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UFo
Associate
February 15, 2026
Solved

Unable to upgrade onboard ST-LINK V3 Firmware

  • February 15, 2026
  • 2 replies
  • 181 views

Hi all.
I tried to upgrade my onboard ST-Link V3 (STM32U5G9j-DK2).
I use STM32CubeProgrammer for MAC V2.21.
The upgrade process breaks with this message:
"ST-Link device lost when exiting upgrade mode"

In this situation
the COM-LED red is ON,
the COM-LED yellow is BLINKING,
the PWR-LED is OFF.

image.jpeg

How can I reactivate the onboard ST-LINK V3 in this situation?

Kind regards
T3-Uwe

Best answer by Pavel A.

Check the USB cable.

Do the update on a decent Windows PC. If nothing of the ST software is installed on the Windows PC, get the small  standalone updater: https://www.st.com/en/development-tools/stsw-link007.html

PavelA_0-1771208056153.png

 

2 replies

Pavel A.
Pavel A.Best answer
Super User
February 16, 2026

Check the USB cable.

Do the update on a decent Windows PC. If nothing of the ST software is installed on the Windows PC, get the small  standalone updater: https://www.st.com/en/development-tools/stsw-link007.html

PavelA_0-1771208056153.png

 

UFo
UFoAuthor
Associate
February 16, 2026

Surprisingly, the Upgrade worked under Windows. 
Thanks a lot. 
T3-Uwe