I have an ESP8266-01. I followed the instructions on this


exactly. When I start the firmware update the TX and RX pins blink rapidly along with the blue light on the ESP.

Then the terminal spits out "chip sync error" and disconnects.

I would like this to work because buying a ftdi cable isn't an option right now.

  • 1
    This error occurs due to a mismatch in Baud rates. So I suggest you try different baud rates, specifically 9600 and 115200 as these seem to be the most common....Gd Luck!!
    – Mero55
    Aug 10, 2016 at 18:23
  • I have copy-paste @Mero55's comment as an answer so OP can accept it and close the question.
    – user31481
    Oct 28, 2017 at 19:51
  • Problem is...... In the ESP8266 Flash_Download_Tool_v3.6.1 The lowest setting available is 115200 baud
    – Randy
    Nov 4, 2017 at 20:35
  • It's actually likely that the ESP isn't in flashing mode.- you did follow the points under Flash it! to the letter, right Feb 4, 2018 at 0:00

2 Answers 2


I run the same problem too and took me countless hours to figure this error out. The problem seems the Baud rate starts at 115200 while the COM port is set to 9600. What I did is I checked the Device Manager and find the COM port, right clicked to properties and to the Port Settings Tab, I changed the Baud Rate to 115200 and flash the firmware again. And it works!


just after compilaion starts in the arduino ide , press and hold the flash button and then press the reset button , now release the reset button and finally release the flash button, this is how the esp goes into flash mode.this will work

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