Esp32S3 : Problem during the flash of a proprietary board using an Esp32S3

[ThomasESP32]

Good morning,


I am working as a firmware engineer for a company.

An electronic board using an Esp32S3 has been designed and needs to be flashed in production (With Esptool).

The problem is the following : When an USB-C cable is connected between the board and the computer (Before the flash of

the component), windows is playing a connected sound, then a disconnected sound, then a connected sound and so on ...

It seems that the board is "seen" by windows then not and so on ...


Unfortunately, if I run the esptool in order to flash the board when it is not seen by windows, esptool tells me

that the esp32s3 device is not present on the COMX port. So this is a problem in production. We have to restart the flash

process many times on many boards and we are "loosing time".

Is there a way to solve this problem please ?


Best regards,

[krzychb]

Hi ThomasESP32,

When the ESP32-S3 cannot boot normally (empty flash, invalid firmware, flash power-up issues, etc.), an internal timer keeps resetting the chip every few seconds. Each reset re‑initializes the USB-Serial-JTAG peripheral, so Windows repeatedly sees the USB device connect and disconnect. The USB COM port is only stable once the chip either:

- Enters download (bootloader) mode, or
- Boots a valid, stable firmware from flash.

For some option how to resolve this issue, please check the following FAQ https://docs.espressif.com/projects/esp ... the-reason