Thx for the quick response.
First try was on Thinkpad T440.
But i can tell you now ... i created an false alarm ;-)
A few minutes ago i tried some other .img to usb tools for windows.
I wrote the .img to USB stick with balenaEtcher.
Now booting on my old Thinkpad T440 worked without problems!
.vbs, rufus and ventoy was not successful for creating.
Thanks for this project. I will create some quick and dirty storage nodes with qlogic FC HBAs and LSI RAID-Controllers to temporary extend backup capacity at work.
Case closed ;-)