[Galaxy Tab S Q&A, Help & Troubleshooting] retiredtab:
Here is the initrd.img inside recovery.img

$ xz -dc < initrd.img | cpio -idmv
acct
bin
bugreports
cache
config
d
data
default.prop
dev
etc
etc/mke2fs.conf
etc/mkshrc
etc/recovery.fstab
fstab.universal5420
init
init.rc
mnt
odm
odm/app
odm/bin
odm/firmware
odm/framework
odm/lib
odm/lib64
odm/overlay
odm/priv-app
oem
plat_file_contexts
plat_hwservice_contexts
plat_property_contexts
plat_seapp_contexts
plat_service_contexts
proc
product
prop.default
res
res/images
res/images/erasing_text.png
res/images/error_text.png
res/images/font.png
res/images/font_menu.png
res/images/ic_back.png
res/images/ic_back_sel.png
res/images/ic_factory_reset.png
res/images/ic_factory_reset_sel.png
res/images/ic_options_advanced.png
res/images/ic_options_advanced_sel.png
res/images/ic_reboot.png
res/images/ic_reboot_sel.png
res/images/ic_system_update.png
res/images/ic_system_update_sel.png
res/images/icon_error.png
res/images/installing_security_text.png
res/images/installing_text.png
res/images/logo_image.png
res/images/loop00000.png
res/images/loop00001.png
res/images/loop00002.png
res/images/loop00003.png
res/images/loop00004.png
res/images/loop00005.png
res/images/loop00006.png
res/images/loop00007.png
res/images/loop00008.png
res/images/loop00009.png
res/images/loop00010.png
res/images/loop00011.png
res/images/loop00012.png
res/images/loop00013.png
res/images/loop00014.png
res/images/loop00015.png
res/images/loop00016.png
res/images/loop00017.png
res/images/loop00018.png
res/images/loop00019.png
res/images/loop00020.png
res/images/loop00021.png
res/images/loop00022.png
res/images/loop00023.png
res/images/loop00024.png
res/images/loop00025.png
res/images/loop00026.png
res/images/loop00027.png
res/images/loop00028.png
res/images/loop00029.png
res/images/no_command_text.png
res/images/progress_empty.png
res/images/progress_fill.png
res/images/stage_empty.png
res/images/stage_fill.png
res/keys
sbin
sbin/acpi
sbin/adbd
sbin/awk
sbin/base64
sbin/basename
sbin/blockdev
sbin/bu
sbin/cal
sbin/cat
sbin/chcon
sbin/chgrp
sbin/chmod
sbin/chown
sbin/chroot
sbin/chrt
sbin/cksum
sbin/clear
sbin/cmp
sbin/comm
sbin/cp
sbin/cpio
sbin/cut
sbin/date
sbin/dd
sbin/df
sbin/diff
sbin/dirname
sbin/dmesg
sbin/dos2unix
sbin/du
sbin/e2fsck
sbin/e2fsdroid
sbin/e2fsdroid_static
sbin/echo
sbin/env
sbin/expand
sbin/expr
sbin/fallocate
sbin/false
sbin/file
sbin/find
sbin/flock
sbin/fmt
sbin/free
sbin/fsck.exfat
sbin/fsck.ext4
sbin/fsck.f2fs
sbin/fsck.ntfs
sbin/fsck_msdos
sbin/getenforce
sbin/getprop
sbin/grep
sbin/groups
sbin/gunzip
sbin/gzip
sbin/head
sbin/hostname
sbin/hwclock
sbin/id
sbin/ifconfig
sbin/inotifyd
sbin/insmod
sbin/install
sbin/ionice
sbin/iorenice
sbin/kill
sbin/killall
sbin/ln
sbin/load_policy
sbin/log
sbin/logname
sbin/losetup
sbin/ls
sbin/lsmod
sbin/lsof
sbin/lspci
sbin/lsusb
sbin/md5sum
sbin/microcom
sbin/mkdir
sbin/mke2fs
sbin/mke2fs_static
sbin/mkfifo
sbin/mkfs.exfat
sbin/mkfs.ext4
sbin/mkfs.f2fs
sbin/mkfs.ntfs
sbin/mknod
sbin/mkswap
sbin/mktemp
sbin/modinfo
sbin/modprobe
sbin/more
sbin/mount
sbin/mount.ntfs
sbin/mountpoint
sbin/mv
sbin/netstat
sbin/nice
sbin/nl
sbin/nohup
sbin/od
sbin/paste
sbin/patch
sbin/pgrep
sbin/pidof
sbin/pkill
sbin/pmap
sbin/printenv
sbin/printf
sbin/ps
sbin/pwd
sbin/readlink
sbin/realpath
sbin/reboot
sbin/recovery
sbin/renice
sbin/resize2fs
sbin/restorecon
sbin/rm
sbin/rmdir
sbin/rmmod
sbin/runcon
sbin/sed
sbin/sendevent
sbin/seq
sbin/setenforce
sbin/setprop
sbin/setsid
sbin/sgdisk
sbin/sh
sbin/sha1sum
sbin/sha224sum
sbin/sha256sum
sbin/sha384sum
sbin/sha512sum
sbin/sleep
sbin/sload.f2fs
sbin/sort
sbin/split
sbin/sswap
sbin/start
sbin/stat
sbin/stop
sbin/strings
sbin/stty
sbin/swapoff
sbin/swapon
sbin/sync
sbin/sysctl
sbin/tac
sbin/tail
sbin/tar
sbin/taskset
sbin/tee
sbin/time
sbin/timeout
sbin/top
sbin/touch
sbin/toybox_static
sbin/tr
sbin/true
sbin/truncate
sbin/tty
sbin/tune2fs
sbin/ueventd
sbin/ulimit
sbin/umount
sbin/uname
sbin/uniq
sbin/unix2dos
sbin/unzip
sbin/uptime
sbin/usleep
sbin/uudecode
sbin/uuencode
sbin/vmstat
sbin/watchdogd
sbin/wc
sbin/which
sbin/whoami
sbin/xargs
sbin/xxd
sbin/yes
sbin/zcat
sbin/zip
sdcard
sepolicy
storage
sys
system
tmp
ueventd.rc
ueventd.universal5420.rc
vendor_file_contexts
vendor_hwservice_contexts
vendor_property_contexts
vendor_seapp_contexts
vendor_service_contexts
vndservice_contexts
18161 blocks