Thanks @Tech_JA and @nevj for the praise. 
Seems I (hopefully) could resolve her problem…
So what´s left for me to do is taking care of my own grub entries to solve my kernel panic issue I posted here.
Just happened to me again today.
For now I´m trying to add rootdelay=10 manually as a boot option.
Hope it helps. 
Happy Easter to all. 
Many greetings from Rosika. 