Installer hangs when PXE booted

[Matt Corddry]

I was running the 20.04.1 installer from a LiveCD, which I had booted via PXE with the ISO on a read-only NFS share. It had a log message about waiting for the CD in the drive, which I wasn't able to bypass.

The installer hung. I ended up killing an installer subprocess, which kicked me into the bug report workflow.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: ubiquity 20.04.15.2
ProcVersionSignature: Ubuntu 5.4.0-42.46-generic 5.4.44
Uname: Linux 5.4.0-42-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu27.4
Architecture: amd64
CasperMD5CheckResult: pass
CasperVersion: 1.445.1
Date: Sun Dec 13 09:53:24 2020
InstallCmdLine: BOOT_IMAGE=ubuntu/20.04.1-desktop-amd64/vmlinuz initrd=ubuntu/20.04.1-desktop-amd64/initrd root=/dev/nfs boot=casper netboot=nfs nfsroot=192.168.0.3:/volume1/Software/ubuntu/20.04.1-desktop-amd64 file=/cdrom/preseed/ubuntu.seed ip=dhcp rw verbose
LiveMediaBuild: Ubuntu 20.04.1 LTS "Focal Fossa" - Release amd64 (20200731)
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)