Fatal error occurred failed to connect to esp32 timed out waiting for packet header

I tried to flash an ESP32 but I didn’t succeed, I tried with esptool.py and Arduino IDE. I tried to press the boot button and reset but it didn’t work. Here is the error:

A fatal error occurred: Failed to connect to ESP32: Timed out waiting for packet header

If using the Arduino IDE, try lowering the upload speed (Tools/Upload Speed). Lowering mine from 921600 to 460800 did the trick.

First ensure that you are in download mode:

• Start the serial monitor and set the speed (mine is 115200).
• While pressing the «boot» button, press and release the «en» button (your buttons may be labeled differently).
• You should see something like this on the serial monitor:
  waiting for download
• Now start the upload

My development machine, a 2013 iMac is connected via USB to the USB-c port on my ESP32 Dev Module. Apparently the iMac’s USB or ESP32 board’s USB cannot keep up at the 921600 upload speed.

answered Nov 30, 2022 at 23:13

DISCLAIMER! May not be correct answer but may help to save time for someone.

Quick answer if you do not want read my experience: Disconnect all wires from pins and try uploading again! It may help.

I came across with the same error and could not figure it out. I first thought that something is wrong with the code, because it happened after I edited working code while figuring out where to connect what pin 😀. I also wasn’t able to upload simple HelloWorld after it happened with connected wires. But then I disconnected all my wires from the board and the upload works fine.

I can not figure out the WHY factor but I think it must had been the input/data pin I was using, in my case D13. I have the DevKit with fewer pins. Maybe someone can comment why connected pins may make the error come up?

answered Apr 7, 2022 at 19:27

answered Apr 8, 2022 at 9:44

Try to do this one after the other

1. Press the boot button when press uploading button until it write the code.
2. Try disconnect esp32 from the board/header/pcb that you are using right at the time.
3. Disconnect any other connection that your esp32 might have.
4. Do not connect to anything even your hand if possible.
5. Try put it in something that doesnt have a moist surface. look pic number 3.

MY CASES(30 pin version):

Case 1: I dont know why. I was connecting the pin to a female header it doesnt work and sometimes it just work like that. look pic number 1.

Case 2: when Im holding esp32 on my hand sometimes it wont work then i put it on my table and another time it doing well.

Case 3: pressing boot button when uploading it helped sometimes, and the other time it just work like it should.

Case 4: when it connected to pcb its simply just wont work, but when disconnected boom it work like nothing ever happen. look pic number 2.

Maybe just maybe something with capacitive or something like that (just assuming because number Case 1). hope that will help you out.

pic 1pic 2pic 3

answered May 20, 2022 at 17:22

With Arduino IDE
Make sure the Com port is selected under Tools menu. My experience with ESP32 is Com 5.
If it is not available as an option, try changing USB ports and/or re-select Tools — Board — ESP32 dev module.

Watch the «Compiling Sketch» window.
Press the «Boot» button as soon as you get the red message «Serial port Com 5» You can release the button as soon as it starts to upload.
If this doesn’t work,try plugging into another USB port.

The Reset button only resets the uploaded sketch to re-initialise and has nothing to do with the uploading.

answered Jan 24, 2022 at 17:11

answered Oct 27, 2022 at 15:14

answered Dec 3, 2022 at 19:26

answered Jan 26 at 9:21

Just download the drivers x)

CP210x: CP210x USB to UART Bridge VCP Drivers

FTDI: FTDI Virtual COM Port Drivers

answered Sep 29, 2022 at 14:10

Hello !

After the yesterday’s fiasco, today I’ve been trying to upload any sketch to a new, out-of-the-box ESP32-EVB. But it doesn’t work.

I keep getting:
A fatal error occurred: Failed to connect to ESP32: Timed out waiting for packet header

What’s happening ? Maybe the ESP32-Wroom-32 is burned out, but this one is new, never touched.

The ESP32-EVB is only connected to the PC via a USB Cable.
These are the Arduino IDE settings:
https://i.postimg.cc/J4DR3jrC/Screensho … -14-31.png

Have you tried holding down the EN button during sketch upload?

I found some but not all ESP’s require the EN button to be held down before and until the upload has started. That is till, I added a powered USB hub. Once I added in a powered USB hub the need for sometimes holding down the EN button during a sketch upload went away. Also, have you looked at the basic schematic for the ESP module? You will notice that there is a direct connection from the 5V line to the USB port and your computer. If something happens to your ESP32, the happening can be fed back into your computer if directly connected; another reason to have that added layer of protection of a powered USB hub.

idahowalker wrote: ↑

Tue Apr 02, 2019 12:01 pm

Have you tried holding down the EN button during sketch upload?

I found some but not all ESP’s require the EN button to be held down before and until the upload has started. That is till, I added a powered USB hub. Once I added in a powered USB hub the need for sometimes holding down the EN button during a sketch upload went away. Also, have you looked at the basic schematic for the ESP module? You will notice that there is a direct connection from the 5V line to the USB port and your computer. If something happens to your ESP32, the happening can be fed back into your computer if directly connected; another reason to have that added layer of protection of a powered USB hub.

I’ve always pressed the EN Button on the ESP32 boards. With the ESP32-Wroom-32 and now with the ESP32-EVB.

With the EVB the trick seems to be to keep holding down the BUT1, then press on RST1, then release BUT1 and it starts uploading. This sometimes works on Arduino IDE. On PlatformIO IDE I couldn’t figure how to upload code.

You’re saying that I can harm the PC if I connect the ESP directly to it via a USB Cable ? I never thought of that.

GeorgeFlorian1 wrote: ↑

Tue Apr 02, 2019 1:18 pm

You’re saying that I can harm the PC if I connect the ESP directly to it via a USB Cable ? I never thought of that.

I have experienced the 5V regulator supplying the ESP32 5V, deciding to put out a higher voltage, than 5V. If you look at the ESP32 schematic, you’ll see that the 5V from the USB plug is directly tied to the ESP5V supply line. So, when the 5V regulator decided to put more then 5V onto the 5V line, the ESP32 died, the >5V was felt on my pc’s USB 5V line. Which does wonders for the operation of the PC. My case, I feel I got lucky and will not, from that point on, connect any uController directly to my PC. Instead all uController connections to my PC are through a powered hub. I call it wearing a rubber.

idahowalker wrote: ↑

Tue Apr 02, 2019 7:41 pm

GeorgeFlorian1 wrote: ↑

Tue Apr 02, 2019 1:18 pm

You’re saying that I can harm the PC if I connect the ESP directly to it via a USB Cable ? I never thought of that.

I have experienced the 5V regulator supplying the ESP32 5V, deciding to put out a higher voltage, than 5V. If you look at the ESP32 schematic, you’ll see that the 5V from the USB plug is directly tied to the ESP5V supply line. So, when the 5V regulator decided to put more then 5V onto the 5V line, the ESP32 died, the >5V was felt on my pc’s USB 5V line. Which does wonders for the operation of the PC. My case, I feel I got lucky and will not, from that point on, connect any uController directly to my PC. Instead all uController connections to my PC are through a powered hub. I call it wearing a rubber.

https://i.postimg.cc/ZnxrcQMb/esp-pin.jpg

Measuring the Voltage Regulator that’s on the ESP I noticed that between pin 1 and 3 there are 4.35V when the ESP is connected to the PC using a USB Cable. Is that normal ?

GeorgeFlorian1 wrote: ↑

Tue Apr 02, 2019 11:15 am

Hello !

After the yesterday’s fiasco, today I’ve been trying to upload any sketch to a new, out-of-the-box ESP32-EVB. But it doesn’t work.

I keep getting:
A fatal error occurred: Failed to connect to ESP32: Timed out waiting for packet header

What’s happening ? Maybe the ESP32-Wroom-32 is burned out, but this one is new, never touched.

The ESP32-EVB is only connected to the PC via a USB Cable.
These are the Arduino IDE settings:
https://i.postimg.cc/J4DR3jrC/Screensho … -14-31.png

By the end of compile connect GPIO0 to GND and keep it till end of upload.
See if you are able to upload. After upload you remove this connection. You can use a jumper wire.

The Boot button is 0.

I’d suggest opening your serial monitor. Then hold down Boot, don’t be shy, you can’t do it too early and there’s no harm in holding it longer than necessary. Give the reset button a good click and you should see some output saying that it’s in download mode.

Make sure that works before attempting to program it. Then close serial.

When you program it, it will probably try to do this automatically. You can give it a helping hand by holding down the Boot button all-the-while to make sure that it boots into download mode (it’s ok to release once it starts uploading). If it doesn’t reset automatically (ie. if it doesn’t start uploading), click the reset button to do it yourself, while still holding down Boot of course.

That should be fairly fool-proof.

boarchuz wrote: ↑

Tue Apr 16, 2019 8:42 am

The Boot button is 0.

I’d suggest opening your serial monitor. Then hold down Boot, don’t be shy, you can’t do it too early and there’s no harm in holding it longer than necessary. Give the reset button a good click and you should see some output saying that it’s in download mode.

Make sure that works before attempting to program it. Then close serial.

When you program it, it will probably try to do this automatically. You can give it a helping hand by holding down the Boot button all-the-while to make sure that it boots into download mode (it’s ok to release once it starts uploading). If it doesn’t reset automatically (ie. if it doesn’t start uploading), click the reset button to do it yourself, while still holding down Boot of course.

That should be fairly fool-proof.

Tried this a long time ago. I got nothing and still getting nothing. I really think the ESP is busted.

I’ve always had to press on BOOT button to be able to upload code the ESP. Now I got a new Wrover-B DevKitV4 and I still have to keep BOOT pressed.