diff --git a/components/ethernet/eth_phy/phy_common.c b/components/ethernet/eth_phy/phy_common.c
index a72a6daf8..88e5d0c73 100644
--- a/components/ethernet/eth_phy/phy_common.c
+++ b/components/ethernet/eth_phy/phy_common.c
@@ -41,8 +41,10 @@ void phy_rmii_configure_data_interface_pins(void)
 void phy_rmii_smi_configure_pins(uint8_t mdc_gpio, uint8_t mdio_gpio)
 {
     gpio_matrix_out(mdc_gpio, EMAC_MDC_O_IDX, 0, 0);
+    PIN_FUNC_SELECT(GPIO_PIN_MUX_REG[mdc_gpio], PIN_FUNC_GPIO);
     gpio_matrix_out(mdio_gpio, EMAC_MDO_O_IDX, 0, 0);
     gpio_matrix_in(mdio_gpio, EMAC_MDI_I_IDX, 0);
+    PIN_FUNC_SELECT(GPIO_PIN_MUX_REG[mdio_gpio], PIN_FUNC_GPIO);
 }
 
 void phy_mii_enable_flow_ctrl(void)
diff --git a/components/freertos/include/freertos/FreeRTOSConfig.h b/components/freertos/include/freertos/FreeRTOSConfig.h
index 5f5cebc6b..37912a66c 100644
--- a/components/freertos/include/freertos/FreeRTOSConfig.h
+++ b/components/freertos/include/freertos/FreeRTOSConfig.h
@@ -253,6 +253,7 @@ int xt_clock_freq(void) __attribute__((deprecated));
 #define INCLUDE_uxTaskGetStackHighWaterMark	1
 #define INCLUDE_pcTaskGetTaskName			1
 #define INCLUDE_xTaskGetIdleTaskHandle      1
+#define INCLUDE_pxTaskGetStackStart			1
 
 #define INCLUDE_xSemaphoreGetMutexHolder    1
 
diff --git a/components/freertos/tasks.c b/components/freertos/tasks.c
index bdfe1086c..ff549183a 100644
--- a/components/freertos/tasks.c
+++ b/components/freertos/tasks.c
@@ -3814,14 +3814,17 @@ BaseType_t xTaskGetAffinity( TaskHandle_t xTask )
 /*-----------------------------------------------------------*/
 
 #if (INCLUDE_pxTaskGetStackStart == 1)
-   uint8_t* pxTaskGetStackStart( TaskHandle_t xTask)
-   {
-   TCB_t *pxTCB;
-   UBaseType_t uxReturn;
 
-       pxTCB = prvGetTCBFromHandle( xTask );
-       return ( uint8_t * ) pxTCB->pxStack;
-   }
+	uint8_t* pxTaskGetStackStart( TaskHandle_t xTask)
+	{
+		TCB_t *pxTCB;
+		uint8_t* uxReturn;
+
+		pxTCB = prvGetTCBFromHandle( xTask );
+		uxReturn = (uint8_t*)pxTCB->pxStack;
+
+		return uxReturn;
+	}
 
 #endif /* INCLUDE_pxTaskGetStackStart */
 /*-----------------------------------------------------------*/
diff --git a/components/log/include/esp_log.h b/components/log/include/esp_log.h
index 085970c51..e525bca3c 100644
--- a/components/log/include/esp_log.h
+++ b/components/log/include/esp_log.h
@@ -55,11 +55,14 @@ void esp_log_level_set(const char* tag, esp_log_level_t level);
  * @brief Set function used to output log entries
  *
  * By default, log output goes to UART0. This function can be used to redirect log
- * output to some other destination, such as file or network.
+ * output to some other destination, such as file or network. Returns the original
+ * log handler, which may be necessary to return output to the previous destination.
  *
- * @param func Function used for output. Must have same signature as vprintf.
+ * @param func new Function used for output. Must have same signature as vprintf.
+ *
+ * @return func old Function used for output.
  */
-void esp_log_set_vprintf(vprintf_like_t func);
+vprintf_like_t esp_log_set_vprintf(vprintf_like_t func);
 
 /**
  * @brief Function which returns timestamp to be used in log output
diff --git a/components/log/log.c b/components/log/log.c
index 038e8e163..370c8b01c 100644
--- a/components/log/log.c
+++ b/components/log/log.c
@@ -106,9 +106,18 @@ static inline void heap_swap(int i, int j);
 static inline bool should_output(esp_log_level_t level_for_message, esp_log_level_t level_for_tag);
 static inline void clear_log_level_list();
 
-void esp_log_set_vprintf(vprintf_like_t func)
+vprintf_like_t esp_log_set_vprintf(vprintf_like_t func)
 {
+    if (!s_log_mutex) {
+        s_log_mutex = xSemaphoreCreateMutex();
+    }
+    xSemaphoreTake(s_log_mutex, portMAX_DELAY);
+
+    vprintf_like_t orig_func = s_log_print_func;
     s_log_print_func = func;
+
+    xSemaphoreGive(s_log_mutex);
+    return orig_func;
 }
 
 void esp_log_level_set(const char* tag, esp_log_level_t level)
diff --git a/components/soc/esp32/include/soc/io_mux_reg.h b/components/soc/esp32/include/soc/io_mux_reg.h
index be07c6bcd..2598989d0 100644
--- a/components/soc/esp32/include/soc/io_mux_reg.h
+++ b/components/soc/esp32/include/soc/io_mux_reg.h
@@ -72,7 +72,6 @@
 #define MCU_SEL_M (MCU_SEL_V << MCU_SEL_S)
 #define MCU_SEL_V 0x7
 #define MCU_SEL_S 12
-#define MCU_SEL_V 0x7
 
 #define PIN_INPUT_ENABLE(PIN_NAME)               SET_PERI_REG_MASK(PIN_NAME,FUN_IE)
 #define PIN_INPUT_DISABLE(PIN_NAME)              CLEAR_PERI_REG_MASK(PIN_NAME,FUN_IE)