Hm, sorry for posting in wrong forum.
Ok, good idea with initrd. But now i realise that something is wrong, because 4.2.1 makes the same error!

Tested 4.2.2, 4.2.1 and 4.2.0 always the same problem (with kernel and initrd).
But maybe i mean 4.1.2 and not 4.2.1. But can not find 4.1.2 on the plop server. Where can i download it? I like to test if it works with 4.1.2.
On the server side i see this message:
mountd[1813]: authenticated mount request from 10.0.0.100:897 for /srv/tftp/ploplinux (/srv/tftp/ploplinux)
Edit:
Ok, found 4.1.2 and tested:
Kernel and initrd from 4.1.2 -> mount ok but plop not found (think this is ok, because data is from 4.2.2)
Testet with 4.2.2 kernel and initrd 4.1.2 -> mount ok but plop not found (think this is ok, because data is from 4.2.2)
Kernel 4.1.2 and initrd 4.2.2 -> system hangs before nfs share is mounted. (kernel panic, FATAL: Kernel to old)
So it works on 4.1.2 but not in 4.2.0/1/2. It looks like the failure is in initrd. But strange is that no one else has this problem.
