Unable to upgrade onboard ST-LINK V3 Firmware

[UFo]

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.

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

Kind regards
T3-Uwe

[Pavel A. · Accepted solution]

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

[UFo]

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