ESP32S not working Serial / UART

Good day! Please help. ESP32S not working Serial / UART

Serial2.setup(9600, { tx: D4, rx: D15 });
Serial2.on('data', function(data) {
    console.log('Serial2: ', data);
});
//Serial2.print('Hello UART2');
//Serial2.setup(115200);
var  wifi = require("Wifi");
function onInit() {
  print("STRAT>>>1");
   wifi.connect("INGRIFABCP", {password: "B73vFeX6se2"}, function() {
        console.log("connected!");
        console.log(wifi.getIP().ip);
     wifi.save();
   });
}
save();

| |_ ___ ___ _ ||___ ___
| |_ -| . | _| | | | | . |
||| || |_|||_|_|

      |_| http://espruino.com

1v94 Copyright 2016 G.Williams
Espruino is Open Source. Our work is supported
only by sales of official boards and donations:
http://espruino.com/Donate

E (123248) uart: uart_read_bytes(857): uart driver error
E (124248) uart: uart_read_bytes(857): uart driver error
=undefined
Erasing Flash..................
Writing......
Compressed 80000 bytes to 3715
Checking...
Done!
Running onInit()...
STRAT>>>1
ERROR: Prompt not detected - upload failed. Trying to recover...
echo(1)
=undefined
Serial2.print('Hello UART2');
=undefined

Does it work if you get rid of the oninit and save ?

Just upload the code in the simple form and send something to serial2

Hi @Alexander,

if you use save() in upload code than wrap it with setTimeout(save,2000) to be sure that code is completely upload before running save().