RAK4630 BLE issues

hello
I am using RAK4630.
I have succeeded in LoRa P2P communication.
I want to communicate with my microcontroller and android application via BLE.
However, I checked all AT commands, but I do not see any commands for sending/receiving data through BLE.
Does anyone know anything about this issue?

Welcome to the forum @LeeJongJin

BLE is not supported through AT commands. To use BLE you need to write a custom application based on the RUI3 API.

RUI3-BLE-Examples

If I write a custom application, will the existing firmware disappear? Can I use existing AT commands?

If you write a custom firmware with RUI3 API you keep all AT commands and the complete LoRa P2P and LoRaWAN support.
You write your application on top of all of that.

I tried to create and build a user application via Arduino as in the documentation, but it fails.
I tried it via USB on the RAK4630 but it doesn’t upload. The same goes for UART1.

I was successful in building and uploading custom firmware.
However, it still cannot communicate via UART with the microcontroller.
In Arduino IDE, Seril is the USB port of RAK4630.
I connected the microcontroller through UART1 of RAK4630.
The microcontroller achieved LoRa communication via UART1.
However, I cannot communicate with the microcontroller through Serial1 or Serial2 in Arduino IDE.
Which Serial ports can communicate with the microcontroller?

The RAK4630 can only be flashed through it’s USB port (built-in). USB port is Serial in Arduino IDE
Serial1 is UART1 Serial2 is UART2

Here is the code I used

In this way, data sent from Android via BLE can only be received via Serial (i.e. USB).
Did I do something wrong?