I was able to work-around the issue and I hope it will help to find a (better) solution. I am not familiar with perl, mdadm and I am not sure if fai has to differ here between software raid and fake-hw-raid - and how. Maybe change the regexp to "md[0-9]{3,3}" because software raid has often less then 3 digits by default.
see attached "nfsroot.patch" Mit freundlichen Grüßen/Best regards Stefan Lauterwasser Software Engineer
nfsroot.patch
Description: nfsroot.patch