I am trying to set up a Huzzah ESP8266 and can not get it to work. I have scoured the internet for help and to no avail. I have the board loaded with a baud rate of 115200 and am transmitting at 80 MHz. When I try and upload the sketch it successfully uploads and after a second or two it sends me this error.

Sketch uses 222,209 bytes (21%) of program storage space. Maximum is 1,044,464 bytes. Global variables use 31,576 bytes (38%) of dynamic memory, leaving 50,344 bytes for local variables. Maximum is 81,920 bytes.

warning: espcomm_sync failed

error: espcomm_open failed

error: espcomm_upload_mem failed

error: espcomm_upload_mem failed

Here is my code:

 void setup() {
pinMode(LED_BUILTIN, OUTPUT);     // Initialize the LED_BUILTIN pin as an output

// the loop function runs over and over again forever
 void loop() {
digitalWrite(LED_BUILTIN, LOW);   // Turn the LED on (Note that LOW is the    voltage level
                                // but actually the LED is on; this is     because 
                                // it is acive low on the ESP-01)
delay(1000);                      // Wait for a second
digitalWrite(LED_BUILTIN, HIGH);  // Turn the LED off by making the voltage HIGH
delay(2000);                      // Wait for two seconds (to demonstrate the active low LED)

Does anyone know what I'm doing wrong or can anyone help me out.

  • Did you select the port of your ESP8266 in the Tools > Port menu? Please select File > Preferences > Show verbose output during > upload, upload the sketch, and then update the error message in your question with the full verbose output.
    – per1234
    Oct 2, 2016 at 10:31
  • espcomm error messages usually mean that your sketch is -not- uploaded correctly. Are you sure you selected "Adafruit HUZZAH ESP8266" in the arduino IDE? It should be in the list.
    – bluemind
    Oct 3, 2016 at 13:36
  • Also, does the HUZZAH actually have a usb to serial chip on the board, or do you need an external one? If so whichone are you using? Some FTDI? I can't check myself atm., behind a firewall :)
    – bluemind
    Oct 3, 2016 at 13:39
  • Have you contacted your seller/supplier? Adafruit actually has very good support and they sure know their hardware and possible faults.
    – aaa
    Feb 14, 2018 at 22:38

2 Answers 2


If you´re working with a development board, they (usually) come with tow buttons: Reset and Flash. If this is the case before start to upload your code you must press the Flash button, this error is common when the Flash button it's not pressed.

If you're working with an ESP8266-01 (this is the "naked" esp8266) you must read this tutorials: GreatScott vid on youtube, and for the connections: a good Hackster.io tutorial.

Hope you can make it run!!!


When using a serial cable (4 wires, only works on windows), you need to press the 2 buttons in the sequence described here (https://learn.adafruit.com/adafruit-huzzah-esp8266-breakout/using-arduino-ide): gpio0 down, reset down, reset up, gpio0 up. The red led should be dim now. This means the huzzah is ready to bootload.

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