I can't figure out how to flash the firmware found on http://www.electrodragon.com/w/ESP8266_AT-Command_firmware. I am using ESP8266 Download tool v3.4.4. When I am adding a firmware in download path it goes on till a fixed percentage (77 or 99..mostly) and gives the error Invalid head of packet, FAST FLASHING ERROR. One more thing is that the tutorials I am using to do this have many download path entries filled in the download tool while mine are just blank. It says upload the combined file to 0x0000. I tried uploading V1.54... file's content (both files) but still got the similar error.

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So anyone could just guide me through this as I am a complete newb into this. Please mention any other information needed in comments.


  1. I am pretty sure the power supply is adequate as I have been using esp8266 with the old firmware smoothly. I have also connected a 200uF capacitor b/w gnd and vcc(3.3v from FTDI).
  2. I have double checked the connections.(Yes, GPIO0 is grounded).
  3. I flashed an earlier version successfully ai-thinker-v1.1.1.bin but when I connected it to arduino IDE serial monitor it started giving unending gibberish text :P.
  • 1
    What is the flash size of your ESP? Commented Mar 11, 2017 at 9:25
  • Not sure, but it says 32 bit MCU Commented Mar 11, 2017 at 9:34
  • I was silly it is on the picture. 8Mbit. Commented Mar 11, 2017 at 12:36
  • I was having the same problem and just changed the BAUD rate deoim 115200 to 230400 and it flashed the firmware without errors. Commented Jun 26, 2017 at 20:51
  • you do realise you've set two files to load to the same address, right? Commented Feb 21, 2018 at 0:16

1 Answer 1


Configuration that worked for me

Okay found the solution.

  1. Firstly I think the detected info block tells the flash size. In Snap it could be seen as 8MBit.
  2. The 1.54 version of the firmware has two files, one for 8Mbit and the other for 32Mbit.
  3. I went for 8Mbit and checked both SpiAutoSet and DoNotChgBin, and volla. It was succesful this time.
  4. I set the baudrate to maximum (1500000) not sure though if it's necessary.

PS: Please help improve the answer by mentioning any important information I need to mention in the answer or If anything is wrong.

  • 1
    In effect, @Bence was right then. I don't know the toolchain, is there anything you can edit in your answer to make it more useful for someone else with a similar problem - such as a screenshot of where you see the flash size? Commented Mar 11, 2017 at 10:25
  • Added it @SeanHoulihane Commented Mar 11, 2017 at 10:35
  • I believe baudrate is usually 115200, not sure though. Commented Mar 11, 2017 at 15:46

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