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Duc
Explorer II
October 18, 2025
Solved

Unable to connect to STM32MP257F-DK board via ST-LINK – Debug Authentication issue?

  • October 18, 2025
  • 2 replies
  • 324 views

Hi ST Community,

I’m using the STM32MP257F-DK board and successfully followed this guide: 

Modify, rebuild and reload the firmware 

Everything worked fine during the initial setup and firmware modification. Now I’m trying to flash a new image to the SD card and connect to the board again, but I’m unable to establish a connection via ST-LINK. Here’s the error I get:

ST-LINK SN : 003E004A3234510636303532 
ST-LINK FW : V3J16M8B5S1 
Board : STM32MP257F-DK 
Voltage : 3.29V 
Error: Unable to get core ID 
Error: No STM32 target found! If your product embeds Debug Authentication, please perform a discovery using Debug Authentication

I’ve set the boot switches to the OFF position (boot from UART/USB), and I suspect that during the previous steps, Secure Boot may have been enabled or modified without me realizing it. Could this be preventing me from accessing the board now?

I’ve already tried:

  • Updating ST-LINK firmware

  • “Connect under reset” mode

  • Checking physical connections and voltage

Is there a way to verify or reset the Secure Boot configuration? Or to recover access to the board if Debug Authentication is now required?

Any help or guidance would be greatly appreciated!

Thanks,

Duc Le

 

    This topic has been closed for replies.
    Best answer by Duc

    I fixed it! The issue was with my cable, so I replaced it with a new one and the problem is resolved.

    2 replies

    D
    DucAuthorAnswer
    Explorer II
    October 18, 2025

    I fixed it! The issue was with my cable, so I replaced it with a new one and the problem is resolved.

    L
    Lmantou
    Visitor II
    October 29, 2025

    Hello Duc,

    I have the same problem, i tried to connect the board with stm32cubeprogrammer and I got the same issue, even if the cable is good, i’m using windows 11, this is the first time I plugged the board with my pc, the board is fresh, is there any steps to do before connecting to stlink v3 programme ?

    NB: all switches for boot are 0

    best regards

    Lmantou

    D
    DucAuthor
    Explorer II
    October 30, 2025

    Hi @Lmantou,

    On the STM3257F-DK, there are two Type-C ports, right? One for power and UART, and the other for connecting to the STLink. Since you mentioned you're experiencing the same issue as I am, I’m guessing you’ve got the cable for power and UART working fine, as you’re able to get the UART log. The issue seems to be with the other port, the one connected to the STLink. Have you double-checked that this connection is secure and working properly?

     

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