NUCLEO-H755ZI-Q: "No STM32 target found" error via ST-LINK/V3 (STM32CubeProgrammer)

[Dharshik]

Hey everyone,

I'm having a rough time getting my NUCLEO-H755ZI-Q board to talk to my PC. Whenever I try to connect using STM32CubeProgrammer or debug from STM32CubeIDE, I keep hitting the same error: Error: No STM32 target found!

I'm using the onboard ST-LINK/V3 plugged in via the USB ST-LINK port. The board lights up fine, and the OS detects the ST-LINK interface without issues, but the moment I try to probe or connect to the target MCU, it fails.

Here is what I've tried so far to troubleshoot:

• Switched between Normal, Hardware Reset, and Software Reset modes in CubeProgrammer.

• Lowered the SWD frequency down to 480 kHz.

• Updated the ST-LINK/V3 firmware to the latest version.

• Double-checked physical jumpers and power source configuration.

  Has anyone run into this specific issue on the H755 before, or know a reliable way to force it into bootloader mode to erase the flash?

  Thanks in advance for any advice!

[jiangfan]

Known good recovery checklist

Try this exact sequence:

1. Remove all external connections from the board
2. Set CubeProgrammer to:
   • Port = SWD
   • Mode = Under Reset / Hardware reset
   • Frequency = 100 to 400 kHz
3. Press and hold NRST
4. Click Connect
5. Release NRST when CubeProgrammer starts attempting connection
6. If connected, perform Full chip erase

NOTE: reviewed answer with help of AI

[jiangfan]

About bootloader mode

If your goal is to recover the part by booting into the ROM bootloader, note:

• the STM32H755 system boot mode depends on the BOOT pins / option bytes
• on a Nucleo board, this may be controlled by flywire, jumpers or solder bridges depending on the board revision

If you can force the device into system memory boot mode, you may be able to connect via UART/USB bootloader instead of SWD, but for most recovery cases the faster path is still:

• connect under reset
• mass erase

NOTE: reviewed answer with help of AI