Yes Rudi !
You're right.
Many thanks again.

many thanks rudi,
but I using Arduino IDE, and with
etharp_get_entry(index_entry, &ip, &netif, &ethaddr)
ARP table is empty, but ethernet is working.

LE: it's working ! I have entrys in ARP table.
But is need to I ping esp32 from network.
I thought that MAC router appears in the ARP table after the ...

or, it's possible to read arp table ?

Hi,
I used:
https://github.com/espressif/arduino-esp32/tree/master/libraries/Update/examples
for http firmware udate.
"OTA done!"
"Update successfully completed. Rebooting."
after ESP.restart() line, ESP rebooting Ok with the new firmware.

But after power off/on the old firmware is executed ...

I almost found the answer.
I launched "esptool erase_flash" and the Wifi works ok now!
And I repeated the experiment several times.
The line that blocking WiFi is:
esp_wifi_set_protocol (ESP_IF_WIFI_STA, WIFI_PROTOCOL_LR);
This "WIFI_PROTOCOL_LR" is the problem. But ESP-Now works normally in tests ...

I did some ESP-Now tests with two ESP WROOM-32. And the communication went well.
After these tests, I can no longer use classic WiFi.
None of the modules can connect to an AP or set as an AP.
Strange, I can see the APs in the area with WiFi scanning using these ESPs.
But when I try to connect I get ...

I think it is possible to receive or send 9 bytes using the parity bit.
SERIAL_8E1
But is it possible to set the parity bit manually on ESP UART ?
(parity = Mark / Space)

ESP_Sprite many, many thanks !

Of corse, overflow

len=512;
buf = (char *)malloc(len);
..
buf[len]=0x00; <--
...
free(buf); <-- that is the line reported by tools EspExceptionDecoder (interesting).

Hi,
How can I find where in the source program is the line that generates the error?

CORRUPT HEAP: Bad tail at 0x3ffb8695. Expected 0xbaad5678 got 0xbaad560d
abort() was called at PC 0x400832fd on core 1
Backtrace: 0x40084e80:0x3ffb1af0 ...
Rebooting...

OnDataSent , "status" parameter == ESP_NOW_SEND_SUCCESS means the pair answered with ACK.