I've connected ESP8266 to Arduino UNO. After a getting a huge trouble I successfully managed to run some AT commands. I have also tested AP mode.

Then I got some trouble with software serial communication with Arduino and decided to change baud-rate to 9600 (previously it was 115200).

I used AT+IPR=9600 command to change it.

After that blue led of esp stays on and not taking AT commands any more, but output some gibberish to serial monitor with few ascii text like below:

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

wdt reset
load 0x40100000, len 1396, room 16 
tail 4
chksum 0x89
load 0x3ffe8000, len 776, room 4 
tail 4
chksum 0xe8
load 0x3ffe8308, len 540, room 4 
tail 8
chksum 0xc0
csum 0xc0

2nd boot version : 1.4(b1)
SPI Speed      : 40MHz
SPI Mode       : DIO
SPI Flash Size & Map: 8Mbit(512KB+512KB)
jump to run user1 @ 1000

Note: I know it consumes a lot power tried external 3.3V power supply and voltage divider for rx pin.

Any help would be appreciated.

  • 1
    I have exactly the same after running that command "AT+IPR=9600". Any update on how you fixed this?
    – rabs
    Commented Mar 27, 2016 at 9:37
  • I fixed this by updating its firmware @rabs
    – palash
    Commented Mar 30, 2016 at 17:22
  • Here I posted what I did to solve this error. I hope somebody finds it helpful: bbs.espressif.com/viewtopic.php?t=4597#p15844
    – grange
    Commented Sep 19, 2017 at 10:22

1 Answer 1


If you have too, you can find the firmware for the ESP8266 here and re-flash it.

There's some good info here about the instruction set.

With respect to your issue of the blue (traffic) light staying on, I can't imagine that the baud command would have caused an issue. Perhaps you need to double check your circuit and make sure that the Rx pin of the ESP8266 is not being held high.

What happens with only 3.3V and GND connected to the ESP8266?

Also the output you're getting is similar to the output from “AT+GMR”. Are you sending it that in a loop by chance?

  • If I only connect 3.3V and GND then only red led stays on (as usual). But if I pull CH_PD to high (connect to 3.3V using a 10K resistor) then blue led stays on. @James
    – palash
    Commented Jan 27, 2016 at 16:58

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