I use ESP8266-12 with an Arduino Uno as a USB-serial adapter.

When I upload any sketch to the ESP8266 it works fine until I reset the ESP8266.

uint32_t realSize = ESP.getFlashChipRealSize();
uint32_t ideSize = ESP.getFlashChipSize();
FlashMode_t ideMode = ESP.getFlashChipMode();

Serial.printf("Flash real id:   %08X\n", ESP.getFlashChipId());
Serial.printf("Flash real size: %u\n\n", realSize);

Serial.printf("Flash ide  size: %u\n", ideSize);
Serial.printf("Flash ide speed: %u\n", ESP.getFlashChipSpeed());
Serial.printf("Flash ide mode:  %s\n", (ideMode == FM_QIO ? "QIO" : ideMode == FM_QOUT ? "QOUT" : ideMode == FM_DIO ? "DIO" : ideMode == FM_DOUT ? "DOUT" : "UNKNOWN"));

if(ideSize != realSize) {
    Serial.println("Flash Chip configuration wrong!\n");
} else {
    Serial.println("Flash Chip configuration ok.\n");


If I ground reset button, garbage values are being shown.

Connections details:

EN - 3.3V of Uno
VCC - 3.3V of Uno
RST - GND Of Uno(If needed)
TX - TX of Uno
RX - RX of Uno
GPO15 - GND of Uno
GPO01 - GND of Uno
GND - GND of Uno

  • 1
    Possible duplicate of ESP8266 + Arduino Uno: Can't send AT Commands
    – gone
    Aug 16, 2017 at 13:56
  • 2
    Please edit your question to include a Minimal, Complete, and Verifiable example of code, not just snippets.
    – user31481
    Nov 4, 2017 at 10:28

1 Answer 1


Espressif says it can not be disabled.

Ref.: https://github.com/esp8266/Arduino/issues/3047

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