ESP32 Forum

Hi everyone,
I’m currently using the ESP32-S3-DEVKITM-1U board with ESP-IDF v5.5.1-dirty, and I’m trying to run the basic blink LED example. However, I keep running into the following error during flashing:

A fatal error occurred: Failed to connect to ESP32: No serial data received.
For troubleshooting steps visit: https://docs.espressif.com/projects/esp ... oting.html
CMake Error at run_serial_tool.cmake:67 (message):
C:/Esp/Espressif/python_env/idf5.5_py3.11_env/Scripts/python.exe;;C:/Esp/Espressif/frameworks/esp-idf-v5.5.1/components/esptool_py/esptool/esptool.py;--chip;esp32 failed.
ninja: build stopped: subcommand failed.

I’ve already tried several solutions mentioned in the Espressif forums and on Reddit — including checking the COM port, using different USB cables, pressing and holding BOOT while pressing RESET, and even reinstalling the ESP-IDF environment — but none of these worked.

In cases where I hold BOOT while pressing RESET, or disconnect the ESP board and reconnect it while holding BOOT, the COM port is not recognized at all. When I check in Device Manager, instead of showing as COMx, it appears under libusb-win32 devices → USB JTAG/Serial debug unit (Interface 0).

Has anyone faced a similar issue with the ESP32-S3-DEVKITM-1U specifically on ESP-IDF v5.5.1? I’d appreciate any suggestions on what might be causing the board not to respond or if there’s any known workaround for this version.

Thanks in advance!

In cases where I hold BOOT while pressing RESET, or disconnect the ESP board and reconnect it while holding BOOT, the COM port is not recognized at all. When I check in Device Manager, instead of showing as COMx, it appears under libusb-win32 devices → USB JTAG/Serial debug unit (Interface 0).

Potentially a driver issue; did you mess with Zadig in the past possibly? Generally, the USB-jtag-serial device is what you want to see, but it should also show up as a serial port you can use to flash the device.

@Sprite
Thanks for the response!
Yeah, I think I did use Zadig a while back for something else, but I honestly don’t remember what exactly I did with it. That might have messed up the driver for the ESP32-S3. Could you please guide me on how to fix or reinstall the correct driver so that it shows up properly as a COM port again?

Thanks in advance!

Sorry, I'm not a Windows user so I have no idea.

@Sprite
Thank you for pointing out Zadig!!! That was exactly the issue! I found out the problem, fixed it, and everything’s working perfectly now. Really appreciate your help!

Glad you managed to make it work!