How to fix NFS mount on RPI4b with Ubuntu Server 20.04 arm on boot

So, weird stuff. I have an RPI2b installed 20.04-32 early May, NFS mount works flawlessly on boot.Now I got an RPI4b and tried 20.04-64/32 and the same NFS mount gloriously fails on boot.

I've got a Synology NAS and can mount the share just fine after boot with sudo mount -aI got my entry in fstab and it fails. It seems the network is not available when systemd tries to mount on boot.I tried it with _netdevs, x-systemd.after=network-online.target to no avail.The fstab entry is directly to the local IP address, so no resolving and no external network involved.

So I went to just Pi-Image a clean 20.04-32 and started from the top.Updated apt, upgraded, installed nfs-common, tried to manually mount and it worked. Added the same entry to fstab as on the RPI2b, automount from the shell worked, rebooted and it fails again.

So I dug into the syslog and systemctl.

cat /var/log/syslog | grep -C 5 "remote-fs.target"May 30 20:34:55 ubuntu mount[1222]: mount.nfs: Network is unreachableMay 30 20:34:55 ubuntu systemd[1]: media-nas-emulation.mount: Mount process exited, code=exited, status=32/n/aMay 30 20:34:55 ubuntu systemd[1]: media-nas-emulation.mount: Failed with result 'exit-code'.May 30 20:34:55 ubuntu systemd[1]: Failed to mount /media/nas/emulation.May 30 20:34:55 ubuntu systemd[1]: Dependency failed for Remote File Systems.May 30 20:34:55 ubuntu systemd[1]: remote-fs.target: Job remote-fs.target/start failed with result 'dependency'....

So by the looks of it, remote-fs.target failed. It should be called at some point during boot but isn't.Right after boot:

ubuntu@ubuntu:~$ sudo systemctl | grep remote-fsremote-fs-pre.target        loaded active     active          Remote File Systems (Pre) 

So I do a manual start and check again

ubuntu@ubuntu:~$ sudo systemctl start remote-fs.targetubuntu@ubuntu:~$ sudo systemctl | grep remote-fsremote-fs-pre.target        loaded active active    Remote File Systems (Pre)remote-fs.target        loaded active active    Remote File Systems

So manually starting the target works, and the NFS mount is available automatically right afterwards.

So it seems something's really wrong and remote-fs.target never is called, even after the network is up.On the RPi2b with 20.04 32b the NFS just mounts during boot with systemd reporting success.

Does anyone have any idea what's wrong and/or how to fix it?