Right sequense for flashing and burning e-fuses
Posted: Thu Mar 12, 2026 9:43 am
Hi.
What is the right sequence and approach to flash an esp32-s3 device and then burn e-fuses as part of a continuous manufacturing flow, with as high automation as possible?
The hard reset via RTS seems to be critical after the flashing to get the device into boot mode. Otherwise I can't start the device after flashing, even if I pull EN low and try different combinations with IO0 (Boot). I also managed to get a device bricked after burning the efuses when the device was still in bootloader mode.
These are the eFuses I'm burning:
DIS_PAD_JTAG
DIS_USB_JTAG
DIS_DOWNLOAD_MODE
Can you please clarify a bit more about the "hard reset" sequence including RTS that esptool is doing?
How do I best sequence this and which mode should the device be in when burning the efuses, so it will boot safely afterwards?
Best,
Daniel
What is the right sequence and approach to flash an esp32-s3 device and then burn e-fuses as part of a continuous manufacturing flow, with as high automation as possible?
The hard reset via RTS seems to be critical after the flashing to get the device into boot mode. Otherwise I can't start the device after flashing, even if I pull EN low and try different combinations with IO0 (Boot). I also managed to get a device bricked after burning the efuses when the device was still in bootloader mode.
These are the eFuses I'm burning:
DIS_PAD_JTAG
DIS_USB_JTAG
DIS_DOWNLOAD_MODE
Can you please clarify a bit more about the "hard reset" sequence including RTS that esptool is doing?
How do I best sequence this and which mode should the device be in when burning the efuses, so it will boot safely afterwards?
Best,
Daniel