Arduino-esp32: SSID is hide after set esp_wifi_set_protocol( WIFI_IF_AP, WIFI_PROTOCOL_LR )

[NickChungVietNam]

Hardware :
ESP32-WROOM.
Ide :1.8.2.

Hi Sir.
After try this code, my ESP32 hided SSID on AP forever ( on any other sketch). I try again with my second esp32 , the result is both 2 esp32 is hide SSID forever. My esp32 still work well in STA mode, but right now i can not use it on AP application because STA dont 'see' the AP. How can i fix to show SSID again?
Please HELP ME !
This is the code 'killed' my esp32 : (dont try to fash your ESP this code)

#include <Arduino.h>
#include <WiFi.h>
#include <WiFiUdp.h>

#include <esp_wifi.h>

const char *ssid ="ssid";
char *pass="123456789";
WiFiUDP udp;

const char *toStr( wl_status_t status ) {
switch( status ) {
case WL_NO_SHIELD: return "No shield";
case WL_IDLE_STATUS: return "Idle status";
case WL_NO_SSID_AVAIL: return "No SSID avail";
case WL_SCAN_COMPLETED: return "Scan compleded";
case WL_CONNECTED: return "Connected";
case WL_CONNECT_FAILED: return "Failed";
case WL_CONNECTION_LOST: return "Connection lost";
case WL_DISCONNECTED: return "Disconnected";
}
return "Unknown";
}

void setupAp() {
WiFi.begin();
delay( 500 ); // If not used, somethimes following command fails
WiFi.mode( WIFI_AP );
ESP_ERROR_CHECK( esp_wifi_set_protocol( WIFI_IF_AP, WIFI_PROTOCOL_LR ) );

Serial.println( WiFi.softAP( ssid, pass ) );
Serial.println( WiFi.softAPIP() );
delay( 1000 );
}

void setup() {
Serial.begin( 115200 );
Serial.println( "Master" );
setupAp();
udp.begin( 8888 );
}

void loop() {
udp.beginPacket( { 192, 168, 4, 255 }, 8888 );
udp.write( 'b' );

if ( !udp.endPacket() )
    ESP.restart(); // When the connection is bad, the TCP stack refuses to work
delay( 1000 );
}

[beegee-tokyo]

I think your problem is that you set your WiFi to WIFI_PROTOCOL_LR.
While in Long Range mode, the WiFi cannot be seen by "normal" WiFi devices. Try to erase NVS partition of your ESP32 and / or flash a firmware that does NOT set the WiFi into Long Range mode. I was playing around with Long Range mode before and could get back to normal WiFi mode.
For erasing NVS partition check out WiFi connection problem - NVS corrupted for a code snippet how to erase the NVS partition.

[NickChungVietNam]

*beegee-tokyo * You are my god. Thank you so much.
I copy the code fix on this page : https://desire.giesecke.tk/index.php/2018/02/26/wifi-connection-problem-nvs-corrupted/
WiFi connection problem – NVS corrupted
If you have WiFi connection problems where WiFi.status() always returns WL_NO_SSID_AVAIL even you are sure that the AP is available and working, it might be that the NVS storage has been corrupted.

The NVS storage is the place where esp-idf stores the WiFi credentials. See issue wifi connection problem on Arduino-esp32. To check if your NVS storage is corrupted you can use ESP32-Show_nvs_keys provided by stickbreaker.

If your NVS storage is corrupted you can use the following code snippet to wipe all stored NVS keys. Attention, you will loose your previously stored WiFi credentials when using this.
This the code i used.
```` ruby

include

include

void clearNVS() {
int err;
err=nvs_flash_init();
Serial.println("nvs_flash_init: " + err);
err=nvs_flash_erase();
Serial.println("nvs_flash_erase: " + err);
}
*beegee-tokyo * You are my god.
void setup() {
// put your setup code here, to run once:
Serial.begin(115200);
clearNVS();
}

void loop() {
// put your main code here, to run repeatedly:

}
````

[beegee-tokyo]

Happy I could help.