Unable to unpack initrd.img-4.4.0-36-generic

[vvhk]

I'm filing a bug report against initramfs-tools because I don't know which package is better. The initrd file produced by "update-initramfs" cannot be unpacked with cpio:

$ file /boot/initrd.img-4.4.0-36-generic
/boot/initrd.img-4.4.0-36-generic: ASCII cpio archive (SVR4 with no CRC)

$ stat /boot/initrd.img-4.4.0-36-generic | grep Size
  Size: 45048327 Blocks: 87988 IO Block: 1024 regular file

$ cpio -id < /boot/initrd.img-4.4.0-36-generic
44 blocks

$ tree ./
./
└── kernel
    └── x86
        └── microcode
            └── GenuineIntel.bin

$ du -sh kernel/
36K kernel/

On another machine, the initrd (same version) is a gzip'ed archive (this one isn't) and unpacks just fine. On this machine, with this initrd, I also have a problem as explained in bug 1638983, so it could be related. Decided to file another bug for initrd.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: initramfs-tools 0.122ubuntu8.5
ProcVersionSignature: Ubuntu 4.4.0-36.55-generic 4.4.16
Uname: Linux 4.4.0-36-generic x86_64
NonfreeKernelModules: zfs zunicode zcommon znvpair zavl nvidia_uvm nvidia_drm nvidia_modeset nvidia
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
CurrentDesktop: Unity
Date: Tue Nov 8 13:13:15 2016
InstallationDate: Installed on 2016-07-23 (108 days ago)
InstallationMedia: Ubuntu 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719)
PackageArchitecture: all
SourcePackage: initramfs-tools
UpgradeStatus: No upgrade log present (probably fresh install)

[Ike Panhc (ikepanhc)]

https://ikepanhc.wordpress.com/2019/09/26/unpack-initrd-on-x86-platform/

Perhaps this can help you.