I was having the same issue "NFS over TCP not available...". I found I was missing ".disk" from the Ubuntu 20.04 ISO. I copied it to my nfs share and I'm now able to boot all the way with out issue.
I was having the same issue "NFS over TCP not available...". I found I was missing ".disk" from the Ubuntu 20.04 ISO. I copied it to my nfs share and I'm now able to boot all the way with out issue.