fai 5.3 + debian stretch NFS issues

[Mark Devaney]

I've searched all the relevant postings and cannot find an answer that 
works for our installation.

Is anyone else having issues with debian stretch?

Our previous jessie configuration works fine, but after updating the 
nfsroot to wheezy we either get "mount.nfs: Protocol not supported" in 
dracut (with NFS 4)  or overlay FS issues if we use NFS 3.

FAI configs are default values other than file locations.

I can mount using NFS V4 from the dracut shell but not using NFS V3 - 
our server supports both and I can mount either version from other 
machines so it's not the server side.

FAI_VERSION="5.3.6~bpo8+1"

FAI_DEBOOTSTRAP="stretch http://httpredir.debian.org/debian" (also set 
in apt/sources.list)

dracut NFS protocol error

exports:

/srv/nfs4  *(fsid=0,async,ro,no_subtree_check)
/srv/fai *(async,ro,no_subtree_check)

pxelinux.cfg:

append initrd=initrd.img-4.9.0-3-amd64 ip=dhcp 
root=/srv/fai/nfsroot,nfsvers=3 rootovl 
FAI_FLAGS=verbose,sshd,createvt,reboot 
FAI_CONFIG_SRC=nfs://srv/fai/config,nfsvers=3 FAI_ACTION=install

overlay issues

exports:

/srv  *(fsid=0,async,ro,no_subtree_check)

pxelinux.cfg:

append initrd=initrd.img-4.9.0-3-amd64 ip=dhcp 
root=/fai/nfsroot,nfsvers=4 rootovl 
FAI_FLAGS=verbose,sshd,createvt,reboot 
FAI_CONFIG_SRC=nfs://fai/config,nfsvers=4 FAI_ACTION=install


errors :

touch: cannot touch '/var/log/dmesg.new' : Operation not supported

etc.

ends with FAI: installation aborted

Thank you.