Hello Andreas!


[ext4 partition overwritten with garbage at the beginning]

quoted

 * photorec from the testdisk package recoveres, luckily!, about 500GB of
   data. Though the content seems to be pretty reasonable, no filenames
   are recovered, since photorec operates without using filesystem 
  knowledge.

 Do you see any chances (besides consulting professional recovery companies)
 getting the filenames back?

There was an ext3grep tool that some people had success with, but when I
looked at it, it was still fairly complex to use.

Thanks for the hint, but the problem with ext3grep is that it seems to
rely on an intact filesystem structure. It even has no option to set
another superblock besides the default one and fails with all commands
I tried ( see https://pzt.me/8q6k ).

Bye, Rudolf.