Dear Team
I hope this message finds you well.
I am currently working with a Nucleo-H755ZI development board (dual-core STM32H755) and encountering a persistent issue when attempting to program or debug the device using STM32CubeIDE and STM32CubeProgrammer.
The following error message appears:
Error: ST-LINK error (DEV_CONNECT_ERR)
Despite multiple attempts and following several troubleshooting steps—including verifying the BOOT0 configuration, updating the ST-LINK firmware, trying "Connect Under Reset", and attempting a full chip erase via STM32CubeProgrammer—the error persists, and I am unable to establish a connection with the device.
Here is a summary of what I have tried:
Verified all physical connections and USB cables.
Updated ST-LINK firmware.
Attempted connection using “Connect Under Reset” while holding down the Reset button.
Ensured I'm targeting the Cortex-M7 core, not the M4.
Attempted a mass erase in STM32CubeProgrammer.
Verified that no low-power or SWD-disabling firmware is loaded.
I would appreciate any guidance or recommendations you can provide to help resolve this issue. If further information or logs are needed, I would be happy to provide them.
Thank you for your support.
Best regards,
