIN_DIR)/bin/xtensa-lx106-elf-
 LWIP_LIB ?= liblwip_src.a
 SDK_PATH ?= $(abspath ../../)
 
@@ -9,6 +10,10 @@ LWIP_INCLUDE = -Ibuild -I$(SDK_PATH)/include -I$(SDK_PATH)/lwip/include
 BUILD_FLAGS = -c -Os -g -Wpointer-arith -Wno-implicit-function-declaration -Wl,-EL -fno-inline-functions -nostdlib -mlongcalls -mtext-section-literals -falign-functions=4 -MMD -std=gnu99 -ffunction-sections -fdata-sections
 BUILD_DEFINES = -D__ets__ -DICACHE_FLASH -U__STRICT_ANSI__ -DLWIP_OPEN_SRC
 
+ifdef WITH_DEBUG_PREFIX_MAP
+EXTRA_FLAGS = -fdebug-prefix-map=$(PWD)= -fdebug-prefix-map=$(TOOLCHAIN_DIR)=xtensa-lx106-elf -gno-record-gcc-switches
+endif
+
 CC=$(TOOLS_PATH)gcc
 AR=$(TOOLS_PATH)ar
 
@@ -18,7 +23,7 @@ $(BUILD_PATH)/%.h:
 
 $(BUILD_PATH)/%.o: %.c
 	@mkdir -p $(dir $@)
-	$(CC) $(BUILD_FLAGS) $(BUILD_DEFINES) $(LWIP_INCLUDE) $< -o $@
+	$(CC) $(BUILD_FLAGS) $(BUILD_DEFINES) $(LWIP_INCLUDE) $(EXTRA_FLAGS) $< -o $@
 
 $(LWIP_LIB): $(BUILD_PATH)/user_config.h $(LWIP_SRCS)
 	$(AR) cru $(LWIP_LIB) $(LWIP_SRCS)