diff --git a/README.md b/README.md
index 45d1f28..6c4a924 100644
--- a/README.md
+++ b/README.md
@@ -1,48 +1,183 @@
-# initramfs
-Tiny initramfs for suckless systems
-
 Features
---------
-- POSIX compliance
+========
+
+- No `local`'s, no bashisms, only POSIX shell
 - Easy configuration
 - LUKS
 - LVM
 - mdev, mdevd, eudev
 
 Installation
-------------
-Requirements:
-* busybox
-  - --install [-s] [DIR]
-  - mdev
-  - switch_root
-  - mount
-  - umount
-  - blkid
-* kmod
-* cryptsetup - LUKS
-* lvm2 - LVM
-* util-linux - PARTUUID
+============
+
+Dependencies
+------------
+
+* POSIX shell
+* `toybox` OR `busybox` OR `sbase/ubase` OR `coreutils/util-linux`
+* `mdev` OR `mdevd` OR `eudev`
+* `kmod`
+  - Not required for monolithic kernel (builtin modules)
+* `cryptsetup`
+  - Required for LUKS support
+* `lvm2`
+  - Required for LVM support
+
+Usage
+-----
 
-Download & Setup:
 ```
-git clone https://github.com/illiliti/initramfs
-cd initramfs
+usage: ./tinyramfs [option]
+       -o, --output <file>  set initramfs image name
+       -c, --config <file>  set config file path
+       -m, --moddir <dir>   set modules directory
+       -k, --kernel <ver>   set kernel version
+       -F, --files  <dir>   set files directory
+       -d, --debug          enable debug mode
+       -f, --force          overwrite initramfs image
 ```
-TODO
 
 Configuration
--------------
-TODO
+=============
+
+```sh
+# debug mode
+#
+debug=0
+
+# overwrite initramfs
+#
+force=0
+
+# initramfs name
+#
+# default - /tmp/initramfs-$kernel
+# example - output="/tmp/myinitramfs.img.gz"
+#
+output=""
+
+# monolithic kernel
+#
+monolith=0
+
+# modules directory
+#
+# default - /lib/modules
+# example - moddir="/mnt/root/lib/modules"
+#
+moddir=""
+
+# kernel version
+#
+# default - $(uname -r)
+# example - kernel="5.4.18_1"
+#
+kernel=""
+
+# compression program
+#
+# default - gzip -9
+# example - compress="pigz -9"
+#
+compress=""
+
+# root
+#
+# supported - PARTUUID, DEVICE, LABEL, PARTUUID
+# example -
+#   root="/dev/sda1"
+#   root="PARTUUID=35f923c5-083a-4950-a4da-e611d0778121"
+#
+root=""
+
+# root type
+#
+# default - autodetected
+# example - root_type="btrfs"
+#
+root_type=""
+
+# root options
+# example - see fstab(5)
+#
+root_opts=""
+
+# device manager
+# supported - udev, mdev, mdevd
+#
+devmgr=""
+
+# hostonly mode
+#
+hostonly=0
+
+# additional modules
+# example - modules="fat crc32c_generic"
+#
+modules=""
+
+# exclude modules
+# example - modules_exclude="wmi fuse"
+#
+modules_exclude=""
+
+# additional binaries
+# example - binaries="ls cat /path/to/mycustomprog"
+#
+binaries=""
+
+# LVM support
+#
+lvm=0
+
+# LVM options
+#
+# supported - tag, name, group, config, discard
+# description -
+#   tag - trigger lvm by tag
+#   name - trigger lvm by logical volume name
+#   group - trigger lvm by volume group name
+#   config - embed host lvm config
+#   discard - enable issue_discards
+# example -
+#   lvm_opts="tag=lvm-server"
+#   lvm_opts="name=lv1,group=vg1"
+#   lvm_opts="config=1,discard"
+#   lvm_opts="discard=1"
+#
+lvm_opts=""
+
+# LUKS support
+#
+luks=0
+
+# LUKS encrypted root
+#
+# supported - PARTUUID, DEVICE, LABEL, PARTUUID
+# example -
+#   luks_root="/dev/sda1"
+#   luks_root="PARTUUID=35f923c5-083a-4950-a4da-e611d0778121"
+#
+luks_root=""
+
+# LUKS options
+#
+# supported - key, name, header, discard
+# description -
+#   key - embed key
+#   name - device mapper name
+#   header - embed header
+#   discard - enable allow-discards
+# example -
+#   luks_opts="key=/path/to/keyfile,name=myluksroot,header=/path/to/header,discard"
+#   luks_opts="discard=1"
+#
+luks_opts=""
+```
+
+TODO document kernel command-line parameters
 
 License
--------
+=======
+
 Licensed under GPLv3
-
-Exceptions:
-
-The "mdev.conf" configuration file is modified version from "mdev-like-a-boss" project, Copyright (c) 2012-2020, Piotr Karbowski <piotr.karbowski@gmail.com>.
-Please consult the license notice in the file for terms and conditions.
-
-The "storage-device" script is modified version from "mdev-like-a-boss" project, Copyright (c) 2012-2020, Piotr Karbowski <piotr.karbowski@gmail.com>.
-Please consult the license notice in the file for terms and conditions.
diff --git a/config b/config
index 2b92ecb..094d2f2 100644
--- a/config
+++ b/config
@@ -3,91 +3,134 @@
 #
 
 # debug mode
-#debug=0
+#
+debug=0
 
 # overwrite initramfs
-#force=0
-
-# init
-#init=""
+#
+force=0
 
 # initramfs name
-#initramfs=""
+#
+# default - /tmp/initramfs-$kernel
+# example - output="/tmp/myinitramfs.img.gz"
+#
+output=""
 
 # monolithic kernel
-#monolith=""
+#
+monolith=0
 
-# drivers directory
-#moddir=""
+# modules directory
+#
+# default - /lib/modules
+# example - moddir="/mnt/root/lib/modules"
+#
+moddir=""
 
 # kernel version
-#kernel=""
+#
+# default - $(uname -r)
+# example - kernel="5.4.18_1"
+#
+kernel=""
 
 # compression program
-#compress=""
+#
+# default - gzip -9
+# example - compress="pigz -9"
+#
+compress=""
 
 # root
-#root=""
+#
+# supported - PARTUUID, DEVICE, LABEL, PARTUUID
+# example -
+#   root="/dev/sda1"
+#   root="PARTUUID=35f923c5-083a-4950-a4da-e611d0778121"
+#
+root=""
 
 # root type
-#root_type=""
+#
+# default - autodetected
+# example - root_type="btrfs"
+#
+root_type=""
 
 # root options
-#root_opts=""
-
-# util-linux binaries
-#util_linux=0
+# example - see fstab(5)
+#
+root_opts=""
 
 # device manager
-#devmgr=""
+# supported - udev, mdev, mdevd
+#
+devmgr=""
 
 # hostonly mode
-#hostonly=0
+#
+hostonly=0
 
-# additional drivers
-#drivers=""
+# additional modules
+# example - modules="fat crc32c_generic"
+#
+modules=""
 
-# exclude drivers
-#drivers_exclude=""
+# exclude modules
+# example - modules_exclude="wmi fuse"
+#
+modules_exclude=""
 
 # additional binaries
-#binaries=""
+# example - binaries="ls cat /path/to/mycustomprog"
+#
+binaries=""
 
 # LVM support
-#lvm=0
-
-# LVM logical volume name
-#lvm_name=""
-
-# LVM volume group name
-#lvm_group=""
-
-# LVM config
-#lvm_config=0
-
-# LVM issue_discards
-#lvm_discard=0
+#
+lvm=0
 
 # LVM options
-#lvm_args=""
+#
+# supported - tag, name, group, config, discard
+# description -
+#   tag - trigger lvm by tag
+#   name - trigger lvm by logical volume name
+#   group - trigger lvm by volume group name
+#   config - embed host lvm config
+#   discard - enable issue_discards
+# example -
+#   lvm_opts="tag=lvm-server"
+#   lvm_opts="name=lv1,group=vg1"
+#   lvm_opts="config=1,discard"
+#   lvm_opts="discard=1"
+#
+lvm_opts=""
 
 # LUKS support
-#luks=0
+#
+luks=0
 
 # LUKS encrypted root
-#luks_root=""
-
-# LUKS mapper name
-#luks_name=""
-
-# LUKS detached header
-#luks_header="/path/to/header"
-
-# LUKS keyfile
-#luks_keyfile="/path/to/keyfile"
-
-# LUKS allow_discards
-#luks_discard=0
+#
+# supported - PARTUUID, DEVICE, LABEL, PARTUUID
+# example -
+#   luks_root="/dev/sda1"
+#   luks_root="PARTUUID=35f923c5-083a-4950-a4da-e611d0778121"
+#
+luks_root=""
 
 # LUKS options
-#luks_args=""
+#
+# supported - key, name, header, discard
+# description -
+#   key - embed key
+#   name - device mapper name
+#   header - embed header
+#   discard - enable allow-discards
+# example -
+#   luks_opts="key=/path/to/keyfile,name=myluksroot,header=/path/to/header,discard"
+#   luks_opts="discard=1"
+#
+luks_opts=""
diff --git a/tinyramfs b/tinyramfs
index ba64f6a..bba62cf 100755
--- a/tinyramfs
+++ b/tinyramfs
@@ -1,32 +1,27 @@
-#!/bin/sh
+#!/bin/sh -ef
 #
-# tiny initramfs generation tool
+# tiny initramfs
 
-msg() {
+msg()
+{
     case "$1" in
         info)
-            printf "info >> %s\n" "$2" >&2
-            ;;
-        warn)
-            printf "warning >> %s\n" "$2" \
-                   "are you sure you want to continue?" \
-                   "press enter to continue or ctrl+c to exit" >&2
-
-            read -r _
-            ;;
+            printf "info >> %s\n" "$2"
+        ;;
         panic)
             printf "panic >> %s\n" "$2" >&2
             exit 1
-            ;;
+        ;;
     esac
 }
 
-usage() {
+usage()
+{
     cat << EOF
-usage: $0 [option...]
+usage: $0 [option]
        -o, --output <file>  set initramfs image name
        -c, --config <file>  set config file path
-       -m, --moddir <dir>   set drivers directory
+       -m, --moddir <dir>   set modules directory
        -k, --kernel <ver>   set kernel version
        -F, --files  <dir>   set files directory
        -d, --debug          enable debug mode
@@ -35,181 +30,227 @@ usage: $0 [option...]
 EOF
 }
 
-parse_args() {
+parse_args()
+{
     while [ "$1" ]; do
         case "$1" in
             -o | --output)
-                _initramfs="${2:?}"
+                _output="${2:?}"
                 shift 2
-                ;;
+            ;;
             -c | --config)
                 _config="${2:?}"
                 shift 2
-                ;;
+            ;;
             -m | --moddir)
                 _moddir="${2:?}"
                 shift 2
-                ;;
+            ;;
             -k | --kernel)
                 _kernel="${2:?}"
                 shift 2
-                ;;
+            ;;
             -F | --files)
                 _filesdir="${2:?}"
                 shift 2
-                ;;
+            ;;
             -d | --debug)
                 _debug=1
                 shift 1
-                ;;
+            ;;
             -f | --force)
                 _force=1
                 shift 1
-                ;;
+            ;;
             -h | --help)
                 usage
                 exit 0
-                ;;
+            ;;
             *)
-                printf "%s\n\n" "invalid option: '$1'"
+                printf "invalid option: %s\n\n" "$1"
                 usage
                 exit 1
-                ;;
+            ;;
         esac
     done
 }
 
-prepare_environment() {
+prepare_environment()
+{
+    msg info "preparing environment"
+
     for _file in $_config /etc/tinyramfs/config ./config; do
-        [ -f "$_file" ] && . "$_file" && break
+        [ -f "$_file" ] &&
+        {
+            . "$_file"
+            break
+        }
     done || msg panic "failed to source config"
 
     for _dir in $_filesdir /usr/share/tinyramfs ./usr/share/tinyramfs; do
-        [ -d "$_dir" ] && filesdir="$_dir" && break
+        [ -d "$_dir" ] &&
+        {
+            filesdir="$_dir"
+            break
+        }
     done || msg panic "failed to locate required files"
 
-    kernel="${_kernel:-${kernel:-$(uname -r)}}"
-    moddir="${_moddir:-${moddir:-/lib/modules}}"
     debug="${_debug:-${debug:-0}}"
     force="${_force:-${force:-0}}"
-    initramfs="${_initramfs:-${initramfs:-/tmp/initramfs-${kernel}}}"
-    modker="${moddir}/${kernel}"
-}
+    moddir="${_moddir:-${moddir:-/lib/modules}}"
+    kernel="${_kernel:-${kernel:-$(uname -r)}}"
+    output="${_output:-${output:-/tmp/initramfs-${kernel}}}"
 
-create_workdir() {
-    msg info "creating working directory"
-
-    workdir="${XDG_CACHE_HOME:-${TMPDIR:-/tmp}}/initramfs.$$"
-    mkdir -p "$workdir" ||
+    mkdir -p "${workdir=${XDG_CACHE_HOME:-${TMPDIR:-/tmp}}/initramfs.$$}" ||
         msg panic "failed to create working directory"
+
+    workdirbin="${workdir}/usr/bin/"
+    workdirlib="${workdir}/usr/lib/"
+    modker="${moddir}/${kernel}"
+    OLD_IFS="$IFS"
 }
 
-remove_workdir() {
+remove_workdir()
+{
     msg info "removing working directory"
 
     rm -rf "$workdir"
 }
 
-install_requirements() {
+install_requirements()
+{
     msg info "installing requirements"
 
-    # install user specified binaries
-    [ "$binaries"       ] &&
-        for _binary in $binaries; do
-            install_binary "$_binary"
-        done
-
-    # install util-linux binaries
-    [ "$util_linux" = 1 ] &&
-        for _binary in mount blkid; do
-            install_binary "$_binary"
-        done
-
-    # install required binaries
-    for _binary in busybox modprobe; do
+    # install user specified binaries if any
+    for _binary in $binaries; do
         install_binary "$_binary"
     done
+
+    # install required binaries
+    for _binary in \[ sh sleep mount printf setsid switch_root; do
+        install_binary "$_binary"
+    done
+
+    # copy init
+    install -m755 "${filesdir}/init" "${workdir}/init"
+
+    # copy config
+    printf "%s\n" \
+        monolith="$monolith" \
+        root="$root" \
+        root_type="$root_type" \
+        root_opts="$root_opts" \
+        devmgr="$devmgr" \
+        lvm="$lvm" \
+        lvm_opts="$lvm_opts" \
+        luks="$luks" \
+        luks_root="$luks_root" \
+        luks_opts="$luks_opts" \
+        > "${workdir}/etc/config"
 }
 
-create_structure() {
+create_structure()
+{
     msg info "creating directory structure"
 
-    for _dir in dev tmp var run etc usr/lib usr/bin mnt/root proc root sys; do
+    for _dir in etc tmp dev sys proc root usr/lib usr/bin mnt/root; do
         mkdir -p "${workdir}/${_dir}"
     done
 }
 
-create_symlinks() {
+create_symlinks()
+{
     msg info "creating symlinks"
 
     ln -s usr/lib "${workdir}/lib"
     ln -s usr/lib "${workdir}/lib64"
     ln -s usr/bin "${workdir}/bin"
     ln -s usr/bin "${workdir}/sbin"
-    ln -s ../run  "${workdir}/var/run"
     ln -s bin     "${workdir}/usr/sbin"
     ln -s lib     "${workdir}/usr/lib64"
 }
 
-install_devmgr() {
+install_devmgr()
+{
     msg info "installing device manager"
 
+    # TODO investigate booting without device manager
     case "$devmgr" in
         udev)
-            for _binary in udevd udevadm dmsetup; do
+            for _binary in udevd udevadm; do
                 install_binary "$_binary"
             done
 
-            find /usr/lib/udev \
-                ! -path "*rc_keymaps*" \
-                ! -path "*hwdb.d*" \
-                -type f |
+            # exclusively handle requirement
+            [ "$luks" = 1 ] || [ "$lvm" = 1 ] &&
+                install_binary dmsetup
 
-            cpio -pd "$workdir" > /dev/null 2>&1
-            ;;
-        mdev)
-            install -m644  "${filesdir}/mdev.conf"      "${workdir}/etc/mdev.conf"
-            install -Dm755 "${filesdir}/storage-device" "${workdir}/lib/mdev/storage-device"
-            ;;
-        mdevd)
-            for _binary in mdevd mdevd-coldplug; do
+            for _binary in /usr/lib/udev/ata_id /usr/lib/udev/scsi_id; do
+                install -Dm755 "$_binary" "${workdir}${_binary}"
+            done
+
+            set +f; for _file in /usr/lib/udev/rules.d/*; do
+                install -Dm644 "$_file" "${workdir}${_file}"
+            done; set -f
+        ;;
+        mdev | mdevd)
+            [ "$devmgr" = mdev  ] && install_binary mdev
+            [ "$devmgr" = mdevd ] &&
+                for _binary in mdevd mdevd-coldplug; do
+                    install_binary "$_binary"
+                done
+
+            for _binary in ln kill mkdir blkid "${filesdir}/device-helper"; do
                 install_binary "$_binary"
             done
 
-            install -m644  "${filesdir}/mdev.conf"      "${workdir}/etc/mdev.conf"
-            install -Dm755 "${filesdir}/storage-device" "${workdir}/lib/mdev/storage-device"
-            ;;
+            printf "%s\n" \
+                'SUBSYSTEM=block;.* 0:0 660 @device-helper' \
+                > "${workdir}/etc/mdev.conf"
+
+            [ "$monolith" != 1 ] && printf "%s\n" \
+                '$MODALIAS=.*       0:0 660 @modprobe "$MODALIAS"' \
+                >> "${workdir}/etc/mdev.conf"
+        ;;
     esac
 }
 
-install_lvm() {
+install_lvm()
+{
     msg info "installing LVM"
 
-    install_binary lvm
+    for _binary in lvchange vgchange; do
+        install_binary "$_binary"
+    done
 
-    # install lvm config
-    if [ "$lvm_config" = 1 ]; then
-        mkdir -p "${workdir}/etc/lvm"
+    { IFS=,; set -- $lvm_opts; IFS="$OLD_IFS"; }
 
-        cp /etc/lvm/*.conf "${workdir}/etc/lvm"
-    else
-        mkdir -p "${workdir}/etc/lvm"
+    for opt; do
+        case "$opt" in
+            config | config=1)
+                install -Dm644 /etc/lvm/lvm.conf "${workdir}/etc/lvm/lvm.conf"
+                return
+            ;;
+        esac
+    done
 
-        cat << EOF > "${workdir}/etc/lvm/lvm.conf"
-devices {
-    # block discard support
-    issue_discards = ${lvm_discard:-0}
+    mkdir -p "${workdir}/etc/lvm"
+    printf "%s\n" \
+        'devices {' \
+            'write_cache_state = 0' \
+        '}' \
+        'backup {' \
+            'backup  = 0' \
+            'archive = 0' \
+        '}' \
+        'global {' \
+            'use_lvmetad = 0' \
+        '}' \
+        > "${workdir}/etc/lvm/lvm.conf"
 }
 
-global {
-    # disable lvmetad
-    use_lvmetad = 0
-}
-EOF
-    fi
-}
-
-install_luks() {
+install_luks()
+{
     msg info "installing LUKS"
 
     install_binary cryptsetup
@@ -219,61 +260,91 @@ install_luks() {
     [ -e /usr/lib/libgcc_s.so.1 ] &&
         install_library /usr/lib/libgcc_s.so.1
 
-    # copy luks header
-    [ -f "$luks_header" ] &&
-        install -m400 "$luks_header" "${workdir}/root/luks_header"
+    { IFS=,; set -- $luks_opts; IFS="$OLD_IFS"; }
 
-    # copy luks keyfile
-    [ -f "$luks_keyfile" ] &&
-        install -m400 "$luks_keyfile" "${workdir}/root/luks_keyfile"
+    for opt; do
+        case "${opt%%=*}" in
+            header)
+                install -m400 "${opt##*=}" "${workdir}/root/header"
+                luks_opts=$(printf "%s" "$luks_opts" | sed "s|${opt##*=}|/root/header|")
+            ;;
+            key)
+                install -m400 "${opt##*=}" "${workdir}/root/key"
+                luks_opts=$(printf "%s" "$luks_opts" | sed "s|${opt##*=}|/root/key|")
+            ;;
+        esac
+    done
 }
 
-install_driver() {
-    driver="$1"
+install_module()
+{
+    module="$1"
 
-    modprobe -S "$kernel" -D "$driver" 2> /dev/null |
+    modprobe -S "$kernel" -D "$module" 2> /dev/null |
 
-    while read -r driver; do
+    while read -r module || [ "$module" ]; do
 
         # strip unneeded stuff
-        driver="${driver##*builtin*}"
-        driver="${driver##*net*}"
-        driver="${driver#insmod }"
+        module="${module##*builtin*}"
+        module="${module##*net*}"
+        module="${module#insmod }"
 
-        # exclude user specified drivers
-        [ "$drivers_exclude" ] &&
-            for _exclude_driver in $drivers_exclude; do
-                driver="${driver##*${_exclude_driver}*}"
-            done
+        # exclude user specified modules if any
+        for _exclude_module in $modules_exclude; do
+            module="${module##*${_exclude_module}*}"
+        done
 
-        # check empty
-        [ "$driver" ] || continue
-
-        # check if driver already installed
-        [ -e "${workdir}${driver}" ] ||
-            install -Dm644 "$driver" "${workdir}${driver}"
-    done
+        # check if module already installed
+        [ -e "$module" ] && [ ! -e "${workdir}${module}" ] &&
+            install -Dm644 "$module" "${workdir}${module}"
+    done ||:
 }
 
-install_hostonly_drivers() {
-    msg info "installing hostonly drivers"
+install_hostonly_modules()
+{
+    msg info "installing hostonly modules"
 
-    # perform autodetection of drivers via /sys
+    # perform autodetection of modules via /sys
     find /sys -name modalias -exec sort -u {} + |
 
-    while read -r _driver; do
-        install_driver "$_driver"
-    done
+    while read -r _module || [ "$_module" ]; do
+        install_module "$_module"
+    done ||:
 
-    # install user specified drivers
-    [ "$drivers" ] &&
-        for _driver in $drivers; do
-            install_driver "$_driver"
+    # install LVM modules
+    [ "$lvm" = 1 ] &&
+        for _module in dm-thin-pool dm-multipath dm-snapshot dm-cache dm-log dm-mirror; do
+            install_module "$_module"
         done
+
+    # install LUKS modules
+    [ "$luks" = 1 ] &&
+        for _module in aes dm-crypt sha256 sha512 wp512 ecb lrw xts twofish serpent; do
+            install_module "$_module"
+        done
+
+    # install root partition module
+    if [ "$root_type" ]; then
+        install_module "$root_type"
+    else
+        while read -r _ _dir _type _ _ _; do
+            [ "$_dir" = / ] &&
+            {
+                install_module "$_type"
+                break
+            }
+        done < /proc/mounts
+    fi
+
+    # install user specified modules if any
+    for _module in $modules; do
+        install_module "$_module"
+    done
 }
 
-install_all_drivers() {
-    msg info "installing all drivers"
+install_all_modules()
+{
+    msg info "installing all modules"
 
     find \
         "${modker}/kernel/arch" \
@@ -289,202 +360,153 @@ install_all_drivers() {
         "${modker}/kernel/drivers/virtio" \
         -type f 2> /dev/null |
 
-    while read -r _driver; do
+    while read -r _module || [ "$_module" ]; do
 
         # strip path and extension
-        _driver="${_driver##*/}"
-        _driver="${_driver%%.*}"
+        _module="${_module##*/}"
+        _module="${_module%%.*}"
 
-        install_driver "$_driver"
-    done
+        install_module "$_module"
+    done ||:
 }
 
-generate_depmod() {
-    msg info "generating drivers list"
-
-    cp "${modker}/modules.builtin" \
-       "${modker}/modules.order" \
-       "${workdir}${modker}"
-
-    depmod -b "$workdir" "$kernel"
-}
-
-install_binary() {
+install_binary()
+{
     binary=$(command -v "$1")
-    realbin="$(dirname "$binary")/$(readlink "$binary")"
-    fullbin=$(readlink -f "$binary")
-    workdirbin="${workdir}/usr/bin/"
 
-    # check if binary exists
-    [ "$binary" ] || msg panic "$binary doesn't exists"
+    # check if binary exist and builtin
+    case "$binary" in
+        */*)
+            : no operation
+        ;;
+        "")
+            msg panic "$1 doesn't exist"
+        ;;
+        *)
+            { IFS=:; set -- $PATH; IFS="$OLD_IFS"; }
+
+            for _dir; do
+                [ -x "${_dir}/${binary}" ] &&
+                {
+                    binary="${_dir}/${binary}"
+                    break
+                }
+            done || msg panic "couldn't find external $1 binary"
+        ;;
+    esac
 
     # check if binary already installed
-    [ -e "${workdirbin}${fullbin##*/}" ] &&
-        return
+    [ -e "${workdirbin}${binary##*/}" ] && return
 
-    # install symlinks if any
-    [ -h "$binary" ] && {
+    # iterate throught symlinks and copy them
+    while [ -h "$binary" ]; do
+        cp -P "$binary" "$workdirbin"
+        binary="${binary%/*}/$(readlink "$binary")"
+    done
 
-        # symlink may link to symlink
-        [ -h "$realbin" ] &&
-            cp -a "$realbin" "$workdirbin"
+    install -m755 "$binary" "${workdirbin}${binary##*/}"
+    strip "${workdirbin}${binary##*/}" > /dev/null 2>&1 ||:
 
-        cp -a "$binary" "$workdirbin"
-    }
-
-    # install and strip binary
-    install -s -m755 "$fullbin" "${workdirbin}${fullbin##*/}"
-
-    # check static
-    ldd "$binary" > /dev/null 2>&1 || return
+    # check if binary statically linked
+    ldd "$binary" > /dev/null 2>&1 || return 0
 
     # exract paths to libraries
     ldd "$binary" |
 
-    while read -r _library; do
+    while read -r _library || [ "$_library" ]; do
 
         # strip unneeded stuff
         _library="${_library##*vdso*}"
         _library="${_library#* => }"
         _library="${_library% *}"
 
-        # check empty
-        [ "$_library" ] || continue
-
-        install_library "$_library"
-    done
+        [ -e "$_library" ] && install_library "$_library"
+    done ||:
 }
 
-install_library() {
+install_library()
+{
     library="$1"
-    reallib="$(dirname "$library")/$(readlink "$library")"
-    fulllib=$(readlink -f "$library")
-    workdirlib="${workdir}/usr/lib/"
 
     # check if library already installed
-    [ -e "${workdirlib}${fulllib##*/}" ] &&
-        return
+    [ -e "${workdirlib}${library##*/}" ] && return
 
-    # install symlinks if any
-    [ -h "$library" ] && {
+    # iterate throught symlinks and copy them
+    while [ -h "$library" ]; do
+        cp -P "$library" "$workdirlib"
+        library="${library%/*}/$(readlink "$library")"
+    done
 
-        # symlink may link to symlink
-        [ -h "$reallib" ] &&
-            cp -a "$reallib" "$workdirlib"
-
-        cp -a "$library" "$workdirlib"
-    }
-
-    # install library
-    install -s -m755 "$fulllib" "${workdirlib}${fulllib##*/}"
+    install -m755 "$library" "${workdirlib}${library##*/}"
+    strip "${workdirlib}${library##*/}" > /dev/null 2>&1 ||:
 }
 
-install_files() {
-    msg info "installing files"
-
-    cat > "${workdir}/config" << EOF
-debug="$debug"
-init="$init"
-root="$root"
-root_type="$root_type"
-root_opts="$root_opts"
-devmgr="$devmgr"
-#drivers
-lvm="$lvm"
-lvm_name="$lvm_name"
-lvm_group="$lvm_group"
-#lvm_discard
-lvm_args="$lvm_args"
-luks="$luks"
-luks_root="$luks_root"
-luks_name="$luks_name"
-#luks_header
-#luks_keyfile
-luks_discard="$luks_discard"
-luks_args="$luks_args"
-EOF
-
-    install -m644 "${filesdir}/passwd" "${workdir}/etc/passwd"
-    install -m644 "${filesdir}/group"  "${workdir}/etc/group"
-    install -m755 "${filesdir}/init"   "${workdir}/init"
-}
-
-create_initramfs() {
+create_initramfs()
+{
     msg info "creating initramfs image"
 
     # TODO add uncompressed option
 
     # check if image already exist
-    [ "$force" = 0 ] && [ -e "$initramfs" ] &&
-        msg warn "looks like you already have initramfs image"
+    [ "$force" != 1 ] && [ -e "$output" ] &&
+        msg panic "initramfs image already exist"
 
     (
         cd "$workdir"
         find . | cpio -oH newc | ${compress:-gzip -9}
 
-    ) > "$initramfs" 2> /dev/null ||
+    ) > "$output" 2> /dev/null ||
         msg panic "failed to generate initramfs image"
 }
 
-# check root
-[ "$(id -u)" = 0 ] || msg panic "must be run as root"
+# int main()
+{
+    # check root
+    [ "$(id -u)" = 0 ] || msg panic "must be run as root"
 
-parse_args "$@"
-prepare_environment
+    parse_args "$@"
+    prepare_environment
 
-# remove workdir on signals
-# we are doing unset EXIT signal to avoid endless loop
-# because afterwards we execute exit command.
-# also some shells (dash,mksh,etc) doesn't exit on INT
-# signal. as workaround we manually execute exit command.
-# tested bash,dash,mksh,busybox sh
-# TODO fix zsh, ref https://www.zsh.org/mla/users/2015/msg00436.html
-trap "remove_workdir && trap - EXIT && exit" EXIT INT TERM HUP
+    [ "$debug" = 1 ] && set -x
 
-[ "$debug" = 1 ] && {
+    # hacky, but compatible with all posix shells
+    trap '
+        ret="$?"
+        trap - EXIT INT
+        [ "$debug" = 1 ] || remove_workdir
+        [ "$ret"   = 0 ] || msg panic "something went wrong"
+        ' EXIT INT
 
-    # debug shell commands
-    set -x
+    create_structure
+    create_symlinks
 
-    # don't remove anything
-    trap - EXIT INT TERM HUP
+    [ "$lvm"  = 1 ] && install_lvm
+    [ "$luks" = 1 ] && install_luks
+
+    # check monolithic kernel
+    [ "$monolith" != 1 ] && [ -d "$moddir" ] &&
+    {
+        # check hostonly mode
+        if [ "$hostonly" = 1 ]; then
+            install_hostonly_modules
+        else
+            install_all_modules
+        fi
+
+        for _binary in find sort modprobe; do
+            install_binary "$_binary"
+        done
+
+        cp "${modker}/modules.builtin" \
+           "${modker}/modules.order" \
+           "${workdir}${modker}"
+
+        depmod -b "$workdir" "$kernel"
+    }
+
+    install_devmgr
+    install_requirements
+    create_initramfs
+
+    msg info "done! check out - $output"
 }
-
-create_workdir
-create_structure
-create_symlinks
-
-[ "$lvm"  = 1 ] && install_lvm
-[ "$luks" = 1 ] && install_luks
-
-# check monotihic kernel
-[ "$monolith" != 1 ] && [ -d "$moddir" ] && {
-
-    # check hostonly mode
-    if [ "$hostonly" = 1 ]; then
-        install_hostonly_drivers
-
-        # install lvm drivers
-        [ "$lvm" = 1 ] &&
-            for _driver in dm-thin-pool dm-multipath dm-snapshot dm-cache dm-log dm-mirror; do
-                install_driver "$_driver"
-            done
-
-        # install luks drivers
-        [ "$luks" = 1 ] &&
-            for _driver in aes dm-crypt sha256 sha512 wp512 ecb lrw xts twofish serpent; do
-                install_driver "$_driver"
-            done
-    else
-        install_all_drivers
-    fi
-
-    generate_depmod
-}
-
-install_devmgr
-install_files
-install_requirements
-create_initramfs
-
-msg info "done! check out $initramfs"
diff --git a/usr/share/man/man5/tinyramfs.config.5 b/usr/share/man/man5/tinyramfs.config.5
deleted file mode 100644
index 0487c17..0000000
--- a/usr/share/man/man5/tinyramfs.config.5
+++ /dev/null
@@ -1,179 +0,0 @@
-.TH tinyramfs 5 "March 2020" tinyramfs
-
-.SH NAME
-tinyramfs \- configuration options
-
-.SH GENERAL
-.TP
-.BR \fBdebug=\fR"\&\fI {0|1} \fR\&"
-Enable shell debugging
-
-This option also drop you to shell after root partition being mounted in initramfs
-.TP
-
-.TP
-.BR \fBforce=\fR"\&\fI {0|1} \fR\&"
-Disable warning about exists initramfs image
-.TP
-
-.TP
-.BR \fBinit=\fR"\&\fI /path/to/file \fR\&"
-Specify init program
-.TP
-
-.TP
-.BR \fBinitramfs=\fR"\&\fI /path/to/file \fR\&"
-Specify initramfs output name
-.TP
-
-.TP
-.BR \fBmonolith=\fR"\&\fI {0|1} \fR\&"
-Enable monolithic kernel support
-
-This option required if you using monolithic kernel (builtin drivers)
-.TP
-
-.TP
-.BR \fBmoddir=\fR"\&\fI /path/to/dir \fR\&"
-Specify directory of drivers
-.TP
-
-.TP
-.BR \fBkernel=\fR"\&\fI ... \fR\&"
-Specify kernel version
-.TP
-
-.TP
-.BR \fBcompress=\fR"\&\fI ... \fR\&"
-Specify compression program
-.TP
-
-.TP
-.BR \fBroot=\fR"\&\fI ... \fR\&"
-Specify root partition [PARTUUID, UUID, LABEL, DEVICE]
-
-This option is required
-.TP
-
-.TP
-.BR \fBroot_type=\fR"\&\fI ... \fR\&"
-Specify root partition type
-.TP
-
-.TP
-.BR \fBroot_opts=\fR"\&\fI ... \fR\&"
-Specify root partition mount options (comma separated)
-.TP
-
-.TP
-.BR \fButil_linux=\fR"\&\fI {0|1} \fR\&"
-Include util-linux binaries
-
-This option required if you need PARTUUID support
-.TP
-
-.TP
-.BR \fBdevmgr=\fR"\&\fI ... \fR\&"
-Specify device manager [udev, mdev, mdevd]
-
-This option is required
-.TP
-
-.TP
-.BR \fBhostonly=\fR"\&\fI {0|1} \fR\&"
-Enable hostonly mode
-.TP
-
-.TP
-.BR \fBdrivers=\fR"\&\fI ... \fR\&"
-Include additional drivers (space separated)
-
-If host only mode enabled you need to specify your root partition driver
-.TP
-
-.TP
-.BR \fBdrivers_exclude=\fR"\&\fI ... \fR\&"
-Exclude specified drivers (space separated)
-.TP
-
-.TP
-.BR \fBbinaries=\fR"\&\fI ... \fR\&"
-Include additional binaries (space separated)
-.TP
-
-.SH LVM
-
-.TP
-.BR \fBlvm=\fR"\&\fI {0|1} \fR\&"
-Enable LVM support
-
-This option required if you need LVM support
-.TP
-
-.TP
-.BR \fBlvm_name=\fR"\&\fI ... \fR\&"
-Specify logical volume name
-.TP
-
-.TP
-.BR \fBlvm_group=\fR"\&\fI ... \fR\&"
-Specify volume group name
-.TP
-
-.TP
-.BR \fBlvm_config=\fR"\&\fI {0|1} \fR\&"
-Include config from /etc/lvm
-
-This option overwrite lvm_discard option
-.TP
-
-.TP
-.BR \fBlvm_discard=\fR"\&\fI {0|1} \fR\&"
-Enable TRIM requests
-.TP
-
-.TP
-.BR \fBlvm_args=\fR"\&\fI ... \fR\&"
-Pass additional options to lvm
-.TP
-
-.SH LUKS
-
-.TP
-.BR \fBluks=\fR"\&\fI {0|1} \fR\&"
-Enable LUKS support
-
-This option required if you need LUKS support
-.TP
-
-.TP
-.BR \fBluks_root=\fR"\&\fI ... \fR\&"
-Specify encrypted root partition [PARTUUID, UUID, LABEL, DEVICE]
-
-This option required if you need LUKS support
-.TP
-
-.TP
-.BR \fBluks_name=\fR"\&\fI ... \fR\&"
-Specify device mapper name
-.TP
-
-.TP
-.BR \fBluks_header=\fR"\&\fI /path/to/file \fR\&"
-Embed header into initramfs
-.TP
-
-.TP
-.BR \fBluks_keyfile=\fR"\&\fI /path/to/file \fR\&"
-Embed key into initramfs
-.TP
-
-.TP
-.BR \fBluks_discard=\fR"\&\fI {0|1} \fR\&"
-Enable TRIM requests
-.TP
-
-.TP
-.BR \fBluks_args=\fR"\&\fI ... \fR\&"
-Pass additional options to cryptsetup
-.TP
diff --git a/usr/share/man/man7/tinyramfs.cmdline.7 b/usr/share/man/man7/tinyramfs.cmdline.7
deleted file mode 100644
index 5fbd144..0000000
--- a/usr/share/man/man7/tinyramfs.cmdline.7
+++ /dev/null
@@ -1,102 +0,0 @@
-.TH tinyramfs 7 "March 2020" tinyramfs
-
-.SH NAME
-tinyramfs \- kernel command line options
-
-.SH GENERAL
-
-.TP
-.BR \fBdebug=\fR"\&\fI {0|1} \fR\&"
-Enable shell debugging
-
-This option also drop you to shell after root partition being mounted
-.TP
-
-.TP
-.BR \fBinit=\fR"\&\fI /path/to/file \fR\&"
-Specify init program
-.TP
-
-.TP
-.BR \fBroot=\fR"\&\fI ... \fR\&"
-Specify root partition [PARTUUID, UUID, LABEL, DEVICE]
-.TP
-
-.TP
-.BR \fBroot.type=\fR"\&\fI ... \fR\&"
-Specify root partition type
-.TP
-
-.TP
-.BR \fBroot.opts=\fR"\&\fI ... \fR\&"
-Specify root partition mount options (comma separated)
-.TP
-
-.SH LVM
-
-.TP
-.BR \fBlvm=\fR"\&\fI {0|1} \fR\&"
-Enable LVM support
-.TP
-
-.TP
-.BR \fBlvm.name=\fR"\&\fI ... \fR\&"
-Specify logical volume name
-.TP
-
-.TP
-.BR \fBlvm.group=\fR"\&\fI ... \fR\&"
-Specify volume group name
-.TP
-
-.TP
-.BR \fBlvm.config=\fR"\&\fI {0|1} \fR\&"
-Not implemented
-.TP
-
-.TP
-.BR \fBlvm.discard=\fR"\&\fI {0|1} \fR\&"
-Not implemented
-.TP
-
-.TP
-.BR \fBlvm.args=\fR"\&\fI ... \fR\&"
-Pass additional options to lvm
-.TP
-
-.SH LUKS
-
-.TP
-.BR \fBluks=\fR"\&\fI {0|1} \fR\&"
-Enable LUKS support
-.TP
-
-.TP
-.BR \fBluks.root=\fR"\&\fI ... \fR\&"
-Specify encrypted root partition [PARTUUID, UUID, LABEL, DEVICE]
-.TP
-
-.TP
-.BR \fBluks.name=\fR"\&\fI ... \fR\&"
-Specify device mapper name
-.TP
-
-.TP
-.BR \fBluks.header=\fR"\&\fI /path/to/file \fR\&"
-Not implemented
-.TP
-
-.TP
-.BR \fBluks.keyfile=\fR"\&\fI /path/to/file \fR\&"
-Not implemented
-.TP
-
-.TP
-.BR \fBluks.discard=\fR"\&\fI {0|1} \fR\&"
-Enable TRIM requests
-.TP
-
-.TP
-.BR \fBluks.args=\fR"\&\fI ... \fR\&"
-Pass additional options to cryptsetup
-.TP
diff --git a/usr/share/tinyramfs/device-helper b/usr/share/tinyramfs/device-helper
new file mode 100755
index 0000000..402990b
--- /dev/null
+++ b/usr/share/tinyramfs/device-helper
@@ -0,0 +1,43 @@
+#!/bin/sh -f
+#
+# create /dev/disk/by-* and /dev/mapper/* symlinks
+
+create_symlink()
+{
+    sym="$1"
+    sym="${sym%\"}"
+    sym="${sym#\"}"
+    sym="${dir}${sym}"
+
+    mkdir -p "$dir" 2> /dev/null
+    ln    -s "/dev/${MDEV}" "$sym" 2> /dev/null
+}
+
+# int main()
+{
+    [ "$MDEV" ] || exit 1
+
+    for line in $(blkid "$MDEV"); do
+        case "${line%%=*}" in
+            UUID)
+                dir="/dev/disk/by-uuid/"
+                create_symlink "${line##*=}"
+            ;;
+            LABEL)
+                dir="/dev/disk/by-label/"
+                create_symlink "${line##*=}"
+            ;;
+            PARTUUID)
+                dir="/dev/disk/by-partuuid/"
+                create_symlink "${line##*=}"
+            ;;
+        esac
+    done
+
+    [ -e "/sys/block/${MDEV}/dm/name" ] &&
+    {
+        mkdir -p /dev/mapper 2> /dev/null
+        read  -r name < "/sys/block/${MDEV}/dm/name"
+        ln    -s "/dev/${MDEV}" "/dev/mapper/${name}" 2> /dev/null
+    }
+}
diff --git a/usr/share/tinyramfs/group b/usr/share/tinyramfs/group
deleted file mode 100644
index 565203c..0000000
--- a/usr/share/tinyramfs/group
+++ /dev/null
@@ -1,14 +0,0 @@
-root:x:0:
-tty:x:5:
-dialout:x:11:
-uucp:x:14:
-kmem:x:3:
-input:x:25:
-video:x:13:
-audio:x:12:
-lp:x:10:
-disk:x:9:
-cdrom:x:16:
-tape:x:6:
-kvm:x:24:
-floppy:x:8:
diff --git a/usr/share/tinyramfs/init b/usr/share/tinyramfs/init
old mode 100644
new mode 100755
index 667bd6b..d088e2e
--- a/usr/share/tinyramfs/init
+++ b/usr/share/tinyramfs/init
@@ -1,168 +1,236 @@
-#!/sbin/busybox sh
+#!/bin/sh -ef
 #
-# tiny init script
+# tiny init
 
-panic() {
+panic()
+{
     printf "panic >> %s\n" "$1"
 
-    # TODO fix job control
-    sh
+    # see https://busybox.net/FAQ.html#job_control
+    setsid sh -c "exec sh <> /dev/${console:-console} 2>&1" || sh
 }
 
-parse_cmdline() {
-    read -r cmdline < /proc/cmdline
-    set -f && set +f -- $cmdline
+findfs()
+{
+    value=0; device=
 
-    for line in "$@"; do
-        value="${line##*=}"
+    case "${1%%=*}" in
+        /dev/*)
+            device="$1"
+        ;;
+        UUID)
+            device="/dev/disk/by-uuid/${1##*=}"
+        ;;
+        LABEL)
+            device="/dev/disk/by-label/${1##*=}"
+        ;;
+        PARTUUID)
+            device="/dev/disk/by-partuuid/${1##*=}"
+        ;;
+    esac
 
-        case "${line%%=*}" in
-            debug)        debug="$value"        ;;
-            init)         init="$value"         ;;
-            root)         root="$value"         ;;
-            root.type)    root_type="$value"    ;;
-            root.opts)    root_opts="$value"    ;;
-            lvm)          lvm="$value"          ;;
-            lvm.name)     lvm_name="$value"     ;;
-            lvm.group)    lvm_group="$value"    ;;
-            lvm.args)     lvm_args="$value"     ;;
-            luks)         luks="$value"         ;;
-            luks.root)    luks_root="$value"    ;;
-            luks.name)    luks_name="$value"    ;;
-            luks.discard) luks_discard="$value" ;;
-            luks.args)    luks_args="$value"    ;;
-            # TODO implement
-            #lvm.discard)  ;;
-            #lvm.config)   ;;
-            #luks.header)  ;;
-            #luks.keyfile) ;;
-        esac
+    # avoid race condition
+    while [ ! -e "$device" ]; do
+        value=$(( value + 1 ))
+        [ "$value" = 15 ] && panic "failed to lookup partition"
+        sleep 1
     done
 }
 
-prepare_environment() {
-    /sbin/busybox --install -s
+prepare_environment()
+{
+    . /etc/config
 
-    . /config || panic "failed to source config"
+    export \
+        SHELL=/bin/sh \
+        TERM=linux \
+        HOME=/root \
+        PATH=/bin:/sbin:/usr/bin:/usr/sbin \
+        PS1="# " \
+        LC_ALL=C \
+        LANG=C \
+        OLD_IFS="$IFS"
+
+    # fix for ubase mount
+    :> /etc/fstab
 
     mount -t proc     -o nosuid,noexec,nodev     proc /proc
     mount -t sysfs    -o nosuid,noexec,nodev     sys  /sys
-    mount -t tmpfs    -o mode=0755,nosuid,nodev  run  /run
-    mount -t devtmpfs -o mode=0755,noexec,nosuid dev  /dev
-
-    mkdir -pm 0755 /run/cryptsetup /run/lvm /dev/pts /dev/shm
-
-    mount -t devpts -o gid=5,mode=620,noexec,nosuid  devpts /dev/pts
-    mount -t tmpfs  -o mode=1777,noexec,nosuid,nodev shm    /dev/shm
+    mount -t devtmpfs -o nosuid,noexec,mode=0755 dev  /dev
 
     ln -s /proc/self/fd   /dev/fd
     ln -s /proc/self/fd/0 /dev/stdin
     ln -s /proc/self/fd/1 /dev/stdout
     ln -s /proc/self/fd/2 /dev/stderr
+
+    trap 'panic "something went wrong"' EXIT
 }
 
-setup_devmgr() {
+parse_cmdline()
+{
+    [ "$break" = cmdline ] && panic "break before parse cmdline"
+
+    read -r cmdline < /proc/cmdline
+
+    for line in $cmdline; do
+        case "$line" in
+            debug | debug=1)
+                set -x
+            ;;
+            *.*)
+                # TODO implement backward compatibilty with dracut, mkinitcpio, etc
+                : no operation
+            ;;
+            *=*)
+                export "$line"
+            ;;
+            *)
+                export "${line}=1"
+            ;;
+        esac
+    done
+}
+
+setup_devmgr()
+{
+    [ "$break" = devmgr ] && panic "break before setup device manager"
+
     case "$devmgr" in
         udev)
             udevd -d -N never
             udevadm trigger -c add -t subsystems
             udevadm trigger -c add -t devices
             udevadm settle
-            ;;
+        ;;
         mdev)
-            mdev -df &
+            mdev -df 2> /dev/null & mdev_pid="$!"
 
-            find /sys -name modalias -type f -exec sort -u {} + |
-                xargs modprobe -ba
-            ;;
+            [ "$monolith" != 1 ] &&
+            {
+                set -- $(find /sys -name modalias -type f -exec sort -u {} +)
+                modprobe -a "$@" 2> /dev/null
+            }
+        ;;
         mdevd)
-            mdevd &
+            mdevd 2> /dev/null & mdevd_pid="$!"
             mdevd-coldplug
-            ;;
+        ;;
     esac
 }
 
-findfs_sh() {
-    value="${1##*=}"
+unlock_luks()
+{
+    [ "$break" = luks ] && panic "break before unlock LUKS"
 
-    case "${1%%=*}" in
-        LABEL)    device="/dev/disk/by-label/${value}"    ;;
-        UUID)     device="/dev/disk/by-uuid/${value}"     ;;
-        PARTUUID) device="/dev/disk/by-partuuid/${value}" ;;
-        /dev/*)   device="$1"                             ;;
-    esac
+    { IFS=,; set -- $luks_opts; IFS="$OLD_IFS"; }
 
-    # avoid race condition
-    while [ ! -e "$device" ]; do
-        sleep 0.5
-        [ "$increment" ] || increment=0
-        increment=$(( increment + 1 ))
-        [ "$increment" = 10 ] && panic "failed to lookup partition"
+    for opt; do
+        case "$opt" in
+            discard | discard=1)
+                luks_discard="--allow-discards"
+            ;;
+            header=*)
+                luks_header="--${opt}"
+            ;;
+            name=*)
+                luks_name="${opt##*=}"
+            ;;
+            key=*)
+                luks_key="-d ${opt##*=}"
+            ;;
+        esac
     done
 
-    printf "%s\n" "$device"
+    findfs "$luks_root"
+
+    set -- "--disable-locks" "$luks_key" "$luks_discard" "$luks_header" "$device" "${luks_name:-luks-${device##*/}}"
+    cryptsetup open $@ || panic "failed to unlock LUKS"
 }
 
-unlock_luks() {
-    [ "$luks_discard" = 1   ] && luks_args="--allow-discards $luks_args"
-    [ -f /root/luks_header  ] && luks_args="--header=/root/luks_header $luks_args"
-    [ -f /root/luks_keyfile ] && luks_args="--key-file=/root/luks_keyfile $luks_args"
+trigger_lvm()
+{
+    [ "$break" = lvm ] && panic "break before trigger LVM"
 
-    cryptsetup $luks_args \
-               luksOpen \
-               $(findfs_sh "$luks_root") \
-               ${luks_name:-luks_root} ||
-               panic "failed to unlock luks container"
-}
+    { IFS=,; set -- $lvm_opts; IFS="$OLD_IFS"; }
+
+    for opt; do
+        case "$opt" in
+            discard | discard=1)
+                lvm_discard="--config=devices{issue_discards=1}"
+            ;;
+            config=0)
+                :> /etc/lvm/lvm.conf
+            ;;
+            group=*)
+                lvm_group="${opt##*=}"
+            ;;
+            name=*)
+                lvm_name="/${opt##*=}"
+            ;;
+            tag=*)
+                lvm_tag="@${opt##*=}"
+            ;;
+        esac
+    done
+
+    set -- "--sysinit" "-qq" "-ay" "$lvm_discard"
 
-trigger_lvm() {
     if [ "$lvm_group" ] && [ "$lvm_name" ]; then
-        lvm lvchange $lvm_args --sysinit -q -a y "${lvm_group}/${lvm_name}" > /dev/null
+        lvchange $@ "${lvm_group}${lvm_name}"
     elif [ "$lvm_group" ]; then
-        lvm vgchange $lvm_args --sysinit -q -a y "$lvm_group" > /dev/null
+        vgchange $@ "$lvm_group"
+    elif [ "$lvm_tag" ]; then
+        lvchange $@ "$lvm_tag"
     else
-        lvm vgchange $lvm_args --sysinit -q -a y > /dev/null
+        vgchange $@
     fi
 }
 
-mount_rootfs() {
-    mount ${root_type:+-t $root_type} \
-          ${root_opts:+-o $root_opts} \
-          $(findfs_sh "$root") \
-          /mnt/root ||
-          panic "failed to mount rootfs"
+mount_root()
+{
+    [ "$break" = root ] && panic "break before mount root"
+
+    findfs "$root"
+
+    set -- "${root_type:+-t $root_type}" "${root_opts:+-o $root_opts}" "$device" "/mnt/root"
+    mount $@ || panic "failed to mount root"
 }
 
-cleanup() {
+cleanup()
+{
+    [ "$break" = cleanup ] && panic "break before cleanup"
+
     case "$devmgr" in
         udev)  udevadm control -e ;;
-        mdev)  killall mdev       ;;
-        mdevd) killall mdevd      ;;
+        mdev)  kill "$mdev_pid"   ;;
+        mdevd) kill "$mdevd_pid"  ;;
     esac
 
-    umount /dev /sys /proc
+    # temporary workaround until util-linux mount implements 'mount -o move'
+    # see https://github.com/karelzak/util-linux/issues/997
+    for dir in dev sys proc; do
+        mount -o move "$dir" "/mnt/root/${dir}" || mount --move "$dir" "/mnt/root/${dir}"
+    done
 }
 
-boot_system() {
-    exec switch_root \
-         /mnt/root \
-         ${init:-/sbin/init} ||
-         panic "failed to boot system"
+boot_system()
+{
+    [ "$break" = boot ] && panic "break before boot system"
+
+    set -- "/mnt/root" "${init:-/sbin/init}"
+    exec switch_root $@ 2> /dev/null || panic "failed to boot system"
 }
 
-prepare_environment
-parse_cmdline
-[ "$debug" = 1 ] && set -x
-setup_devmgr
+# int main()
+{
+    prepare_environment
+    parse_cmdline
+    setup_devmgr
 
-# TODO handle situations when LUKS on LVM
-[ "$luks" =  1 ] &&
-    command -v cryptsetup > /dev/null 2>&1 && unlock_luks
+    [ "$luks" = 1 ] && unlock_luks
+    [ "$lvm"  = 1 ] && trigger_lvm
 
-[ "$lvm"  =  1 ] &&
-    command -v lvm        > /dev/null 2>&1 && trigger_lvm
-
-mount_rootfs
-[ "$debug" = 1 ] && panic "dropping to shell"
-cleanup
-boot_system
+    mount_root
+    cleanup
+    boot_system
+}
diff --git a/usr/share/tinyramfs/mdev.conf b/usr/share/tinyramfs/mdev.conf
deleted file mode 100644
index 342fd14..0000000
--- a/usr/share/tinyramfs/mdev.conf
+++ /dev/null
@@ -1,96 +0,0 @@
-# Copyright (c) 2012-2019, Piotr Karbowski <piotr.karbowski@gmail.com>
-# All rights reserved.
-#
-# Redistribution and use in source and binary forms, with or without modification, are
-# permitted provided that the following conditions are met:
-#
-#    * Redistributions of source code must retain the above copyright notice, this list
-#      of conditions and the following disclaimer.
-#    * Redistributions in binary form must reproduce the above copyright notice, this list
-#      of conditions and the following disclaimer in the documentation and/or other
-#      materials provided with the distribution.
-#    * Neither the name of the Piotr Karbowski nor the names of its contributors may be
-#      used to endorse or promote products derived from this software without specific
-#      prior written permission.
-#
-# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
-# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
-# MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
-# THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
-# OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
-# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
-# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE US
-# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-# mdev-like-a-boss
-
-# Syntax:
-# [-]devicename_regex user:group mode [=path]|[>path]|[!] [@|$|*cmd args...]
-# [-]$ENVVAR=regex    user:group mode [=path]|[>path]|[!] [@|$|*cmd args...]
-# [-]@maj,min[-min2]  user:group mode [=path]|[>path]|[!] [@|$|*cmd args...]
-#
-# [-]: do not stop on this match, continue reading mdev.conf
-# =: move, >: move and create a symlink
-# !: do not create device node
-# @|$|*: run cmd if $ACTION=remove, @cmd if $ACTION=add, *cmd in all cases
-
-# support module loading on hotplug
-$MODALIAS=.*    0:0 660 @modprobe -b "$MODALIAS"
-
-# null may already exist; therefore ownership has to be changed with command
-null        0:0 666 @chmod 666 $MDEV
-zero        0:0 666
-full        0:0 666
-random      0:0 444
-urandom     0:0 444
-hwrandom    0:0 444
-grsec       0:0 660
-kmem        0:0 640
-mem         0:0 640
-port        0:0 640
-# console may already exist; therefore ownership has to be changed with command
-console     0:5 600 @chmod 600 $MDEV
-ptmx        0:5 666
-pty.*       0:5 660
-
-# typical devices
-tty         0:5 666
-tty[0-9]*   0:5 660
-vcsa*[0-9]* 0:5 660
-ttyS[0-9]*  0:14 660
-
-# block devices
-ram([0-9]*)        0:9 660 >rd/%1
-loop([0-9]+)       0:9 660 >loop/%1
-sr[0-9]*           0:16 660 @ln -sf $MDEV cdrom
-fd[0-9]*           0:8 660
-SUBSYSTEM=block;.* 0:9 660 */lib/mdev/storage-device
-
-# raid controllers
-cciss!(.*)  0:9 660 =cciss/%1
-ida!(.*)    0:9 660 =ida/%1
-rd!(.*)     0:9 660 =rd/%1
-
-# graphics
-card[0-9]   0:13 660 =dri/
-agpgart     0:0 660 >misc/
-psaux       0:0 660 >misc/
-rtc         0:0 664 >misc/
-
-# input stuff
-SUBSYSTEM=input;.* 0:25 660
-
-# drm etc
-dri/.*      0:13 660
-
-# don't create old usbdev* devices.
-usbdev[0-9].[0-9]* 0:0 660 !
-
-# stop creating x:x:x:x which looks like /dev/dm-*
-[0-9]+\:[0-9]+\:[0-9]+\:[0-9]+ 0:0 660 !
-
-# /dev/cpu support.
-microcode       0:0 600 =cpu/
-cpu([0-9]+)     0:0 600 =cpu/%1/cpuid
-msr([0-9]+)     0:0 600 =cpu/%1/msr
diff --git a/usr/share/tinyramfs/passwd b/usr/share/tinyramfs/passwd
deleted file mode 100644
index fd28f7b..0000000
--- a/usr/share/tinyramfs/passwd
+++ /dev/null
@@ -1,2 +0,0 @@
-root:x:0:0::/root:/bin/sh
-nobody:x:99:99::/:/bin/false
diff --git a/usr/share/tinyramfs/storage-device b/usr/share/tinyramfs/storage-device
deleted file mode 100644
index 3f77fef..0000000
--- a/usr/share/tinyramfs/storage-device
+++ /dev/null
@@ -1,133 +0,0 @@
-#!/bin/sh
-# Copyright (c) 2012-2019, Piotr Karbowski <piotr.karbowski@gmail.com>
-# All rights reserved.
-#
-# Redistribution and use in source and binary forms, with or without modification, are
-# permitted provided that the following conditions are met:
-#
-#    * Redistributions of source code must retain the above copyright notice, this list
-#      of conditions and the following disclaimer.
-#    * Redistributions in binary form must reproduce the above copyright notice, this list
-#      of conditions and the following disclaimer in the documentation and/or other
-#      materials provided with the distribution.
-#    * Neither the name of the Piotr Karbowski nor the names of its contributors may be
-#      used to endorse or promote products derived from this software without specific
-#      prior written permission.
-#
-# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
-# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
-# MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
-# THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
-# OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
-# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
-# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE US
-# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-# This script meant to create /dev/disk/by-* and /dev/mapper/* symlinks.
-# and remove them after storage device is removed.
-# the /dev/disk/by-* handling based on the idea and proof of concept from BitJam.
-
-# debug
-#exec >> /run/debug-mdev 2>&1
-#set -x
-#echo '### ENV:'
-#env
-#echo '### CODE:'
-#
-
-umask 077
-
-storage_dir="/tmp/.mdev-like-a-boss"
-[ -d "$storage_dir" ] || mkdir "$storage_dir"
-
-[ "$MDEV" ] || exit 2
-
-create_uuid_label_symlink() {
-    target_dir="/dev/disk/by-${1}"
-    target_symlink="${target_dir}/${2}"
-    [ -e "$target_symlink" ] && return
-    mkdir -p "$target_dir"
-    ln -sf "/dev/${MDEV}" "$target_symlink"
-    printf "%s\n" "$target_symlink" > "${storage_dir}/storage_symlink_${1}_${MDEV}"
-}
-
-add_symlinks() {
-    # Skip temp cryptsetup nodes.
-    case "$MDEV" in
-        dm-[0-9]*)
-            case $(cat "/sys/block/${MDEV}/dm/name") in
-                temporary-cryptsetup-[0-9]*)
-                    return 0
-                    ;;
-            esac
-            ;;
-    esac
-
-    if command -v blkid > /dev/null 2>&1; then
-        blkid_output=$(blkid "/dev/${MDEV}")
-        eval "${blkid_output#*: }"
-
-        [ "$UUID" ] && create_uuid_label_symlink uuid "$UUID"
-        [ "$LABEL" ] && create_uuid_label_symlink label "$LABEL"
-        [ "$PARTUUID" ] && create_uuid_label_symlink partuuid "$PARTUUID"
-    fi
-
-    if [ -f "/sys/block/${MDEV}/dm/name" ]; then
-        [ -d /dev/mapper ] || mkdir /dev/mapper
-        if ! [ -c /dev/mapper/control ]; then
-            while read -r dm; do
-                [ "${dm#* }" = device-mapper ] && {
-                    mknod /dev/mapper/control c 10 "${dm% *}" || exit 1
-                    break
-                }
-            done < /proc/misc
-        fi
-
-        dmname=$(cat "/sys/block/${MDEV}/dm/name")
-        if [ "$dmname" ]; then
-            target_symlink="/dev/mapper/${dmname}"
-            [ -e "$target_symlink" ] && return
-            ln -sf "/dev/${MDEV}" "$target_symlink"
-            printf "%s\n" "$target_symlink" > "${storage_dir}/storage_symlink_mapper_${MDEV}"
-        fi
-    fi
-}
-
-set_readahead() {
-    read_ahead_kb_control="/sys/class/block/${MDEV}/queue/read_ahead_kb"
-    new_read_ahead_kb="2048"
-
-    if [ -f "$read_ahead_kb_control" ]; then
-        read_ahead_kb=$(cat "$read_ahead_kb_control")
-        if [ "$read_ahead_kb" -lt "$new_read_ahead_kb" ]; then
-            logger -t mdev "Changing $MDEV read_ahead_kb from $read_ahead_kb to $new_read_ahead_kb"
-            printf "%s" "$new_read_ahead_kb" > "$read_ahead_kb_control"
-        fi
-    fi
-}
-
-drop_symlinks() {
-    for type in uuid label mapper; do
-        [ -f "${storage_dir}/storage_symlink_${type}_${MDEV}" ] || continue
-        target_symlink=$(cat "${storage_dir}/storage_symlink_${type}_${MDEV}" 2> /dev/null)
-        [ "$target_symlink" ] || continue
-
-        target_symlink_device=$(readlink "$target_symlink")
-        if [ "$target_symlink_device" = "/dev/${MDEV}" ]; then
-            rm "$target_symlink"
-        fi
-
-        rm "${storage_dir}/storage_symlink_${type}_${MDEV}"
-    done
-}
-
-case "$ACTION" in
-    add | "")
-        add_symlinks
-        set_readahead
-        ;;
-    remove)
-        drop_symlinks
-        ;;
-esac