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I’m trying to upload code to my ESP32 board using the Arduino IDE, but I’m consistently getting the following error:

A fatal error occurred: Failed to connect to ESP32: No serial data received.
For troubleshooting steps visit: https://docs.espressif.com/projects/esptool/en/latest/troubleshooting.html

Context:

  • The board was working fine before, and I was able to upload code successfully.
  • I have not changed the USB cable, port, or my development environment.
  • I’m using macOS and the latest ESP32 Arduino core.
  • The correct board is selected (ESP32 Dev Module).

Troubleshooting I’ve Tried:

  1. Checked the USB cable and port – The board is detected under /dev/cu.usbserial-0001.
  2. Manually entered boot mode – Holding the BOOT button while uploading.
  3. Lowered upload speed – Changed to 115200 baud rate in the Arduino IDE.
  4. Reinstalled USB drivers – Tried both CH340 and CP210x drivers.
  5. Tried erasing flash memory using esptool.py.

Question:

What else can I try to fix this error? Could there be a hardware-related issue even though the board was working fine before?

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    "Holding the BOOT button while uploading", Did you hold the BOOT button and press RESET to put the board in upload mode? Commented Mar 22 at 12:22
  • Yes i did press the reset Commented Mar 22 at 13:14
  • did MacOS have an update? Commented Mar 22 at 16:28
  • I didn’t update my MacOS but i even accidentally tested the microcontroller on another windows PC i still got same error. Isn’t this an hardware issue? Commented Mar 23 at 7:36
  • Perhaps there is a hardware bug on the ESP32 or more likely you destroyed the bootloader. If the Bootloader had been overwritten, the Mac had tried to connect, but the ESP did not respond. Search for a howto reinstall the bootloader on a esp32 and reinstall it, to check it. I have no Mac so I can not give you a tip but Expressif provides tools for that like: idf.py and esptool.py. Perhaps you find something like that. Other ideas: Do you have a second working esp32 to check if the MAC, Drivers and Cable work? Did you use Thonny IDE to write a python script on the esp (BL overwritten)? Commented Mar 23 at 16:45

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