ZBT-1 (SkyConnect) stopped working - setup error: serial port is locked by another application (ZHA)

Hi all,
I have 2 ZBT-1 sticks in my system: one for ZHA and the other for Matter. After an update in which I updated several components, ZHA no longer works. The integration reports “Setup error: serial port is locked by another application”. Neither reloading Home Assistant nor restarting the system helped.

Even unplugging and replugging the two ZBT-1 sticks did not change anything.

When I try to reconfigure ZHA, I get the error message: “Connection failed”.

There is also an error message when I try to flash the firmware (7.4.4.1): “The action update/install could not be executed: failed to flash firmware”.

What else can I do to make ZHA work again?

Translated with DeepL.com (free version)

if you configured them with paths like /dev/ttyUSB0 , they probably changed ports.
Try to configure with /dev/path/by-id/…

No, I configured it with by-id.