diff --git a/components/app_update/esp_ota_ops.c b/components/app_update/esp_ota_ops.c
index 8b1a43163e..23b6f870c6 100644
--- a/components/app_update/esp_ota_ops.c
+++ b/components/app_update/esp_ota_ops.c
@@ -106,6 +106,7 @@ esp_err_t esp_ota_begin(const esp_partition_t *partition, size_t image_size, esp
 
 esp_err_t esp_ota_write(esp_ota_handle_t handle, const void *data, size_t size)
 {
+    const uint8_t *data_bytes = (const uint8_t *)data;
     esp_err_t ret;
     ota_ops_entry_t *it;
 
@@ -119,6 +120,12 @@ esp_err_t esp_ota_write(esp_ota_handle_t handle, const void *data, size_t size)
         if (it->handle == handle) {
             // must erase the partition before writing to it
             assert(it->erased_size > 0 && "must erase the partition before writing to it");
+
+            if(it->wrote_size == 0 && size > 0 && data_bytes[0] != 0xE9) {
+                ESP_LOGE(TAG, "OTA image has invalid magic byte (expected 0xE9, saw 0x%02x", data_bytes[0]);
+                return ESP_ERR_OTA_VALIDATE_FAILED;
+            }
+
             ret = esp_partition_write(&it->part, it->wrote_size, data, size);
             if(ret == ESP_OK){
                 it->wrote_size += size;
@@ -135,6 +142,7 @@ esp_err_t esp_ota_write(esp_ota_handle_t handle, const void *data, size_t size)
 esp_err_t esp_ota_end(esp_ota_handle_t handle)
 {
     ota_ops_entry_t *it;
+    size_t image_size;
     for (it = LIST_FIRST(&s_ota_ops_entries_head); it != NULL; it = LIST_NEXT(it, entries)) {
         if (it->handle == handle) {
             // an ota handle need to be ended after erased and wrote data in it
@@ -142,12 +150,12 @@ esp_err_t esp_ota_end(esp_ota_handle_t handle)
                 return ESP_ERR_INVALID_ARG;
             }
 
-#ifdef CONFIG_SECUREBOOTLOADER
-            esp_err_t ret;
-            size_t image_size;
-            if (esp_image_basic_verify(it->part.address, &image_size) != ESP_OK) {
+            if (esp_image_basic_verify(it->part.address, true, &image_size) != ESP_OK) {
                 return ESP_ERR_OTA_VALIDATE_FAILED;
             }
+
+#ifdef CONFIG_SECURE_BOOT_ENABLED
+            esp_err_t ret;
             ret = esp_secure_boot_verify_signature(it->part.address, image_size);
             if (ret != ESP_OK) {
                 return ESP_ERR_OTA_VALIDATE_FAILED;
@@ -285,17 +293,18 @@ static esp_err_t esp_rewrite_ota_data(esp_partition_subtype_t subtype)
 
 esp_err_t esp_ota_set_boot_partition(const esp_partition_t *partition)
 {
+    size_t image_size;
     const esp_partition_t *find_partition = NULL;
     if (partition == NULL) {
         return ESP_ERR_INVALID_ARG;
     }
 
-#ifdef CONFIG_SECUREBOOTLOADER
-    size_t image_size;
-    if (esp_image_basic_verify(partition->address, &image_size) != ESP_OK) {
+    if (esp_image_basic_verify(partition->address, true, &image_size) != ESP_OK) {
         return ESP_ERR_OTA_VALIDATE_FAILED;
     }
-    ret = esp_secure_boot_verify_signature(partition->address, image_size);
+
+#ifdef CONFIG_SECURE_BOOT_ENABLED
+    esp_err_t ret = esp_secure_boot_verify_signature(partition->address, image_size);
     if (ret != ESP_OK) {
         return ESP_ERR_OTA_VALIDATE_FAILED;
     }
diff --git a/examples/system/ota/main/ota.c b/examples/system/ota/main/ota.c
index 4956129e5d..21ebcc3c21 100644
--- a/examples/system/ota/main/ota.c
+++ b/examples/system/ota/main/ota.c
@@ -95,7 +95,7 @@ static void initialise_wifi(void)
 }
 
 /*read buffer by byte still delim ,return read bytes counts*/
-int read_until(char *buffer, char delim, int len)
+static int read_until(char *buffer, char delim, int len)
 {
 //  /*TODO: delim check,buffer check,further: do an buffer length limited*/
     int i = 0;
@@ -109,7 +109,7 @@ int read_until(char *buffer, char delim, int len)
  * return true if packet including \r\n\r\n that means http packet header finished,start to receive packet body
  * otherwise return false
  * */
-bool resolve_pkg(char text[], int total_len, esp_ota_handle_t out_handle)
+static bool read_past_http_header(char text[], int total_len, esp_ota_handle_t out_handle)
 {
     /* i means current position */
     int i = 0, i_read_len = 0;
@@ -121,13 +121,6 @@ bool resolve_pkg(char text[], int total_len, esp_ota_handle_t out_handle)
             memset(ota_write_data, 0, BUFFSIZE);
             /*copy first http packet body to write buffer*/
             memcpy(ota_write_data, &(text[i + 2]), i_write_len);
-            /*check write packet header first byte:0xE9 second byte:0x09 */
-            if (ota_write_data[0] == 0xE9 && i_write_len >= 2 && ota_write_data[1] == 0x09) {
-                ESP_LOGI(TAG, "OTA Write Header format Check OK. first byte is %02x ,second byte is %02x", ota_write_data[0], ota_write_data[1]);
-            } else {
-                ESP_LOGE(TAG, "OTA Write Header format Check Failed! first byte is %02x ,second byte is %02x", ota_write_data[0], ota_write_data[1]);
-                return false;
-            }
 
             esp_err_t err = esp_ota_write( out_handle, (const void *)ota_write_data, i_write_len);
             if (err != ESP_OK) {
@@ -266,7 +259,7 @@ void main_task(void *pvParameter)
         task_fatal_error();
     }
 
-    bool pkg_body_start = false, flag = true;
+    bool resp_body_start = false, flag = true;
     /*deal with all receive packet*/
     while (flag) {
         memset(text, 0, TEXT_BUFFSIZE);
@@ -275,10 +268,10 @@ void main_task(void *pvParameter)
         if (buff_len < 0) { /*receive error*/
             ESP_LOGE(TAG, "Error: receive data error! errno=%d", errno);
             task_fatal_error();
-        } else if (buff_len > 0 && !pkg_body_start) { /*deal with packet header*/
+        } else if (buff_len > 0 && !resp_body_start) { /*deal with response header*/
             memcpy(ota_write_data, text, buff_len);
-            pkg_body_start = resolve_pkg(text, buff_len, out_handle);
-        } else if (buff_len > 0 && pkg_body_start) { /*deal with packet body*/
+            resp_body_start = read_past_http_header(text, buff_len, out_handle);
+        } else if (buff_len > 0 && resp_body_start) { /*deal with response body*/
             memcpy(ota_write_data, text, buff_len);
             err = esp_ota_write( out_handle, (const void *)ota_write_data, buff_len);
             if (err != ESP_OK) {