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Esp32S3 : Problem during Esp32S3 Flash using ESPTool
Posted: Wed Dec 31, 2025 12:14 pm
by ThomasESP32
Good afternoon,
when flashing cards containing an Esp32S3 using ESPTool, I sometimes get an error.
Please see the picture in attachment.
Could you please tell me what can I do ?
Does it mean that the device has not been found on the COM Port ?
Best regards,
Thomas TRUILHE
Re: Esp32S3 : Problem during Esp32S3 Flash using ESPTool
Posted: Wed Dec 31, 2025 5:37 pm
by ujurmsde
Is your device in boot mode? Have you pressed boot button when powering on the device?
Re: Esp32S3 : Problem during Esp32S3 Flash using ESPTool
Posted: Wed Dec 31, 2025 6:46 pm
by lbernstone
The most likely cause of this issue is a bad cable. Make sure your cable is not folded or coiled. Lower the upload speed if you consistently have issues.
Esptool (and the flash tool you pictured) send a signal to attempt to set the device into download mode. If the device is stuck in a tight boot loop, it has no time available to process that signal (especially if using usb-cdc). You can hold the boot button (gpio0) low while plugging the device into USB to manually start download mode, then upload normally.
Re: Esp32S3 : Problem during Esp32S3 Flash using ESPTool
Posted: Tue Jan 06, 2026 8:13 am
by ThomasESP32
Because we are trying to flash a proprietary bord, there is no pusbutton in order to
set GPIO0 to ground.
The cable used is a "standard" smartphone USB-C cable.
Do you think it is a good idea if we try to flash the card with a shielded cable ??
Thank you for your help