[SOLVED] Failed to connect to ESP32: Timed out waiting for packet header


Have you ever had difficulties while uploading code to an ESP32 board? This article deals with one of the most common errors that occurs during code uploading: “Failed to connect to ESP32: Timed out waiting for packet header.”
To tackle this problem, we will introduce two methods.

Steps to Troubleshooting “Failed to connect to ESP32” Error

First of all, disconnect all wires connected to the ESP32 board. This simple thing might solve the issue! (Because the serial or USB pins could be incorrectly connected, preventing the programming process.)
But sometimes, we have this issue because the “flashing/uploading” modes are not switched automatically. Therefore, when programming the ESP32 board in Arduino IDE Software, the ESP32 and the software fail to make a connection, resulting in the following error.

esp32 error: failed to connect to esp32

A Temporary Solution

The first solution: press and hold the “BOOT/FLASH” button while programming the ESP32 board. But this can be annoying when programming ESP32 repeatedly (especially when you want to debug and test the code on the board).

A Permanent Solution

Put a 10µF capacitor between the “EN” and “GND” pins so that ESP32 can automatically switch between the “flashing/uploading” modes. To test this, it’s recommended to try it first with a breadboard.

solved failed to connect to esp32 circuit

If you have achieved the desired result, you can now solder the 10µF capacitor on the board.

After soldering the capacitor, make sure to use a multimeter to see if it’s done correctly: set the multimeter to the diode test mode; there should be no connection between the soldered pins and the side ones.
Finally, program the ESP32 board. If the capacitor is correctly soldered: (a) you no longer need to press and hold the “BOOT/FLASH” button, and (b) you won’t see the “Failed to connect to ESP32: Timed out waiting for packet header” error anymore.

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