ESP8266 watchdog reset when using WiFi

I'm trying to use WiFi on a ESP8266EX based board (XTVTX WEMOS D1 Mini Pro).

The sketch is really simple.

#include <ESP8266WiFi.h>

void setup() {
  Serial.begin(9600);

  WiFi.begin("<ssid>", "<password>");
}

void loop() {
  if ( WiFi.status() == WL_CONNECTED)
  {
    Serial.println("Connected");
  }
  else 
  {
    Serial.println("Not Connected");
  }

  yield();
}

The board keeps rebooting for a watchdog reset (source: https://arduino-esp8266.readthedocs.io/en/latest/boards.html#rst-cause).

After a few seconds a fatal exception is raised (28 = LoadProhibitedCause - source: https://arduino-esp8266.readthedocs.io/en/latest/exception_causes.html#exception-causes-exccause).

Here it is the log that shows the issue.

 ets Jan  8 2013,rst cause:4, boot mode:(3,6)

wdt reset
load 0x4010f000, len 3424, room 16 
tail 0
chksum 0x2e
load 0x3fff20b8, len 40, room 8 
tail 0
chksum 0x2b
csum 0x2b
v00044b80
~ld
sp 0x3fffe9d0 
epc1=0x40204d1a, epc2=0x00000000, epc3=0x00000000, excvaddr=0x04000102, depc=0x00000000
Fatal exception (28): 
epc1=0x40001800, epc2=0x00000000, epc3=0x00000000, excvaddr=0x00007ff0, depc=0x00000000
Fatal exception (28): 
epc1=0x40001800, epc2=0x00000000, epc3=0x00000000, excvaddr=0x00007ff0, depc=0x00000000
Fatal exception (28): 
epc1=0x40001800, epc2=0x00000000, epc3=0x00000000, excvaddr=0x00007ff0, depc=0x00000000
Fatal exception (28): 
epc1=0x40001800, epc2=0x00000000, epc3=0x00000000, excvaddr=0x00007ff0, depc=0x00000000
Fatal exception (28): 
epc1=0x40001800, epc2=0x00000000, epc3=0x00000000, excvaddr=0x00007ff0, depc=0x00000000
Fatal exception (28): 
epc1=0x40001800, epc2=0x00000000, epc3=0x00000000, excvaddr=0x00007ff0, depc=0x00000000
Fatal exception (28): 
epc1=0x40001800, epc2=0x00000000, epc3=0x00000000, excvaddr=0x00007ff0, depc=0x00000000
Fatal exception (28): 
epc1=0x40001800, epc2=0x00000000, epc3=0x00000000, excvaddr=0x00007ff0, depc=0x00000000
[...]

My setup:

• Power: USB 3.0 powered hub (5V 500mA)
• IDE: Arduino IDE v2.0.4 on Linux
• Library: esp8266 from ESP8266 Community v3.1.1 (tried also 3.1.0 and 3.0.2)
• Programmer settings:
  • Board: Generic ESP8266 Module
  • Upload speed: 115200
  • Crystal Frequency: 26MHz
  • Flash Size: 4MB (FS: none OTA: 1MB)
  • CPU Frequency: 80MHz
  • MMU: 32KB cache + 32 KB IRAM
  • lwip variant: v2 lower memory
  • NONOS SDK: nonos-sdk 2.2.1+100
  • Erase flash: all flash content
  • Flash frequency: 40MHz

Every other sketch which does not involve the use of WiFi is working without issues.

This sketch works fine on the AzDelivery ESP8266MOD 12-F board which is very similar.

The board is new and I've seen the WiFi working for a few seconds before entering in the boot loop.

Other people with the same behavior were using #include <WiFi.h> instead of #include <ESP8266WiFi.h>, so this is not my case.

I can't understand what is the problem. Has anyone faced this problem before and found a solution?

Thank you for your time.

As suggested by @Juraj (see comments below the question) the problem is the power consumption of this board.

I've modified the sketch in this way:

#include <ESP8266WiFi.h>

void setup() {
  Serial.begin(9600);

  // >>>>>
  // set the maximum tx power (Values range from 0 to 20.5 [dBm] inclusive)
  WiFi.setOutputPower(19.25);
  // <<<<<

  WiFi.begin("<ssid>", "<password>");
}

void loop() {
  if ( WiFi.status() == WL_CONNECTED)
  {
    Serial.println("Connected");
  }
  else 
  {
    Serial.println("Not Connected");
  }

  yield();
}

When values higher than 19.25 are set, the board resets every time a connection with the AP is established.

See the documentation here https://arduino-esp8266.readthedocs.io/en/latest/esp8266wifi/generic-class.html#setoutputpower.

Thanks to @Juraj for the quick support!

Try adding a while loop in setup() to wait until the WiFi connection is established

#include <ESP8266WiFi.h>
void setup() {
  Serial.begin(9600);
  WiFi.begin("<ssid>", "<password>");
  while (WiFi.status() != WL_CONNECTED);
  delay(1000);
}

void loop() {
  if (WiFi.status() == WL_CONNECTED) {
    Serial.println("Connected");
  } else {
    Serial.println("Not connected");
  }
  delay(1000);
}