ubuntu 20.04 ipxe boot fails

[Aaron B]

The problem:
The following iPXE cmdline fails to boot the 20.04 Desktop iso served via NFS but works flawlessly for 18.04 and earlier:
"kernel images/ubuntu_desktop_20/casper/vmlinuz
initrd images/ubuntu_desktop_20/casper/initrd
imgargs vmlinuz initrd=initrd root=/dev/nfs boot=casper netboot=nfs nfsroot=192.168.5.1:/var/www/images/ubuntu_desktop_20/ ip=dhcp --
boot"

During early boot, the only error message printed is:
"Unable to find a live file system on the network" with no further help on why the failure occoured or how to resolve it.

How to reproduce:
1. Download the official ubuntu desktop iso
2. Copy casper directory to nfsroot location
5. Boot client PC
6. Watch boot fail

I am not sure why it's failing.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[papamoose (papam0ose)]

This comment only serves to help OP an not debug the reason NFS boot doesn't work.

I was able to boot the iso using http only:

kernel ${boot-url}nfs/focal/casper/vmlinuz
initrd ${boot-url}nfs/focal/casper/initrd
imgargs vmlinuz initrd=initrd boot=casper ip=dhcp url=${boot-url}ubuntu/focal/ubuntu-20.04.1-desktop-amd64.iso maybe-ubiquity
boot

If you find out how to boot via NFS I'd like to know how. :)