Sending a request esp32-bluetooth - make a call from my phone

1. Identify the MAC address of the device that the ESP32 first connected to. 2. Save this MAC address to non-volatile memory (e.g., the ESP32's flash memory) so that it survives reboots. 3. Compare the MAC address on subsequent connection attempts so that the ESP32 only connects to the device with the saved MAC address. Pls help

What is your objective? To save a device MAC?

so that next time it will connect only to the last device

That's in the text above! Please read your question again.