package amd64-microcode 3.20180524.1~ubuntu0.16.04.2 failed to install/upgrade: subprocess installed post-removal script returned error exit status 1

[fran]

trying to install amd64-microcode updates fail

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: amd64-microcode 3.20180524.1~ubuntu0.16.04.2
ProcVersionSignature: Ubuntu 4.10.0-28.32~16.04.2-generic 4.10.17
Uname: Linux 4.10.0-28-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.10
AptOrdering:
 amd64-microcode: Remove
 initramfs-tools: Configure
 NULL: ConfigurePending
Architecture: amd64
Date: Tue Jul 2 14:12:12 2019
DpkgTerminalLog:
 Removing amd64-microcode (3.20180524.1~ubuntu0.16.04.2) ...
 update-initramfs: deferring update (trigger activated)
 cp: cannot create regular file '/cdrom/casper/initrd.gz.new': No such file or directory
 dpkg: error processing package amd64-microcode (--remove):
  subprocess installed post-removal script returned error exit status 1
ErrorMessage: subprocess installed post-removal script returned error exit status 1
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.2
 apt 1.2.24
SourcePackage: amd64-microcode
Title: package amd64-microcode 3.20180524.1~ubuntu0.16.04.2 failed to install/upgrade: subprocess installed post-removal script returned error exit status 1
UpgradeStatus: No upgrade log present (probably fresh install)