diff --git a/Makefile b/Makefile
index ec1d45b..afec90c 100644
--- a/Makefile
+++ b/Makefile
@@ -20,6 +20,12 @@ buildIdf:
 flashMini:
 	idf.py flash -p /dev/ttyACM0 
 
+flashMini2:
+	idf.py flash -p /dev/ttyACM1
+
+flashMini3:
+	idf.py flash -p /dev/ttyACM2
+
 monitorMini:
 	idf.py monitor -p /dev/ttyACM0 
 
diff --git a/main/CMakeLists.txt b/main/CMakeLists.txt
index b9f1d7f..32831e5 100644
--- a/main/CMakeLists.txt
+++ b/main/CMakeLists.txt
@@ -1,4 +1,4 @@
-idf_component_register(SRCS "main.c" "uart_handler.c" "communication_handler.c" "client_handler.c" "message_parser.c" "message_builder.c" "message_handler.c"
+idf_component_register(SRCS "main.c" "uart_handler.c" "communication_handler.c" "client_handler.c" "message_parser.c" "message_builder.c" "message_handler.c" "ota_update.c"
                        INCLUDE_DIRS ".")
 
 # Get the short Git commit hash of the current HEAD.
diff --git a/main/main.c b/main/main.c
index 6d86f5a..8c16dde 100644
--- a/main/main.c
+++ b/main/main.c
@@ -27,11 +27,12 @@
 #include <sys/types.h>
 
 #include "message_builder.h"
+#include "uart_msg_ids.h"
 
 static const char *TAG = "ALOX - MAIN";
 static const uint16_t version = 0x0001;
 static uint8_t send_message_buffer[1024];
-static uint8_t send_message_payload_buffer[512 - 4];
+static uint8_t send_message_payload_buffer[512];
 
 static MessageBrokerTaskParams_t broker_task_params;
 
@@ -41,8 +42,8 @@ void echoCallback(uint8_t msgid, const uint8_t *payload, size_t payload_len,
                   uint8_t *send_payload_buffer, size_t send_payload_buffer_size,
                   uint8_t *send_buffer, size_t send_buffer_size) {
   ESP_LOGI(TAG, "Echo command 0x01...");
-  int len =
-      build_message(0x01, payload, payload_len, send_buffer, send_buffer_size);
+  int len = build_message(UART_ECHO, payload, payload_len, send_buffer,
+                          send_buffer_size);
   if (len < 0) {
     ESP_LOGE(TAG,
              "Error Building UART Message: payload_len, %d, sendbuffer_size: "
@@ -72,7 +73,9 @@ void versionCallback(uint8_t msgid, const uint8_t *payload, size_t payload_len,
   send_payload_buffer[1] = (uint8_t)((version >> 8) & 0xFF);
   memcpy(&send_payload_buffer[2], &BUILD_GIT_HASH, git_build_hash_len);
 
-  int len = build_message(0x02, send_payload_buffer, needed_buffer_size,
+  // currently running partition
+
+  int len = build_message(UART_VERSION, send_payload_buffer, needed_buffer_size,
                           send_buffer, send_buffer_size);
   if (len < 0) {
     ESP_LOGE(TAG,
@@ -81,7 +84,7 @@ void versionCallback(uint8_t msgid, const uint8_t *payload, size_t payload_len,
              payload_len, send_buffer_size, len);
     return;
   }
-  uart_write_bytes(MASTER_UART, send_buffer, len);
+  uart_write_bytes(MASTER_UART, send_buffer, len - 1);
 }
 
 void clientInfoCallback(uint8_t msgid, const uint8_t *payload,
@@ -131,13 +134,16 @@ void clientInfoCallback(uint8_t msgid, const uint8_t *payload,
              4);
       memcpy(&send_payload_buffer[offset + 13],
              &clientList.Clients[i].lastSuccessfullPing, 4);
-memcpy(&send_payload_buffer[offset + 17],
+      memcpy(&send_payload_buffer[offset + 17],
              &clientList.Clients[i].clientVersion, 2);
     }
   }
 
-  int len = build_message(0x04, send_payload_buffer, needed_buffer_size,
-                          send_buffer, send_buffer_size);
+  int len = build_message(UART_CLIENT_INFO, send_payload_buffer,
+                          needed_buffer_size, send_buffer, send_buffer_size);
+
+  ESP_LOG_BUFFER_HEX("SEND BUFFER: ", send_buffer, send_buffer_size);
+
   if (len < 0) {
     ESP_LOGE(TAG,
              "Error Building UART Message: payload_len, %d, sendbuffer_size: "
@@ -173,8 +179,7 @@ void app_main(void) {
   wifi_config_t wifi_config = {
       .sta =
           {
-              .channel = 1, // Kanal 1, stelle sicher, dass alle Geräte
-                            // denselben Kanal verwenden
+              .channel = 1,
           },
   };
   ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA));
@@ -188,7 +193,7 @@ void app_main(void) {
     ESP_ERROR_CHECK(esp_now_register_recv_cb(client_receive_callback));
   }
 
-  init_com(&clientList, 1);
+  ret = init_com(&clientList, 1);
   if (ret < 0) {
     ESP_LOGE(TAG, "Could not Init ESP NOW Communication!");
   }
@@ -289,7 +294,7 @@ void app_main(void) {
     // NULL);
   } else {
     ESP_LOGI(TAG, "Started in Slavemode");
-    xTaskCreate(client_data_sending_task, "ClientDataSending", 4096, NULL, 1,
-                NULL);
+    // xTaskCreate(client_data_sending_task, "ClientDataSending", 4096, NULL, 1,
+    //             NULL);
   }
 }
diff --git a/main/ota_update.c b/main/ota_update.c
new file mode 100644
index 0000000..38b7bdf
--- /dev/null
+++ b/main/ota_update.c
@@ -0,0 +1,50 @@
+#include "ota_update.h"
+#include "esp_log.h"
+#include "message_handler.h"
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+
+static uint8_t updateBuffer[4000];
+static const char *TAG = "ALOX - OTA";
+
+void start_uart_update(uint8_t msgid, const uint8_t *payload,
+                       size_t payload_len, uint8_t *send_payload_buffer,
+                       size_t send_payload_buffer_size, uint8_t *send_buffer,
+                       size_t send_buffer_size) {
+  ESP_LOGI(TAG, "OTA Update Uart Command");
+
+  // prepare for writing new partition with ota api
+  // will get 200 bytes each uart message
+  // fill update buffer
+  // write update buffer complete
+
+  /*int len = build_message(0x02, send_payload_buffer, needed_buffer_size,
+                          send_buffer, send_buffer_size);
+  if (len < 0) {
+    ESP_LOGE(TAG,
+             "Error Building UART Message: payload_len, %d, sendbuffer_size: "
+             "%d, mes_len(error): %d",
+             payload_len, send_buffer_size, len);
+    return;
+  }
+  uart_write_bytes(MASTER_UART, send_buffer, len - 1);*/
+}
+
+void payload_uart_update(uint8_t msgid, const uint8_t *payload,
+                         size_t payload_len, uint8_t *send_payload_buffer,
+                         size_t send_payload_buffer_size, uint8_t *send_buffer,
+                         size_t send_buffer_size) {
+  ESP_LOGI(TAG, "OTA Update Uart Command");
+}
+
+void end_uart_update(uint8_t msgid, const uint8_t *payload, size_t payload_len,
+                     uint8_t *send_payload_buffer,
+                     size_t send_payload_buffer_size, uint8_t *send_buffer,
+                     size_t send_buffer_size) {
+  ESP_LOGI(TAG, "OTA Update Uart Command");
+}
+
+void init_ota() {
+  RegisterCallback(uint8_t msgid, RegisterFunctionCallback callback);
+}
diff --git a/main/ota_update.h b/main/ota_update.h
new file mode 100644
index 0000000..2792b78
--- /dev/null
+++ b/main/ota_update.h
@@ -0,0 +1,4 @@
+#ifndef OTA_UPDATE_H
+#define OTA_UPDATE_H
+
+#endif
diff --git a/main/uart_msg_ids.h b/main/uart_msg_ids.h
new file mode 100644
index 0000000..9e90345
--- /dev/null
+++ b/main/uart_msg_ids.h
@@ -0,0 +1,17 @@
+#ifndef UART_MSG_IDS_H
+#define UART_MSG_IDS_H
+
+enum UART_MSG_IDS {
+  // MISC
+  UART_ECHO = 0x01,
+  UART_VERSION = 0x02,
+  UART_CLIENT_INFO = 0x03,
+
+  // OTA
+  UART_OTA_START = 0x10,
+  UART_OTA_PAYLOAD = 0x11,
+  UART_OTA_END = 0x12,
+  UART_OTA_STATUS = 0x13,
+};
+
+#endif