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ESP32-S3: Permanently disabling UART ROM download mode

Posted: Wed Jun 15, 2022 2:01 am
by skiddd
Greetings esteemed colleagues,

I am trying to configure Secure Boot V2 via the Project Configuration Menu. I want to set UART ROM download mode to “Permanently disabled”. My first question is, will this also prevent firmware flashing via the USB Serial/JTAG connection?

I understand that in order to make the attack surface smaller, I should permanently disable JTAG and UART ROM download mode. However my concern is how can I legitimately reprogram the device in case an OTA update might semi-brick the device in the future?

Is entering DFU via GPIO0 still an option for the built-in USB Serial/JTAG even after all the suggested EFUSES are burned following the Secure Boot V2 documentation?

Best Regards

Re: ESP32-S3: Permanently disabling UART ROM download mode

Posted: Wed Jun 15, 2022 4:13 am
by ESP_Sprite
Yes, it will disable that. The way to get out of a bad OTA would be to either use rollback or a physical button that boots into a factory partition so the OTA can be retried.

Re: ESP32-S3: Permanently disabling UART ROM download mode

Posted: Wed Jun 15, 2022 3:51 pm
by skiddd
Thank you for the clarifications on this matter.