I have again a strange problem with booting pxe and mounting NFS share.
Tried with plop 19.4 and 20.1.
It has begun with an error "shared library libnsl.so.2 not found".
So ok, i made a symlink in the initrd:
ln -s libnsl-2.30.so libnsl.so.2
Now this error is gone, but i get error "nolock" is needed.
So i added the option "nolock".
Then i get "mount.nfs: Protocol is not supported".

So i tried mounting with "nfsver=3", "vers=3" and always get "mount.nfs: Protocol is not supported".
If i try with "vers=4" then i get "mounting failed, reason given by server: No such file or directory" what is correct because it is a NFS3 share.
When mountin it directly on the debian server all is ok, when mounting on LinuxMint all is ok...
What is wrong here? I am running out of ideas...

Edit: Ok, switching to NFSv4 seemse to solve the problem. But it looks like plop can not mount NFSv3.