Issue

• In RHEL6 and older, contents of initramfs image could be extracted using cpio as shown below:

# ls
initramfs-2.6.32-431.el6.x86_64.img

# zcat initramfs-2.6.32-431.el6.x86_64.img | cpio -id
96748 blocks

# ls
bin      dracut-004-335.el6  init                initqueue-settled                    lib    pre-pivot    proc  sysroot  var
cmdline  emergency           initqueue           initqueue-timeout                    lib64  pre-trigger  sbin  tmp
dev      etc                 initqueue-finished  initramfs-2.6.32-431.el6.x86_64.img  mount  pre-udev     sys   usr

• However it does not work when I try to extract the contents of initramfs image on RHEL7 as shown below:

# zcat initramfs-3.10.0-229.4.2.el7.x86_64.img | cpio -id

gzip: initramfs-3.10.0-229.4.2.el7.x86_64.img: not in gzip format
cpio: premature end of archive

# file  initramfs-3.10.0-229.4.2.el7.x86_64.img 
initramfs-3.10.0-229.4.2.el7.x86_64.img: ASCII cpio archive (SVR4 with no CRC)

• How to extract the contents of initramfs image on RHEL7?