ESP32 DevKit v1 upload failed: “Invalid head of packet” error after trying all troubleshooting steps

[arizalseptino]

Hi everyone,
I’m having trouble uploading code to my ESP32 DevKit v1 using Arduino IDE. Every time I try to upload, I get this error message:

A fatal error occurred: Failed to connect to ESP32: Invalid head of packet (0xC1): Possible serial noise or corruption.
Failed uploading: uploading error: exit status 2

But sometimes change into:

When connected via USB, the board powers on and the port is recognized normally.
However, whenever I try to upload even a simple sketch (like Blink), I always get the same error.

Things I’ve already tried:

1. Holding the BOOT button during upload → still fails.

2. Disconnecting all sensors, relays, or peripherals → still fails.

3. Changing the USB cable and laptop port → still fails.

4. Lowering baud rate to 9600 → still fails.

5. Trying both Arduino IDE and esptool.py manually → same result.

6. The issue started after connecting the ESP32 to an expansion board (power via 12V adapter).

Additional notes:

When powered only via USB, it sometimes uploads fine.

But after connecting it to the expansion board (with 12V adapter), it stopped responding and now always fails to sync.

Question:
What could cause the “Invalid head of packet” error in this situation?
Is it possible the ESP32 DevKit v1 was damaged by the expansion board or power supply?
Any suggestions for testing or fixing it would be greatly appreciated.

[me-no-dev]

how are you connecting that 12V adapter to the dev kit? 5V or 3.3V? What happens if you open the serial monitor while the board is connected to the computer? Do you see anything there?

[arizalseptino]

It was working normally before.
I used the same setup (ESP32 DevKit V1 + expansion board + 12V 1A adapter) and it could read sensors and send data to a web server just fine.

The issue started when I tried to upload a new code.
I’m connecting the 12V adapter (model YL-1210) to the barrel jack on the expansion board labeled “DC 6.5–16V”.