diff --git a/src/espmega_iot_core.cpp b/src/espmega_iot_core.cpp
index 713bfbb..7b92f4b 100644
--- a/src/espmega_iot_core.cpp
+++ b/src/espmega_iot_core.cpp
@@ -546,13 +546,21 @@ void ota_begin()
     otaserver.sendHeader("Connection","close");
   },[](){
     HTTPUpload &upload = otaserver.upload();
+    size_t file_size = 0;
     if(upload.status == UPLOAD_FILE_START) {
-      Serial.println(upload.totalSize);
+      for(int i=0;i<otaserver.headers();i++) {
+        if(!otaserver.headerName(i).compareTo("Content-Length")) {
+          Serial.printf("Content-Length: %s\n",otaserver.header(i).c_str());
+          file_size = otaserver.header(i).toInt();
+        }
+      }
+      
+      Serial.println(file_size);
+      lcd_upload_start(file_size);
     } else if (upload.status == UPLOAD_FILE_WRITE) {
-      for(int i = 0; i<upload.currentSize;i++)
-        Serial.print(upload.buf[i],HEX);
+      lcd_upload_write(upload.buf, upload.currentSize);
     } else if (upload.status == UPLOAD_FILE_END) {
-        Serial.println("Upload End");
+      Serial.println("Upload END.");
     }
   });
   otaserver.begin();
diff --git a/src/espmega_iot_lcd.cpp b/src/espmega_iot_lcd.cpp
index 1f03338..0628433 100644
--- a/src/espmega_iot_lcd.cpp
+++ b/src/espmega_iot_lcd.cpp
@@ -1,9 +1,11 @@
 #include <user_code.hpp>
 #include <espmega_iot_lcd.hpp>
 
+int lcd_byte_counter = 0;
+
 /**
  * @brief Sends stop bit to LCD.
- * 
+ *
  * This function sends a stop bit to the LCD. It is only enabled if the ENABLE_INTERNAL_LCD macro is defined.
  */
 void lcd_send_stop_bit()
@@ -17,7 +19,7 @@ void lcd_send_stop_bit()
 
 /**
  * Sends a command to the LCD display.
- * 
+ *
  * @param command The command to send to the LCD display.
  */
 void lcd_send_command(String command)
@@ -31,9 +33,9 @@ void lcd_send_command(String command)
 
 /**
  * @brief Resets the LCD display.
- * 
+ *
  * If ENABLE_INTERNAL_LCD is defined, sends a reset command to the LCD display.
- * 
+ *
  */
 void lcd_reset()
 {
@@ -57,7 +59,7 @@ void lcd_init()
 
 /**
  * @brief Starts the upload process to the LCD.
- * 
+ *
  * @param size The size of the data to be uploaded.
  * @return true if the upload process started successfully, false otherwise.
  */
@@ -70,14 +72,16 @@ bool lcd_upload_start(size_t size)
     Serial.print("connect");
     lcd_send_stop_bit();
     delay(1000);
-    Serial.print("whmi-wri 1024,115200,res0");
+    Serial.print("whmi-wri ");
+    Serial.print(size);
+    Serial.print(",115200,res0");
     lcd_send_stop_bit();
-    lcd_wait_ack();
+    return lcd_wait_ack();
 }
 
 /**
  * Writes data to the LCD upload buffer.
- * 
+ *
  * @param data Pointer to the data to be written.
  * @param size Size of the data to be written.
  * @return True if the write was successful, false otherwise.
@@ -87,9 +91,15 @@ bool lcd_upload_write(uint8_t *data, size_t size)
     for (int i = 0; i < size; i++)
     {
         Serial.write(data[i]);
+        lcd_byte_counter++;
+        if (lcd_byte_counter == 4096)
+        {
+            lcd_wait_ack();
+            lcd_byte_counter = 0;
+        }
     }
+    return true;
 }
-
 /**
  * Waits for an acknowledgement signal from the LCD.
  * @return true if acknowledgement signal is received, false otherwise.
@@ -97,12 +107,15 @@ bool lcd_upload_write(uint8_t *data, size_t size)
 bool lcd_wait_ack()
 {
     bool data_ok = false;
-    for (int i; i < 50; i++)
+    for (int i = 0; i < 50; i++)
     {
-        if (Serial.read() == 0x05)
+        if (Serial.available())
         {
-            data_ok = true;
-            break;
+            if (Serial.read() == 0x05)
+            {
+                data_ok = true;
+                break;
+            }
         }
         delay(100);
     }
diff --git a/src/ota_html/ota-part3.html b/src/ota_html/ota-part3.html
index b9b4dd4..4c7daee 100644
--- a/src/ota_html/ota-part3.html
+++ b/src/ota_html/ota-part3.html
@@ -28,6 +28,9 @@ R"=====(<button type="button" class="conf" onclick="window.location.href='config
       data: data,
       contentType: false,
       processData: false,
+      headers: {
+        "Content-Length": data.length
+      },
       xhr: function () {
         var xhr = new window.XMLHttpRequest();
         xhr.upload.addEventListener(