diff --git a/config/functions b/config/functions
index 1bc1991d86..46e7f1da0c 100644
--- a/config/functions
+++ b/config/functions
@@ -775,6 +775,11 @@ do_autoreconf() {
   fi
 }
 
+# True if this is a sequential build, false if multithreaded
+is_sequential_build() {
+  [ "${MTWITHLOCKS}" != "yes" ] && return 0 || return 1
+}
+
 
 ### PACKAGE HELPERS ###
 # get variable ($2) for package ($1).
@@ -1380,48 +1385,43 @@ enable_service() {
 
 
 ### MULTI-THREADED FUNCTION HELPERS ###
-# Test MTWITHLOCKS so that these functions are a no-op during non-multithreaded builds.
+# flocks: 94 (pkg_lock_status)
+#         95 (scripts/pkgbuild)
+#         96 (acquire_exclusive_lock)
+#         97 (acquire_update_lock)
+#         98 (pkg_lock)
+#         99 (scripts/get)
 
-# Prevent concurrent modifications to a package (unpack) or
-# package:target (install/build).
+# Test build type so that these functions are a no-op during non-multithreaded builds.
+
+# Prevent concurrent modifications to a package during certain activities.
+# With dynamic scheduling we now only need to acquire the lock
+# during unpack and reconf, all other activities do not need to acquire a
+# lock as there should be no concurrent access however the existing code path
+# potentially generates useful logging for minimal cost so keep it.
 #
 # If a package is already locked and the owner is ourselves
 # then assume we already have the required lock.
 pkg_lock() {
-  [ "${MTWITHLOCKS}" != "yes" ] && return 0
+  is_sequential_build && return 0
 
   local pkg="$1" task="$2" parent_pkg="$3"
   local this_job="${MTJOBID}"
   local lock_job lock_seq lock_task lock_pkg locked=no idwidth
-  local fail_seq
 
-  exec 98>"${THREAD_CONTROL}/locks/${pkg}.${task}"
-  while [ : ]; do
-    read -r lock_job lock_seq lock_task lock_pkg <<<$(cat "${THREAD_CONTROL}/locks/${pkg}.${task}.owner" 2>/dev/null)
-    [ -n "${lock_job}" ] && break
-    flock --wait 1 --exclusive 98 && locked=yes && break
-  done
+  if [ "${task}" = "unpack" -o "${task}" = "reconf" ]; then
+    exec 98>"${THREAD_CONTROL}/locks/${pkg}.${task}"
+    while [ : ]; do
+      read -r lock_job lock_seq lock_task lock_pkg <<<$(cat "${THREAD_CONTROL}/locks/${pkg}.${task}.owner" 2>/dev/null)
+      [ -n "${lock_job}" ] && break
+      flock --wait 1 --exclusive 98 && locked=yes && break
+    done
 
-  if [ "${locked}" = "no" -a "${lock_job}/${lock_seq}" != "${this_job}/${PARALLEL_SEQ}" ]; then
-    [ "${THREADCOUNT}" = "0" ] && idwidth=${#MTMAXJOBS} || idwidth=2
-    pkg_lock_status "STALLED" "${parent_pkg}" "${task}" "$(printf "waiting on [%0*d] %s %s" ${idwidth} ${lock_job} "${lock_task}" "${lock_pkg}")"
-    flock --exclusive 98
-  fi
-
-  # As we now have the lock, if .failed still exists then a previous process must have failed
-  if [ -f "${THREAD_CONTROL}/locks/${pkg}.${task}.failed" ]; then
-    fail_seq="$(< "${THREAD_CONTROL}/locks/${pkg}.${task}.failed")"
-    print_color CLR_ERROR "FAILURE: ${pkg}.${task}.failed exists, a previous dependency process has failed (seq: ${fail_seq})\n"
-    if [ -d "${THREAD_CONTROL}/logs" ]; then
-cat <<EOF
-
-The following logs for this failure are available:
-  stdout: ${THREAD_CONTROL}/logs/${fail_seq}/stdout
-  stderr: ${THREAD_CONTROL}/logs/${fail_seq}/stderr
-
-EOF
+    if [ "${locked}" = "no" -a "${lock_job}/${lock_seq}" != "${this_job}/${PARALLEL_SEQ}" ]; then
+      [ "${THREADCOUNT}" = "0" ] && idwidth=${#MTMAXJOBS} || idwidth=2
+      pkg_lock_status "STALLED" "${parent_pkg}" "${task}" "$(printf "waiting on [%0*d] %s %s" ${idwidth} ${lock_job} "${lock_task}" "${lock_pkg}")"
+      flock --exclusive 98
     fi
-    return 1
   fi
 
   pkg_lock_status "LOCKED" "${pkg}" "${task}"
@@ -1429,7 +1429,7 @@ EOF
 
 # Log additional information for a locked package.
 pkg_lock_status() {
-  [ "${MTWITHLOCKS}" != "yes" ] && return 0
+  is_sequential_build && return 0
 
   local status="$1" pkg="$2" task="$3" msg="$4"
   local this_job="${MTJOBID}" line idwidth
@@ -1439,6 +1439,12 @@ pkg_lock_status() {
   (
     flock --exclusive 94
 
+    # Write the configured number of slots to history to improve accuracy of later analysis
+    if [ ! -f "${THREAD_CONTROL}/history" ]; then
+      printf "%s: <%06d> [%0*d/%0*d] %-7s %-7s %s %s\n" \
+        "$(date +%Y-%m-%d\ %H:%M:%S.%N)" $$ ${idwidth} 0 ${#MTMAXJOBS} 0 "IDLE" "config" "info" "slots=${MTMAXSLOT};jobs=${MTMAXJOBS}" >>"${THREAD_CONTROL}/history"
+    fi
+
     printf -v line "%s: <%06d> [%0*d/%0*d] %-7s %-7s %-35s" \
       "$(date +%Y-%m-%d\ %H:%M:%S.%N)" $$ ${idwidth} ${this_job} ${#MTMAXJOBS} ${PARALLEL_SEQ:-0} "${status}" "${task}" "${pkg}"
     [ -n "${msg}" ] && line+=" (${msg})"
@@ -1451,31 +1457,29 @@ pkg_lock_status() {
   ) 94>"${THREAD_CONTROL}/locks/.history"
 
   if [ "${status}" = "LOCKED" ]; then
-    echo "${PARALLEL_SEQ}" > "${THREAD_CONTROL}/locks/${pkg}.${task}.failed"
     echo "${this_job} ${PARALLEL_SEQ} ${task} ${pkg}" >"${THREAD_CONTROL}/locks/${pkg}.${task}.owner"
   elif [ "${status}" = "UNLOCK" ]; then
     rm "${THREAD_CONTROL}/locks/${pkg}.${task}.owner"
-    rm "${THREAD_CONTROL}/locks/${pkg}.${task}.failed"
   fi
 
   return 0
 }
 
 update_dashboard() {
-  [ "${MTWITHLOCKS}" != "yes" ] && return 0
+  is_sequential_build && return 0
 
   local status="$1" pkg="$2" task="$3" msg="$4"
-  local line sedline preamble num elapsed projdevarch
+  local line preamble num elapsed projdevarch
   local boldred boldgreen boldyellow endcolor idwidth
 
-  sedline=$((MTJOBID + 2))
+  [ "${THREADCOUNT}" = "0" ] && idwidth=${#MTMAXSLOT} || idwidth=2
 
-  [ "${THREADCOUNT}" = "0" ] && idwidth=${#MTMAXJOBS} || idwidth=2
-
-  num=$(< "${THREAD_CONTROL}/status.max")
-  if [ ${num} -lt ${sedline} ]; then
-    echo ${sedline} >"${THREAD_CONTROL}/status.max"
-    for i in $(seq $((num + 1)) ${sedline}); do echo "" >>"${THREAD_CONTROL}/status"; done
+  if [ ! -s ${THREAD_CONTROL}/status ]; then
+    echo "" >"${THREAD_CONTROL}/status"
+    echo "" >>"${THREAD_CONTROL}/status"
+    for i in $(seq 1 $((MTMAXSLOT))); do
+      printf "[%0*d/%0*d] %-7s\n" ${idwidth} ${i} ${#MTMAXJOBS} 0 "IDLE" >>"${THREAD_CONTROL}/status"
+    done
   fi
 
   num=$(< "${THREAD_CONTROL}/progress.prev")
@@ -1506,13 +1510,13 @@ update_dashboard() {
   printf -v line "[%0*d\/%0*d] %b%-7s%b %-7s %-35s" ${idwidth} ${MTJOBID} ${#MTMAXJOBS} ${PARALLEL_SEQ:-0} "${color}" "${status//\//\\/}" "${endcolor}" "${task}" "${pkg}"
   [ -n "${msg}" ] && line+=" ${msg//\//\\/}"
 
-  sed -e "1s/.*/${preamble}/;${sedline}s/.*/${line}/" -i "${THREAD_CONTROL}/status"
+  sed -e "1s/.*/${preamble}/;$((MTJOBID + 2))s/.*/${line}/" -i "${THREAD_CONTROL}/status"
 }
 
 # Thread concurrency helpers to avoid concurrency issues with some code,
 # eg. when Python installs directly into $TOOLCHAIN.
 acquire_exclusive_lock() {
-  [ "${MTWITHLOCKS}" != "yes" ] && return 0
+  is_sequential_build && return 0
 
   local pkg="$1" task="$2" lockfile="${3:-global}"
   local this_job="${MTJOBID}"
@@ -1537,7 +1541,7 @@ acquire_exclusive_lock() {
 }
 
 release_exclusive_lock() {
-  [ "${MTWITHLOCKS}" != "yes" ] && return 0
+  is_sequential_build && return 0
 
   local pkg="$1" task="$2" lockfile="${3:-global}"
 
@@ -1557,6 +1561,20 @@ exec_thread_safe() {
   return ${result}
 }
 
+# A lightweight target specific lock (eg. image, sysroot)
+acquire_update_lock() {
+  is_sequential_build && return 0
+
+  exec 97>"${THREAD_CONTROL}/locks/.update.${1}"
+  flock --exclusive 97
+}
+
+release_update_lock() {
+  is_sequential_build && return 0
+
+  flock --unlock 97 2>/dev/null
+}
+
 # Use distribution functions if any
 if [ -f "distributions/$DISTRO/config/functions" ]; then
   . distributions/$DISTRO/config/functions
diff --git a/config/multithread b/config/multithread
index 4b7822f8ff..f5ec0b025b 100644
--- a/config/multithread
+++ b/config/multithread
@@ -1,162 +1,62 @@
 # SPDX-License-Identifier: GPL-2.0
 # Copyright (C) 2019-present Team LibreELEC (https://libreelec.tv)
 
-THREADCOUNT=${THREADCOUNT:-100%}
-
-# This function is passed a list of package.mk paths to be processed.
-# Each package.mk is sourced with relevant variables output in JSON format.
-json_worker() {
-  local packages="$@"
-  local pkgpath hierarchy exited
-
-  exit() { exited=1; }
-
-  . config/options ""
-
-  for pkgpath in ${packages}; do
-    pkgpath="${pkgpath%%@*}"
-
-    exited=0
-    if ! source_package "${pkgpath}/package.mk" &>/dev/null; then
-      unset -f exit
-      die "$(print_color CLR_ERROR "FAILURE: sourcing package ${pkgpath}/package.mk")"
-    fi
-
-    [ ${exited} -eq 1 ] && continue
-
-    [[ ${pkgpath} =~ ^${ROOT}/${PACKAGES}/ ]] && hierarchy="global" || hierarchy="local"
-
-    cat <<EOF
-  {
-    "name": "${PKG_NAME}",
-    "hierarchy": "${hierarchy}",
-    "section": "${PKG_SECTION}",
-    "bootstrap": "${PKG_DEPENDS_BOOTSTRAP}",
-    "init": "${PKG_DEPENDS_INIT}",
-    "host": "${PKG_DEPENDS_HOST}",
-    "target": "${PKG_DEPENDS_TARGET}"
-  },
-EOF
-  done
-}
-export -f json_worker
-
-# This function is passed the build instruction for a single job.
-# The function will run either "build <package>" or "install <package>".
-# ${slot} is the job slot number, ie. 1-8 when THREADCOUNT=8.
-# ${job} is the sequence within the total number of ${jobs}.
-package_worker() {
-  local slot=$1 job=$2 jobs=$3 args="$4"
-  local task pkgname result status
-  local addon istarget isaddon
-
-  export MTJOBID=${slot} MTMAXJOBS=${jobs}
-
-  read -r task pkgname <<< "${args}"
-
-  . config/options "${pkgname}"
-
-  [ ! -f "${THREAD_CONTROL}/parallel.pid" ] && echo "${PARALLEL_PID}" >"${THREAD_CONTROL}/parallel.pid"
-
-  ${SCRIPTS}/${task} ${pkgname} 2>&1 && result=0 || result=1
-
-  [[ ${pkgname} =~ :target$ || "${pkgname//:/}" = "${pkgname}" ]] && istarget="yes" || istarget="no"
-
-  [[ "${MTADDONBUILD}" = "yes" && ( "${PKG_IS_ADDON}" = "yes" || "${PKG_IS_ADDON}" = "embedded" ) ]] && isaddon="yes" || isaddon="no"
-
-  if [ "${isaddon}" = "yes" -a "${istarget}" = "yes" ]; then
-    if [ ${result} -eq 0 ]; then
-      ${SCRIPTS}/install_addon ${pkgname} 2>&1 && result=0 || result=1
-    fi
-
-    if [ ${result} -ne 0 ]; then
-      if [ -d "${THREAD_CONTROL}/logs" ]; then
-        echo "${PKG_NAME} ${THREAD_CONTROL}/logs/${job}/stdout" >>"${THREAD_CONTROL}/addons.failed"
-      else
-        echo "${PKG_NAME}" >>"${THREAD_CONTROL}/addons.failed"
-      fi
-    fi
-  fi
-
-  (
-    flock --exclusive 95
-    [ ${result} -eq 0 ] && status="DONE" || status="FAIL"
-    num=$(< "${THREAD_CONTROL}/progress")
-    mv "${THREAD_CONTROL}/progress" "${THREAD_CONTROL}/progress.prev"
-    num=$((num + 1))
-    echo ${num} >"${THREAD_CONTROL}/progress"
-    printf "[%0*d/%0*d] [%-4s] %-7s %s\n" ${#jobs} ${num} ${#jobs} ${jobs} "${status}" "${task}" "${pkgname}" >&2
-  ) 95>"${THREAD_CONTROL}/locks/.progress"
-
-  if [ ${result} -eq 0 ]; then
-    pkg_lock_status "IDLE"
-  else
-    pkg_lock_status "FAILED" "${pkgname}" "${task}"
-
-    print_color CLR_ERROR "FAILURE: $SCRIPTS/${task} ${pkgname} has failed!\n"
-
-    if [ -d "${THREAD_CONTROL}/logs" ]; then
-      cat >&2 <<EOF
-
-The following logs for this failure are available:
-  stdout: ${THREAD_CONTROL}/logs/${job}/stdout
-  stderr: ${THREAD_CONTROL}/logs/${job}/stderr
-
-EOF
-    fi
-  fi
-
-  return ${result}
-}
-export -f package_worker
+THREADCOUNT=${THREADCOUNT:-$(nproc)}
 
 start_multithread_build() {
-  local singlethread buildopts result=0
+  local buildopts result=0
 
   # init thread control folder
   rm -rf "${THREAD_CONTROL}"
   mkdir -p "${THREAD_CONTROL}/locks"
   echo -1 >"${THREAD_CONTROL}/progress.prev"
   echo 0 >"${THREAD_CONTROL}/progress"
-  echo 0 >"${THREAD_CONTROL}/status.max"
   touch "${THREAD_CONTROL}/status"
 
   # Increase file descriptors if building one thread/package
   [ "${THREADCOUNT}" = "0" ] && ulimit -n ${ULIMITN:-10240}
 
-  # Bootstrap GNU parallel
-  MTWITHLOCKS=no $SCRIPTS/build parallel:host 2>&1 || die "Unable to bootstrap parallel package"
-
-  # determine number of available slots for the given THREADCOUNT - optimise logging for single threaded builds
-  [ $(seq 1 32 | ${TOOLCHAIN}/bin/parallel --plain --no-notice --max-procs ${THREADCOUNT} echo {%} | sort -n | tail -1) -eq 1 ] && singlethread=yes || singlethread=no
-
   # create a single log file by default for a single threaded build (or the builder is a masochist)
-  if [ "${singlethread}" = "yes" -a "${ONELOG,,}" != "no" ] || [ "${ONELOG,,}" = "yes" ]; then
-    buildopts+=" --ungroup"
+  if [ ${THREADCOUNT} -eq 1 -a "${ONELOG,,}" != "no" ] || [ "${ONELOG,,}" = "yes" ]; then
+    buildopts+=" --no-log-burst"
   else
     mkdir -p "${THREAD_CONTROL}/logs"
-    buildopts+=" --group --results ${THREAD_CONTROL}/logs/{#}/"
+    buildopts+=" --log-burst"
   fi
+  buildopts+=" --log-combine ${LOGCOMBINE:-always}"
 
   # When building addons, don't halt on error - keep building all packages/addons
-  [ "${MTADDONBUILD}" = "yes" ] && buildopts+=" --halt never" || buildopts+=" --halt now,fail=1"
+  [ "${MTADDONBUILD}" = "yes" ] && buildopts+=" --continue-on-error" || buildopts+=" --halt-on-error"
+
+  [ "${MTVERBOSE}" = "yes" ] && buildopts+=" --verbose"
+  [ "${MTDEBUG}" = "yes" ] && buildopts+=" --debug"
+  if [ "${DISABLE_COLORS}" = "yes" ]; then
+    buildopts+=" --colors=never"
+  else
+    buildopts+=" --colors=${MTCOLORS:-auto}"
+  fi
+
+  buildopts+=" --stats-interval ${MTINTERVAL:-60}"
 
   # pipefail: return value of a pipeline is the value of the last (rightmost) command to exit with a non-zero status
   set -o pipefail
 
-  cat ${_CACHE_PACKAGE_GLOBAL} ${_CACHE_PACKAGE_LOCAL} | \
-    ${TOOLCHAIN}/bin/parallel --plain --no-notice --max-args 30 --halt now,fail=1 json_worker | \
-    ${SCRIPTS}/genbuildplan.py --no-reorder --show-wants --build ${@} > "${THREAD_CONTROL}"/plan || result=1
+  ${SCRIPTS}/pkgjson | ${SCRIPTS}/genbuildplan.py --show-wants --with-json "${THREAD_CONTROL}"/plan.json \
+      --build ${@} > "${THREAD_CONTROL}"/plan || result=1
 
   if [ ${result} -eq 0 ]; then
     save_build_config
 
-    cat "${THREAD_CONTROL}"/plan | awk '{print $1 " " $2}' | \
-      MTBUILDSTART=$(date +%s) MTWITHLOCKS=yes ${TOOLCHAIN}/bin/parallel \
-        --plain --no-notice --max-procs ${THREADCOUNT} --joblog="${THREAD_CONTROL}/joblog" --plus ${buildopts} \
-        package_worker {%} {#} {##} {} || result=1
+    # export the following vars so that they will be available to subprocesses of pkgbuilder.py
+    export ROOT SCRIPTS THREAD_CONTROL
 
-    [ -f "${THREAD_CONTROL}"/history ] && echo && cat "${THREAD_CONTROL}"/history | ${ROOT}/tools/mtstats.py
+    MTBUILDSTART=$(date +%s) MTWITHLOCKS=yes ${SCRIPTS}/pkgbuilder.py \
+        --plan "${THREAD_CONTROL}"/plan.json \
+        --joblog "${THREAD_CONTROL}"/joblog \
+        --loadstats "${THREAD_CONTROL}"/loadstats \
+        --max-procs ${THREADCOUNT} ${buildopts} || result=1
+
+    [ ${result} -eq 0 -a -f "${THREAD_CONTROL}"/history ] && echo && cat "${THREAD_CONTROL}"/history | ${ROOT}/tools/mtstats.py
 
     rm -f "${THREAD_CONTROL}/parallel.pid"
   fi
diff --git a/packages/addons/driver/sundtek-mediatv/package.mk b/packages/addons/driver/sundtek-mediatv/package.mk
index 8edfcb14d6..7418095100 100644
--- a/packages/addons/driver/sundtek-mediatv/package.mk
+++ b/packages/addons/driver/sundtek-mediatv/package.mk
@@ -9,7 +9,7 @@ PKG_ARCH="any"
 PKG_LICENSE="nonfree"
 PKG_SITE="http://support.sundtek.com/"
 PKG_URL=""
-PKG_DEPENDS_TARGET="xmlstarlet:host"
+PKG_DEPENDS_TARGET="xmlstarlet:host p7zip:host"
 PKG_SECTION="driver/dvb"
 PKG_SHORTDESC="Sundtek MediaTV: a Linux driver to add support for SUNDTEK USB DVB devices"
 PKG_LONGDESC="Install this to add support for Sundtek USB DVB devices."
diff --git a/packages/addons/script/script.config.vdr/package.mk b/packages/addons/script/script.config.vdr/package.mk
index 25d807be4c..927e2a8297 100644
--- a/packages/addons/script/script.config.vdr/package.mk
+++ b/packages/addons/script/script.config.vdr/package.mk
@@ -10,7 +10,7 @@ PKG_ARCH="any"
 PKG_LICENSE="OSS"
 PKG_SITE="https://libreelec.tv"
 PKG_URL="https://github.com/LibreELEC/script.config.vdr/archive/$PKG_VERSION.tar.gz"
-PKG_DEPENDS_TARGET="xmlstarlet:host"
+PKG_DEPENDS_TARGET="xmlstarlet:host p7zip:host"
 PKG_SECTION=""
 PKG_SHORTDESC="script.config.vdr"
 PKG_LONGDESC="script.config.vdr"
diff --git a/packages/devel/parallel/package.mk b/packages/devel/parallel/package.mk
deleted file mode 100644
index 83f0cefc69..0000000000
--- a/packages/devel/parallel/package.mk
+++ /dev/null
@@ -1,11 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0
-# Copyright (C) 2019-present Team LibreELEC (https://libreelec.tv)
-
-PKG_NAME="parallel"
-PKG_VERSION="20191022"
-PKG_SHA256="641beea4fb9afccb1969ac0fb43ebc458f375ceb6f7e24970a9aced463e909a9"
-PKG_LICENSE="GPLv3"
-PKG_SITE="https://www.gnu.org/software/parallel/"
-PKG_URL="http://ftpmirror.gnu.org/parallel/$PKG_NAME-$PKG_VERSION.tar.bz2"
-PKG_DEPENDS_HOST=""
-PKG_LONGDESC="GNU parallel is a shell tool for executing jobs in parallel using one or more computers."
diff --git a/packages/linux/package.mk b/packages/linux/package.mk
index cfa3b10d06..196dd57c32 100644
--- a/packages/linux/package.mk
+++ b/packages/linux/package.mk
@@ -6,7 +6,7 @@ PKG_NAME="linux"
 PKG_LICENSE="GPL"
 PKG_SITE="http://www.kernel.org"
 PKG_DEPENDS_HOST="ccache:host rsync:host openssl:host"
-PKG_DEPENDS_TARGET="toolchain linux:host cpio:host kmod:host xz:host wireless-regdb keyutils initramfs:init $KERNEL_EXTRA_DEPENDS_TARGET"
+PKG_DEPENDS_TARGET="toolchain linux:host cpio:host kmod:host xz:host wireless-regdb keyutils $KERNEL_EXTRA_DEPENDS_TARGET"
 PKG_NEED_UNPACK="$LINUX_DEPENDS $(get_pkg_directory initramfs) $(get_pkg_variable initramfs PKG_NEED_UNPACK)"
 PKG_LONGDESC="This package contains a precompiled kernel image and the modules."
 PKG_IS_KERNEL_PKG="yes"
@@ -57,6 +57,13 @@ if [[ "$KERNEL_TARGET" = uImage* ]]; then
   PKG_DEPENDS_TARGET="$PKG_DEPENDS_TARGET u-boot-tools:host"
 fi
 
+# Ensure that the dependencies of initramfs:target are built correctly, but
+# we don't want to add initramfs:target as a direct dependency as we install
+# this "manually" from within linux:target
+for pkg in $(get_pkg_variable initramfs PKG_DEPENDS_TARGET); do
+  ! listcontains "${PKG_DEPENDS_TARGET}" "${pkg}" && PKG_DEPENDS_TARGET+=" ${pkg}" || true
+done
+
 post_patch() {
   cp $PKG_KERNEL_CFG_FILE $PKG_BUILD/.config
 
diff --git a/scripts/build b/scripts/build
index 775daa89df..82419f992d 100755
--- a/scripts/build
+++ b/scripts/build
@@ -63,9 +63,12 @@ case "${TARGET}" in
   "init") _pkg_depends="${PKG_DEPENDS_INIT}";;
   "bootstrap") _pkg_depends="${PKG_DEPENDS_BOOTSTRAP}";;
 esac
-for p in ${_pkg_depends}; do
-  ${SCRIPTS}/build "${p}" "${PARENT_PKG}"
-done
+
+if is_sequential_build; then
+  for p in ${_pkg_depends}; do
+    ${SCRIPTS}/build "${p}" "${PARENT_PKG}"
+  done
+fi
 
 # virtual packages are not built as they only contain dependencies, so dont go further here
 if [ "${PKG_SECTION}" = "virtual" ]; then
@@ -441,8 +444,13 @@ for i in $(find "${SYSROOT_PREFIX}" -type l 2>/dev/null); do
 done
 
 # Transfer the new sysroot content to the shared sysroot
+acquire_update_lock sysroot
+
 mkdir -p "${PKG_ORIG_SYSROOT_PREFIX}"
 cp -PRf "${SYSROOT_PREFIX}"/* "${PKG_ORIG_SYSROOT_PREFIX}"
+
+release_update_lock
+
 rm -rf "${SYSROOT_PREFIX}"
 
 export SYSROOT_PREFIX="${PKG_ORIG_SYSROOT_PREFIX}"
diff --git a/scripts/genbuildplan.py b/scripts/genbuildplan.py
index b1f894e3e2..84adf8925d 100755
--- a/scripts/genbuildplan.py
+++ b/scripts/genbuildplan.py
@@ -109,7 +109,7 @@ class Node:
         self.edges.append(node)
 
 def eprint(*args, **kwargs):
-        print(*args, file=sys.stderr, **kwargs)
+    print(*args, file=sys.stderr, **kwargs)
 
 # Read a JSON list of all possible packages from stdin
 def loadPackages():
@@ -178,7 +178,7 @@ def findbuildpos(node, list):
     return list.index(candidate) + 1 if candidate else -1
 
 # Resolve dependencies for a node
-def dep_resolve(node, resolved, unresolved, noreorder):
+def dep_resolve(node, resolved, unresolved):
     unresolved.append(node)
 
     for edge in node.edges:
@@ -186,19 +186,15 @@ def dep_resolve(node, resolved, unresolved, noreorder):
             if edge in unresolved:
                 raise Exception('Circular reference detected: %s -> %s\nRemove %s from %s package.mk::PKG_DEPENDS_%s' % \
                                 (node.fqname, edge.commonName(), edge.commonName(), node.name, node.target.upper()))
-            dep_resolve(edge, resolved, unresolved, noreorder)
+            dep_resolve(edge, resolved, unresolved)
 
     if node not in resolved:
-        pos = -1 if noreorder else findbuildpos(node, resolved)
-        if pos != -1:
-            resolved.insert(pos, node)
-        else:
-            resolved.append(node)
+        resolved.append(node)
 
     unresolved.remove(node)
 
 # Return a list of build steps for the trigger packages
-def get_build_steps(args, nodes, trigger_pkgs, built_pkgs):
+def get_build_steps(args, nodes):
     resolved = []
     unresolved = []
 
@@ -210,12 +206,12 @@ def get_build_steps(args, nodes, trigger_pkgs, built_pkgs):
     #
     install = True if "image" in args.build else False
 
-    for pkgname in [x for x in trigger_pkgs if x]:
+    for pkgname in [x for x in args.build if x]:
         if pkgname.find(":") == -1:
             pkgname = "%s:target" % pkgname
 
         if pkgname in nodes:
-            dep_resolve(nodes[pkgname], resolved, unresolved, args.no_reorder)
+            dep_resolve(nodes[pkgname], resolved, unresolved)
 
     # Abort if any references remain unresolved
     if unresolved != []:
@@ -226,14 +222,12 @@ def get_build_steps(args, nodes, trigger_pkgs, built_pkgs):
 
     # Output list of resolved dependencies
     for pkg in resolved:
-        if pkg.fqname not in built_pkgs:
-            built_pkgs.append(pkg.fqname)
-            task = "build" if pkg.fqname.endswith(":host") or pkg.fqname.endswith(":init") or not install else "install"
-            yield(task, pkg.fqname)
+        task = "build" if pkg.fqname.endswith(":host") or pkg.fqname.endswith(":init") or not install else "install"
+        yield(task, pkg.fqname)
 
 # Reduce the complete list of packages to a map of those packages that will
 # be needed for the build.
-def processPackages(args, packages, build):
+def processPackages(args, packages):
     # Add dummy package to ensure build/install dependencies are not culled
     pkg = {
             "name": ROOT_PKG,
@@ -241,8 +235,8 @@ def processPackages(args, packages, build):
             "hierarchy": "global",
             "bootstrap": "",
             "init": "",
-            "host": " ".join(get_packages_by_target("host", build)),
-            "target": " ".join(get_packages_by_target("target", build))
+            "host": " ".join(get_packages_by_target("host", args.build)),
+            "target": " ".join(get_packages_by_target("target", args.build))
           }
 
     packages[pkg["name"]] = initPackage(pkg)
@@ -277,16 +271,17 @@ def processPackages(args, packages, build):
             needed_map[pkgname] = pkg
 
     # Validate package dependency references
-    for pkgname in needed_map:
-        pkg = needed_map[pkgname]
-        for t in pkg.deps:
-            for d in pkg.deps[t]:
-                if split_package(d)[0] not in needed_map and not args.ignore_invalid:
-                    msg = 'Invalid package reference: dependency %s in package %s::PKG_DEPENDS_%s is not valid' % (d, pkgname, t.upper())
-                    if args.warn_invalid:
-                        eprint("WARNING: %s" % msg)
-                    else:
-                        raise Exception(msg)
+    if not args.ignore_invalid:
+        for pkgname in needed_map:
+            pkg = needed_map[pkgname]
+            for t in pkg.deps:
+                for d in pkg.deps[t]:
+                    if split_package(d)[0] not in needed_map:
+                        msg = 'Invalid package reference: dependency %s in package %s::PKG_DEPENDS_%s is not valid' % (d, pkgname, t.upper())
+                        if args.warn_invalid:
+                            eprint("WARNING: %s" % msg)
+                        else:
+                            raise Exception(msg)
 
     node_map = {}
 
@@ -336,51 +331,53 @@ parser = argparse.ArgumentParser(description="Generate package dependency list f
 parser.add_argument("-b", "--build", nargs="+", metavar="PACKAGE", required=True, \
                     help="Space-separated list of build trigger packages, either for host or target. Required property - specify at least one package.")
 
-parser.add_argument("--warn-invalid", action="store_true", \
+parser.add_argument("--warn-invalid", action="store_true", default=False, \
                     help="Warn about invalid/missing dependency packages, perhaps excluded by a PKG_ARCH incompatability. Default is to abort.")
 
-parser.add_argument("--no-reorder", action="store_true", default="True", \
-                    help="Do not resequence steps based on dependencies. This is the default.")
-
-parser.add_argument("--reorder", action="store_false", dest="no_reorder", \
-                    help="Disable --no-reorder and resequence packages to try and reduce stalls etc.")
-
-parser.add_argument("--show-wants", action="store_true", \
-                    help="Output \"wants\" dependencies for each step.")
-
-parser.add_argument("--hide-wants", action="store_false", dest="show_wants", default="True", \
-                    help="Disable --show-wants.")
-
-parser.add_argument("--ignore-invalid", action="store_true", \
+parser.add_argument("--ignore-invalid", action="store_true", default=False, \
                     help="Ignore invalid packages.")
 
+group =  parser.add_mutually_exclusive_group()
+group.add_argument("--show-wants", action="store_true", \
+                    help="Output \"wants\" dependencies for each step.")
+group.add_argument("--hide-wants", action="store_false", dest="show_wants", default=True, \
+                    help="Disable --show-wants.  This is the default.")
+
+parser.add_argument("--with-json", metavar="FILE", \
+                    help="File into which JSON formatted plan will be written.")
+
 args = parser.parse_args()
 
 ALL_PACKAGES = loadPackages()
 
 loaded = len(ALL_PACKAGES)
 
-REQUIRED_PKGS = processPackages(args, ALL_PACKAGES, args.build)
+REQUIRED_PKGS = processPackages(args, ALL_PACKAGES)
 
-# Output list of packages to build/install
-built_pkgs = []
-steps = []
-
-for step in get_build_steps(args, REQUIRED_PKGS, args.build, built_pkgs):
-    steps.append(step)
+# Identify list of packages to build/install
+steps = [step for step in get_build_steps(args, REQUIRED_PKGS)]
 
 eprint("Packages loaded : %d" % loaded)
 eprint("Build trigger(s): %d [%s]" % (len(args.build), " ".join(args.build)))
 eprint("Package steps   : %d" % len(steps))
 eprint("")
 
+# Write the JSON build plan (with dependencies)
+if args.with_json:
+    plan = []
+    for step in steps:
+        plan.append({"task": step[0],
+                     "name": step[1],
+                     "deps": [d.fqname for d in REQUIRED_PKGS[step[1]].edges]})
+
+    with open(args.with_json, "w") as out:
+        print(json.dumps(plan, indent=2, sort_keys=False), file=out)
+
 # Output build/install steps
 if args.show_wants:
     for step in steps:
-        wants = []
         node = (REQUIRED_PKGS[step[1]])
-        for e in node.edges:
-            wants.append(e.fqname)
+        wants = [edge.fqname for edge in node.edges]
         print("%-7s %-25s (wants: %s)" % (step[0], step[1].replace(":target",""), ", ".join(wants).replace(":target","")))
 else:
     for step in steps:
diff --git a/scripts/image b/scripts/image
index deb038426e..31c048c8e7 100755
--- a/scripts/image
+++ b/scripts/image
@@ -330,7 +330,7 @@ if [ "${1}" = "release" -o "${1}" = "mkimage" -o "${1}" = "noobs" ]; then
 
         # Re-install u-boot package
         rm ${STAMPS_INSTALL}/u-boot/install_target
-        UBOOT_SYSTEM="${UBOOT_SYSTEM}" ${SCRIPTS}/install u-boot
+        UBOOT_SYSTEM="${UBOOT_SYSTEM}" ${SCRIPTS}/install u-boot 2>&1
 
         # Re-run bootloader/release
         if find_file_path bootloader/release ${BOOTLOADER_DIR}/release; then
diff --git a/scripts/install b/scripts/install
index f4d4ea95e0..c3dbba7368 100755
--- a/scripts/install
+++ b/scripts/install
@@ -45,14 +45,18 @@ mkdir -p ${STAMPS_INSTALL}/${PKG_NAME}
 
 ${SCRIPTS}/build "${1}" "${PARENT_PKG}"
 
-if [ "${TARGET}" = "target" ] ; then
-  for p in ${PKG_DEPENDS_TARGET}; do
-    ${SCRIPTS}/install "${p}" "${PARENT_PKG}"
-  done
-elif [ "${TARGET}" = "init" ] ; then
-  for p in ${PKG_DEPENDS_INIT}; do
-    ${SCRIPTS}/install "${p}" "${PARENT_PKG}"
-  done
+if is_sequential_build || [ "${PARENT_PKG}" = "initramfs:target" ]; then
+  if [ "${TARGET}" = "target" ] ; then
+    for p in ${PKG_DEPENDS_TARGET}; do
+      ${SCRIPTS}/install "${p}" "${PARENT_PKG}"
+    done
+  elif [ "${TARGET}" = "init" ] ; then
+    for p in ${PKG_DEPENDS_INIT}; do
+      ${SCRIPTS}/install "${p}" "${PARENT_PKG}"
+    done
+  fi
+fi
+if [ "${TARGET}" = "init" ] ; then
   INSTALL=${BUILD}/initramfs
 fi
 
@@ -60,6 +64,8 @@ pkg_lock_status "ACTIVE" "${PKG_NAME}:${TARGET}" "install"
 
 build_msg "CLR_INSTALL" "INSTALL" "${PKG_NAME} $(print_color CLR_TARGET "(${TARGET})")" "indent"
 
+acquire_update_lock image
+
 mkdir -p ${INSTALL}
 
 if [ "${TARGET}" = "target" ] ; then
@@ -165,6 +171,8 @@ if [ "${TARGET}" = "target" ] ; then
   pkg_call_exists post_install && pkg_call post_install
 fi
 
+release_update_lock
+
 touch ${STAMP}
 
 pkg_lock_status "UNLOCK" "${PKG_NAME}:${TARGET}" "install" "installed"
diff --git a/scripts/pkgbuild b/scripts/pkgbuild
new file mode 100755
index 0000000000..495a423d83
--- /dev/null
+++ b/scripts/pkgbuild
@@ -0,0 +1,79 @@
+#!/bin/bash
+
+# This function is passed the build instruction for a single job.
+# The function will run either "build <package>" or "install <package>".
+# ${slot} is the job slot number, ie. 1-8 when THREADCOUNT=8.
+# ${job} is the sequence within the total number of ${jobs}.
+package_worker() {
+  local slot=$1 job=$2 jobs=$3 maxslot=$4 task="$5" pkgname="$6" oseqinfo="$7"
+  local result status
+  local addon istarget isaddon
+
+  export MTJOBID=${slot} PARALLEL_SEQ=${job} MTMAXJOBS=${jobs} MTMAXSLOT=${maxslot}
+
+  . config/options "${pkgname}"
+
+  if [ -z "${oseqinfo}" ]; then
+    ${SCRIPTS}/${task} ${pkgname} 2>&1 && result=0 || result=1
+  else
+    print_color CLR_ERROR "FAILURE [${task} ${pkgname}]: a previous dependency process has already failed!"
+    echo
+    echo
+
+    num=0
+    for failed_items in ${oseqinfo//;/ }; do
+      num=$((num + 1))
+      read -r ftask fpkgname fseq <<< "${failed_items//,/ }"
+
+      if [ -n "${fseq}" ]; then
+        [ ${num} -eq 1 ] && echo "The following log(s) for already failed dependencies are available:"
+        printf "  %-7s %s => %s\n" "${ftask}" "${fpkgname}" "${THREAD_CONTROL}/logs/${fseq}.log"
+      else
+        print_color CLR_ERROR "ALREADY FAILED [${ftask} ${fpkg}]"
+        echo
+      fi
+    done
+    echo
+    result=1
+  fi
+
+  [[ ${pkgname} =~ :target$ || "${pkgname//:/}" = "${pkgname}" ]] && istarget="yes" || istarget="no"
+
+  [[ "${MTADDONBUILD}" = "yes" && ( "${PKG_IS_ADDON}" = "yes" || "${PKG_IS_ADDON}" = "embedded" ) ]] && isaddon="yes" || isaddon="no"
+
+  if [ "${isaddon}" = "yes" -a "${istarget}" = "yes" ]; then
+    if [ ${result} -eq 0 ]; then
+      ${SCRIPTS}/install_addon ${pkgname} 2>&1 && result=0 || result=1
+    fi
+
+    if [ ${result} -ne 0 ]; then
+      if [ -d "${THREAD_CONTROL}/logs" ]; then
+        echo "${PKG_NAME} ${THREAD_CONTROL}/logs/${job}.log" >>"${THREAD_CONTROL}/addons.failed"
+      else
+        echo "${PKG_NAME}" >>"${THREAD_CONTROL}/addons.failed"
+      fi
+    fi
+  fi
+
+  (
+    flock --exclusive 95
+    [ ${result} -eq 0 ] && status="DONE" || status="FAIL"
+    num=$(< "${THREAD_CONTROL}/progress")
+    mv "${THREAD_CONTROL}/progress" "${THREAD_CONTROL}/progress.prev"
+    num=$((num + 1))
+    echo ${num} >"${THREAD_CONTROL}/progress"
+  ) 95>"${THREAD_CONTROL}/locks/.progress"
+
+  if [ ${result} -eq 0 ]; then
+    pkg_lock_status "IDLE"
+  else
+    pkg_lock_status "FAILED" "${pkgname}" "${task}"
+
+    print_color CLR_ERROR "FAILURE: $SCRIPTS/${task} ${pkgname} has failed!"
+    echo
+  fi
+
+  return ${result}
+}
+
+package_worker "$1" "$2" "$3" "$4" "$5" "$6" "$7"
diff --git a/scripts/pkgbuilder.py b/scripts/pkgbuilder.py
new file mode 100755
index 0000000000..410bb64a10
--- /dev/null
+++ b/scripts/pkgbuilder.py
@@ -0,0 +1,628 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2019-present Team LibreELEC (https://libreelec.tv)
+
+import sys
+import os
+import datetime, time
+import argparse
+import json
+import codecs
+import copy
+import threading
+import queue
+import subprocess
+import multiprocessing
+
+# Ensure we can output any old crap to stdout and stderr
+sys.stdout = codecs.getwriter("utf-8")(sys.stdout.detach())
+sys.stderr = codecs.getwriter("utf-8")(sys.stderr.detach())
+
+# derive from subprocess to utilize wait4() for rusage stats
+class RusagePopen(subprocess.Popen):
+    def _try_wait(self, wait_flags):
+        try:
+            (pid, sts, ru) = os.wait4(self.pid, wait_flags)
+        except OSError as e:
+            if e.errno != errno.ECHILD:
+                raise
+            pid = self.pid
+            sts = 0
+        else:
+            self.rusage = ru
+        return (pid, sts)
+
+def rusage_run(*popenargs, timeout=None, **kwargs):
+    with RusagePopen(*popenargs, **kwargs) as process:
+        try:
+            stdout, stderr = process.communicate(None, timeout=timeout)
+        except subprocess.TimeoutExpired as exc:
+            process.kill()
+            process.wait()
+            raise
+        except:
+            process.kill()
+            raise
+        retcode = process.poll()
+    res = subprocess.CompletedProcess(process.args, retcode, stdout, stderr)
+    res.rusage = process.rusage
+    return res
+
+class GeneratorEmpty(Exception):
+    pass
+
+class GeneratorStalled(Exception):
+    pass
+
+class Generator:
+    def __init__(self, plan):
+        self.plan = plan
+
+        self.work = copy.deepcopy(self.plan)
+        self.building = {}
+        self.built = {}
+        self.failed = {}
+
+        self.check_no_deps = True
+
+    def canBuildJob(self, job):
+        for dep in job["deps"]:
+            if dep not in self.built:
+                return False
+
+        return True
+
+    def getFirstFailedJob(self, job):
+        for dep in job["deps"]:
+            if dep in self.failed:
+                failedjob = self.getFirstFailedJob(self.failed[dep])
+                if not failedjob:
+                    return self.failed[dep]
+                else:
+                    return failedjob
+
+        return None
+
+    def getAllFailedJobs(self, job):
+        flist = {}
+        for dep in job["deps"]:
+            if dep in self.failed:
+                failedjob = self.getFirstFailedJob(self.failed[dep])
+                if failedjob:
+                    flist[failedjob["name"]] = failedjob
+                else:
+                    flist[dep] = self.failed[dep]
+
+        return [flist[x] for x in flist]
+
+    def getNextJob(self):
+        if self.work == []:
+            raise GeneratorEmpty
+
+        # Always process jobs without dependencies first
+        # until we're sure there's none left...
+        if self.check_no_deps:
+            for i, job in enumerate(self.work):
+                if job["deps"] == []:
+                    self.building[job["name"]] = True
+                    del self.work[i]
+                    job["failedjobs"] = self.getAllFailedJobs(job)
+                    job["logfile"] = None
+                    job["cmdproc"] = None
+                    job["failed"] = False
+                    return job
+
+            self.check_no_deps = False
+
+        # Process remaining jobs, trying to schedule
+        # only those jobs with all their dependencies satisifed
+        for i, job in enumerate(self.work):
+            if self.canBuildJob(job):
+                self.building[job["name"]] = True
+                del self.work[i]
+                job["failedjobs"] = self.getAllFailedJobs(job)
+                job["logfile"] = None
+                job["cmdproc"] = None
+                job["failed"] = False
+                return job
+
+        raise GeneratorStalled
+
+    # Return details about stalled jobs that can't build until the
+    # currently building jobs are complete.
+    def getStallInfo(self):
+        for job in self.work:
+            for dep in job["deps"]:
+                if dep not in self.building and dep not in self.built:
+                    break
+            else:
+                yield (job["name"], [d for d in job["deps"] if d in self.building])
+
+    def activeJobCount(self):
+        return len(self.building)
+
+    def activeJobNames(self):
+        for name in self.building:
+            yield name
+
+    def failedJobCount(self):
+        return len(self.failed)
+
+    def totalJobCount(self):
+        return len(self.plan)
+
+    def completed(self, job):
+        del self.building[job["name"]]
+        self.built[job["name"]] = job
+        if job["failed"]:
+            self.failed[job["name"]] = job
+
+class BuildProcess(threading.Thread):
+    def __init__(self, slot, maxslot, jobtotal, haltonerror, work, complete):
+        threading.Thread.__init__(self, daemon=True)
+
+        self.slot = slot
+        self.maxslot = maxslot
+        self.jobtotal = jobtotal
+        self.haltonerror = haltonerror
+        self.work = work
+        self.complete = complete
+
+        self.active = False
+
+        self.stopping = False
+
+    def stop(self):
+        self.stopping = True
+        self.work.put(None)
+
+    def isActive(self):
+        return self.active == True
+
+    def run(self):
+        while not self.stopping:
+            job = self.work.get(block=True)
+            if job == None or self.stopping:
+                break
+
+            self.active = True
+
+            job["slot"] = self.slot
+            job["failed"] = self.execute(job)
+            job["status"] = "FAIL" if job["failed"] else "DONE"
+            self.complete.put(job)
+
+            self.active = False
+
+            if job["failed"] and self.haltonerror:
+                break
+
+    def execute(self, job):
+        if job["failedjobs"]:
+            flist = []
+            for fjob in job["failedjobs"]:
+                failedinfo = "%s,%s" % (fjob["task"], fjob["name"])
+                if fjob["logfile"]:
+                    failedinfo = "%s,%s" % (failedinfo, fjob["seq"])
+                flist.append(failedinfo)
+            failedinfo = ";".join(flist)
+        else:
+            failedinfo = ""
+
+        job["args"] = ["%s/%s/pkgbuild" % (ROOT, SCRIPTS),
+                       "%d" % self.slot, "%d" % job["seq"], "%d" % self.jobtotal, "%d" % self.maxslot,
+                       job["task"], job["name"], failedinfo]
+
+        job["start"] = time.time()
+        returncode = 1
+        try:
+            if job["logfile"]:
+                with open(job["logfile"], "w") as logfile:
+                    cmd = rusage_run(job["args"], cwd=ROOT,
+                                     stdin=subprocess.PIPE, stdout=logfile, stderr=subprocess.STDOUT,
+                                     universal_newlines=True, shell=False)
+                returncode = cmd.returncode
+                job["cmdproc" ] = cmd
+            else:
+                try:
+                    cmd = rusage_run(job["args"], cwd=ROOT,
+                                     stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.STDOUT,
+                                     universal_newlines=True, shell=False,
+                                     encoding="utf-8", errors="replace")
+                    returncode = cmd.returncode
+                    job["cmdproc" ] = cmd
+                except UnicodeDecodeError:
+                    print('\nPKGBUILDER ERROR: UnicodeDecodeError while reading cmd.stdout from "%s %s"\n' % (job["task"], job["name"]), file=sys.stderr, flush=True)
+        except Exception as e:
+            print("\nPKGBUILDER ERROR: %s exception while executing: %s\n" % (str(e), job["args"]), file=sys.stderr, flush=True)
+
+        job["end"] = time.time()
+        job["elapsed"] = job["end"] - job["start"]
+
+        if job["cmdproc"]:
+            job["utime"] = job["cmdproc"].rusage.ru_utime
+            job["stime"] = job["cmdproc"].rusage.ru_stime
+        else:
+            job["utime"] = job["stime"] = 0
+
+        if job["elapsed"] == 0.0:
+            job["cpu"] = 0.0
+        else:
+            job["cpu"] = round((job["utime"] + job["stime"]) * 100 / job["elapsed"])
+
+        return (returncode != 0)
+
+class Builder:
+    def __init__(self, maxthreadcount, inputfilename, jobglog, loadstats, stats_interval, \
+                 haltonerror=True, log_burst=True, log_combine="always", \
+                 debug=False, verbose=False, colors=False):
+        if inputfilename == "-":
+            plan = json.load(sys.stdin)
+        else:
+            with open(inputfilename, "r") as infile:
+                plan = json.load(infile)
+
+        self.generator = Generator(plan)
+
+        self.joblog = jobglog
+        self.loadstats = loadstats
+        self.stats_interval = int(stats_interval)
+        if self.stats_interval < 1:
+            self.stats_interval = 60
+
+        self.haltonerror = haltonerror
+        self.log_burst = log_burst
+        self.log_combine = log_combine
+        self.debug = debug
+        self.verbose = verbose
+
+        self.colors = (colors == "always" or (colors == "auto" and sys.stderr.isatty()))
+        self.color_code = {}
+        self.color_code["DONE"] = "\033[0;32m" #green
+        self.color_code["FAIL"] = "\033[1;31m" #bold red
+        self.color_code["ACTV"] = "\033[0;33m" #yellow
+        self.color_code["IDLE"] = "\033[0;35m" #magenta
+        self.color_code["INIT"] = "\033[0;36m" #cyan
+
+        self.work = queue.Queue()
+        self.complete = queue.Queue()
+
+        self.jobtotal = self.generator.totalJobCount()
+        self.twidth = len("%d" % self.jobtotal)
+
+        self.joblogfile = None
+        self.loadstatsfile = None
+        self.nextstats = 0
+
+        self.build_start = 0
+
+        # work and completion sequences
+        self.cseq = 0
+        self.wseq = 0
+
+        # parse threadcount
+        if maxthreadcount.endswith("%"):
+            self.threadcount = int(multiprocessing.cpu_count() / 100 * int(args.max_procs.replace("%","")))
+        else:
+            if args.max_procs == "0":
+                self.threadcount = 256
+            else:
+                self.threadcount = int(maxthreadcount)
+
+        self.threadcount = 1 if self.threadcount < 1 else self.threadcount
+        self.threadcount = self.jobtotal if self.jobtotal <= self.threadcount else self.threadcount
+
+        if args.debug:
+            DEBUG("THREADCOUNT#: input arg: %s, computed: %d" % (maxthreadcount, self.threadcount))
+
+        # Init all processes
+        self.processes = []
+        for i in range(1, self.threadcount + 1):
+            self.processes.append(BuildProcess(i, self.threadcount, self.jobtotal, haltonerror, self.work, self.complete))
+
+    def build(self):
+        if self.joblog:
+            self.joblogfile = open(self.joblog, "w")
+
+        if self.loadstats:
+            self.loadstatsfile = open(self.loadstats, "w")
+
+        self.startProcesses()
+
+        self.build_start = time.time()
+
+        # Queue new work until no more work is available, and all queued jobs have completed.
+        while self.queueWork():
+            job = self.getCompletedJob()
+
+            self.writeJobLog(job)
+            self.processJobOutput(job)
+            self.displayJobStatus(job)
+
+            job["cmdproc"] = None
+            job = None
+
+            if self.generator.failedJobCount() != 0 and self.haltonerror:
+                break
+
+        self.captureStats(finished=True)
+        self.stopProcesses()
+
+        if self.joblogfile:
+            self.joblogfile.close()
+
+        if self.loadstatsfile:
+            self.loadstatsfile.close()
+
+        return (self.generator.failedJobCount() == 0)
+
+    # Fill work queue with enough jobs to keep all processes busy.
+    # Return True while jobs remain available to build, or queued jobs are still building.
+    # Return False once all jobs have been queued, and finished building.
+    def queueWork(self):
+        try:
+            for i in range(self.generator.activeJobCount(), self.threadcount):
+                job = self.generator.getNextJob()
+
+                if self.verbose:
+                    self.vprint("INIT", "submit", job["name"])
+
+                if self.debug:
+                    DEBUG("Queueing Job: %s %s" % (job["task"], job["name"]))
+
+                self.wseq += 1
+                job["seq"] = self.wseq
+                if self.log_burst:
+                    job["logfile"] = "%s/logs/%d.log" % (THREAD_CONTROL, job["seq"])
+
+                self.work.put(job)
+
+            if self.verbose:
+                self.vprint("ACTV", "active", ", ".join(self.generator.activeJobNames()))
+
+            if self.debug:
+                freeslots = self.threadcount - self.generator.activeJobCount()
+                DEBUG("Building Now: %d active, %d idle [%s]" % (self.generator.activeJobCount(), freeslots, ", ".join(self.generator.activeJobNames())))
+
+        except GeneratorStalled:
+            if self.verbose:
+                freeslots = self.threadcount - self.generator.activeJobCount()
+                pending = []
+                for (i, (package, wants)) in enumerate(self.generator.getStallInfo()):
+                    pending.append("%s (wants: %s)" % (package, ", ".join(wants)))
+                self.vprint("ACTV", "active", ", ".join(self.generator.activeJobNames()))
+                self.vprint("IDLE", "stalled", "; ".join(pending), p1=len(pending))
+
+            if self.debug:
+                freeslots = self.threadcount - self.generator.activeJobCount()
+                DEBUG("Building Now: %d active, %d idle [%s]" % (self.generator.activeJobCount(), freeslots, ", ".join(self.generator.activeJobNames())))
+                for (i, (package, wants)) in enumerate(self.generator.getStallInfo()):
+                    item = "%-25s wants: %s" % (package, ", ".join(wants))
+                    if i == 0:
+                        DEBUG("Stalled Jobs: %s" % item)
+                    else:
+                        DEBUG("              %s" % item)
+
+        except GeneratorEmpty:
+            if self.generator.activeJobCount() == 0:
+                if self.debug:
+                    DEBUG("NO MORE JOBS: All jobs have completed - exiting.")
+                return False
+            else:
+                if self.debug:
+                    n = self.generator.activeJobCount()
+                    DEBUG("NO MORE JOBS: Waiting on %d job%s to complete..." % (n, ["s",""][n == 1]))
+
+        return True
+
+    # Wait until a new job is available
+    def getCompletedJob(self):
+        while True:
+            try:
+                job = self.complete.get(block=True, timeout=self.captureStats(finished=False))
+                self.generator.completed(job)
+
+                if self.debug:
+                    DEBUG("Finished Job: %s %s [%s] after %0.3f seconds" % (job["task"], job["name"], job["status"], job["elapsed"]))
+
+                return job
+
+            except queue.Empty:
+                pass
+
+    def captureStats(self, finished=False):
+        if not self.loadstatsfile:
+            return None
+
+        now = time.time()
+        if now >= self.nextstats or finished:
+            self.nextstats = int(now - (now % self.stats_interval)) + self.stats_interval
+
+            loadavg = open("/proc/loadavg", "r").readline().split()
+            procs = loadavg[3].split("/")
+            meminfo = dict((i.split()[0].rstrip(':'),int(i.split()[1])) for i in open("/proc/meminfo", "r").readlines())
+
+            print("%d %06d %5s %5s %5s %3s %4s %9d %2d %s" % (now, now - self.build_start, \
+                  loadavg[0], loadavg[1], loadavg[2], procs[0], procs[1], meminfo["MemAvailable"], \
+                  self.generator.activeJobCount(), ",".join(self.generator.activeJobNames())), \
+                  file=self.loadstatsfile, flush=True)
+
+        return (self.nextstats - time.time())
+
+    # Output progress info, and links to any relevant logs
+    def displayJobStatus(self, job):
+        self.cseq += 1
+        print("[%0*d/%0*d] [%s] %-7s %s" %
+              (self.twidth, self.cseq, self.twidth, self.jobtotal,
+               self.colorise(job["status"]), job["task"], job["name"]), file=sys.stderr, flush=True)
+
+        if job["failed"]:
+            if job["logfile"]:
+                print("\nThe following log for this failure is available:\n  %s\n" % job["logfile"], \
+                      file=sys.stderr, flush=True)
+
+            if job["failedjobs"] and job["failedjobs"][0]["logfile"]:
+                if len(job["failedjobs"]) == 1:
+                    print("The following log from the failed dependency may be relevant:", file=sys.stderr)
+                else:
+                    print("The following logs from the failed dependencies may be relevant:", file=sys.stderr)
+                for fjob in job["failedjobs"]:
+                    print("  %-7s %s => %s" % (fjob["task"], fjob["name"], fjob["logfile"]), file=sys.stderr)
+                print("", file=sys.stderr)
+                sys.stderr.flush()
+
+    # If configured, send output for a job (either a logfile, or captured stdout) to stdout
+    def processJobOutput(self, job):
+        log_processed = False
+        log_size = 0
+        log_start = time.time()
+
+        if job["logfile"]:
+            if self.log_combine == "always" or (job["failed"] and self.log_combine == "fail"):
+                try:
+                    with open(job["logfile"], "r", encoding="utf-8", errors="replace") as logfile:
+                        for line in logfile:
+                            print(line, end="")
+                            if self.debug:
+                                log_size += len(line)
+                except UnicodeDecodeError:
+                    print("\nPKGBUILDER ERROR: UnicodeDecodeError while reading log file %s\n" % job["logfile"], file=sys.stderr, flush=True)
+
+                if job["failed"]:
+                    print("\nThe following log for this failure is available:\n  %s\n" % job["logfile"])
+
+                sys.stdout.flush()
+                log_processed = True
+
+        elif job["cmdproc"]:
+            if self.log_combine == "always" or (job["failed"] and self.log_combine == "fail"):
+                for line in job["cmdproc"].stdout:
+                    print(line, end="", file=sys.stdout)
+                    if self.debug:
+                        log_size += len(line)
+                sys.stdout.flush()
+                log_processed = True
+
+        log_elapsed = time.time() - log_start
+
+        if self.debug and log_processed:
+            log_rate = int(log_size / log_elapsed) if log_elapsed != 0 else 0
+            log_data = ", %s" % "/".join(job["logfile"].split("/")[-2:]) if job["logfile"] else ""
+            DEBUG("WRITING LOG : {0:,} bytes in {1:0.3f} seconds ({2:,d} bytes/sec{3:})".format(log_size, log_elapsed, log_rate, log_data))
+
+    # Log completion stats for job
+    def writeJobLog(self, job):
+        if self.joblogfile:
+            print("{j[status]} {j[seq]:0{width}} {j[slot]} {j[task]} {j[name]} " \
+                  "{j[utime]:.{prec}f} {j[stime]:.{prec}f} {j[cpu]} " \
+                  "{j[elapsed]:.{prec}f} {j[start]:.{prec}f} {j[end]:.{prec}f} {0}" \
+                  .format(job["logfile"] if job["logfile"] else "",
+                          j=job, prec=4, width=self.twidth),
+                  file=self.joblogfile, flush=True)
+
+    def startProcesses(self):
+        for process in self.processes:
+            process.start()
+
+    def stopProcesses(self):
+        for process in self.processes:
+            process.stop()
+
+    def vprint(self, status, task, data, p1=None, p2=None):
+       p1 = (self.threadcount - self.generator.activeJobCount()) if p1 == None else p1
+       p2 = self.generator.activeJobCount() if p2 == None else p2
+       print("[%0*d/%0*d] [%4s] %-7s %s" %
+           (self.twidth, p1, self.twidth, p2,
+            self.colorise(status), task, data), file=sys.stderr, flush=True)
+
+    def colorise(self, item):
+        if self.colors:
+            return "%s%-4s\033[0m" % (self.color_code[item], item)
+        return item
+
+def DEBUG(msg):
+    if DEBUG_LOG:
+        print("%s: %s" % (datetime.datetime.now(), msg), file=DEBUG_LOG, flush=True)
+
+parser = argparse.ArgumentParser(description="Run processes to build the specified JSON plan", \
+                                 formatter_class=lambda prog: argparse.HelpFormatter(prog,max_help_position=25,width=90))
+
+parser.add_argument("--max-procs", required=False, default="100%", \
+                    help="Maximum number of processes to use. 0 is unlimited. Can be expressed as " \
+                         "a percentage, for example 50%% (of $(nproc)). Default is 100%%.")
+
+parser.add_argument("--plan", metavar="FILE", default="-", \
+                    help="JSON formatted plan to be processed (default is to read from stdin).")
+
+parser.add_argument("--joblog", metavar="FILE", default=None, \
+                    help="File into which job completion information will be written.")
+
+parser.add_argument("--loadstats", metavar="FILE", default=None, \
+                    help="File into which load average and memory statistics will be written.")
+
+parser.add_argument("--stats-interval", metavar="SECONDS", type=int, default=60, \
+                    help="Sampling interval in seconds for --loadstats. Default is 60.")
+
+group =  parser.add_mutually_exclusive_group()
+group.add_argument("--log-burst", action="store_true", default=True, \
+                    help="Burst job output into individual log files. This is the default.")
+group.add_argument("--no-log-burst", action="store_false", dest="log_burst", \
+                    help="Disable --log-burst, job output is only written to stdout.")
+
+group =  parser.add_mutually_exclusive_group()
+group.add_argument("--log-combine", choices=["always", "never", "fail"], default="always", \
+                    help='Choose when to send job output to stdout. "fail" will send to stdout the ' \
+                         'log of failed jobs only, while "never" will not send any logs to stdout. ' \
+                         'Default is "always".')
+
+group =  parser.add_mutually_exclusive_group()
+group.add_argument("--halt-on-error", action="store_true", default=True, \
+                    help="Halt on first build failure. This is the default.")
+group.add_argument("--continue-on-error", action="store_false", dest="halt_on_error", \
+                    help="Disable --halt-on-error and continue building.")
+
+parser.add_argument("--verbose", action="store_true", default=False, \
+                    help="Output verbose information to stderr.")
+
+parser.add_argument("--debug", action="store_true", default=False, \
+                    help="Enable debug information.")
+
+parser.add_argument("--colors", choices=["always", "never", "auto"], default="auto", \
+                    help="Color code status (DONE, FAIL, etc) labels.")
+
+args = parser.parse_args()
+
+#---------------------------
+
+ROOT = os.environ.get("ROOT", os.path.dirname(os.path.dirname(os.path.realpath(__file__))))
+SCRIPTS = os.environ.get("SCRIPTS", "scripts")
+THREAD_CONTROL = os.environ["THREAD_CONTROL"]
+
+if args.debug:
+    debug_log = "%s/debug.log" % THREAD_CONTROL
+    DEBUG_LOG = open(debug_log, "w")
+    print("Debug information is being written to: %s\n" % debug_log, file=sys.stderr, flush=True)
+else:
+    DEBUG_LOG = None
+
+with open("%s/parallel.pid" % THREAD_CONTROL, "w") as pid:
+    print("%d" % os.getpid(), file=pid)
+
+try:
+    result = Builder(args.max_procs, args.plan, args.joblog, args.loadstats, args.stats_interval, \
+                     haltonerror=args.halt_on_error, \
+                     log_burst=args.log_burst, log_combine=args.log_combine, \
+                     colors=args.colors, debug=args.debug, verbose=args.verbose).build()
+
+    if DEBUG_LOG:
+        DEBUG_LOG.close()
+
+    sys.exit(0 if result else 1)
+except (KeyboardInterrupt, SystemExit) as e:
+    if type(e) == SystemExit:
+        sys.exit(int(str(e)))
+    else:
+        sys.exit(1)
+
diff --git a/scripts/pkgjson b/scripts/pkgjson
new file mode 100755
index 0000000000..789fd51715
--- /dev/null
+++ b/scripts/pkgjson
@@ -0,0 +1,55 @@
+#!/bin/bash
+
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2019-present Team LibreELEC (https://libreelec.tv)
+
+. config/options ""
+
+# This function is passed a list of package.mk paths to be processed.
+# Each package.mk is sourced with relevant variables output in JSON format.
+json_worker() {
+  local packages="$@"
+  local pkgpath hierarchy exited
+
+  exit() { exited=1; }
+
+  for pkgpath in ${packages}; do
+    pkgpath="${pkgpath%%@*}"
+
+    exited=0
+    if ! source_package "${pkgpath}/package.mk" &>/dev/null; then
+      unset -f exit
+      die "$(print_color CLR_ERROR "FAILURE: sourcing package ${pkgpath}/package.mk")"
+    fi
+
+    [ ${exited} -eq 1 ] && continue
+
+    [[ ${pkgpath} =~ ^${ROOT}/${PACKAGES}/ ]] && hierarchy="global" || hierarchy="local"
+
+    cat <<EOF
+  {
+    "name": "${PKG_NAME}",
+    "hierarchy": "${hierarchy}",
+    "section": "${PKG_SECTION}",
+    "bootstrap": "${PKG_DEPENDS_BOOTSTRAP}",
+    "init": "${PKG_DEPENDS_INIT}",
+    "host": "${PKG_DEPENDS_HOST}",
+    "target": "${PKG_DEPENDS_TARGET}"
+  },
+EOF
+  done
+  unset -f exit
+}
+
+if [ "$1" = "--worker" ]; then
+  shift
+  json_worker "$*"
+  exit $?
+fi
+
+# pipefail: return value of a pipeline is the value of the last (rightmost) command to exit with a non-zero status
+set -o pipefail
+
+cat ${_CACHE_PACKAGE_GLOBAL} ${_CACHE_PACKAGE_LOCAL} | \
+  xargs --max-args=64 --max-procs="$(nproc)" "$0" --worker
+exit $?
diff --git a/tools/mtstats.py b/tools/mtstats.py
index a5d809f149..b924ac8aea 100755
--- a/tools/mtstats.py
+++ b/tools/mtstats.py
@@ -49,6 +49,12 @@ class HistoryEvent:
                     return(value)
         return default
 
+def calc_pct(a, b):
+  if b > 0.0:
+      return (a / b) * 100
+  else:
+      return 0.0
+
 def pct_brackets(pct):
     spct = "%04.1f" % pct
     if float(spct) >= 100.0:
@@ -151,7 +157,10 @@ for event in events:
 for slot in slots:
     for status in slots[slot]["statuses"]:
         if status == "IDLE":
-            slots[slot]["statuses"][status]["total"] += (last_active - slots[slot]["statuses"][status]["start"])
+            if slots[slot]["statuses"]["FAILED"]["enabled"] == True:
+                slots[slot]["statuses"][status]["total"] += (last_active - slots[slot]["statuses"]["FAILED"]["start"])
+            else:
+                slots[slot]["statuses"][status]["total"] += (last_active - slots[slot]["statuses"][status]["start"])
         elif slots[slot]["statuses"][status]["enabled"] == True:
             if status != "FAILED":
                 incomplete = True
@@ -161,7 +170,7 @@ for slot in slots:
 
 # Summarise slot data by various criteria
 summary = {}
-cumaltive_total = 0
+cumulative_count = cumulative_total = 0
 for slot in slots:
     acount = atotal = 0
     scount = stotal = 0
@@ -180,7 +189,8 @@ for slot in slots:
     for status in slots[slot]["statuses"]:
         ccount += slots[slot]["statuses"][status]["count"]
         ctotal += slots[slot]["statuses"][status]["total"]
-    cumaltive_total += ctotal
+    cumulative_count += ccount
+    cumulative_total += ctotal
 
     summary[slot] = {"busy":    {"count": acount, "total": atotal},
                      "stalled": {"count": scount, "total": stotal},
@@ -195,12 +205,12 @@ for slot in summary:
 elapsed = (ended - started)
 
 print("Total Build Time: %s (wall clock)" % secs_to_hms(elapsed, blankzero=False))
-print("Accum Build Time: %s (%d slots)\n" % (secs_to_hms(cumaltive_total, blankzero=False), len(slots)))
+print("Accum Build Time: %s (%d slots)\n" % (secs_to_hms(cumulative_total, blankzero=False), len(slots)))
 
 if incomplete:
     print("*** WARNING: active slots detected - build may be in progress/incomplete ***\n")
 
-cum_total = cum_count = cum_pct = 0
+cum_total = 0.0
 print("Breakdown by status (all slots):\n")
 print("  Status   Usage         ( Pct )  Count  State")
 for status in sorted(ALL_STATUSES):
@@ -211,8 +221,8 @@ for status in sorted(ALL_STATUSES):
             count += slots[slot]["statuses"][status]["count"]
             total += slots[slot]["statuses"][status]["total"]
 
-    pct = (100 * total / elapsed / len(slots)) if elapsed > 0.0 else 0.0
-    cum_pct += pct
+    pct = calc_pct(total, cumulative_total)
+    cum_total += total
 
     if status in BUSY_STATUSES:
         stype = "busy"
@@ -221,10 +231,9 @@ for status in sorted(ALL_STATUSES):
     else:
         stype = ""
     print("  %-7s  %12s  %-7s  %-5d  %-5s" % (status, secs_to_hms(total, blankzero=True), pct_brackets(pct),  count, stype))
-    cum_count += count
-    cum_total += total
 print("  -------------------------------------")
-print("  %-7s  %12s  %-7s  %-5d" % ("TOTAL", secs_to_hms(cum_total, blankzero=True), pct_brackets(cum_pct), cum_count))
+print("  %-7s  %12s  %-7s  %-5d" % ("TOTAL", secs_to_hms(cumulative_total, blankzero=True), \
+       pct_brackets(calc_pct(cum_total, cumulative_total)), cumulative_count))
 print("")
 
 print("Peak concurrency: %d out of %d slots\n" % (peak, len(slots)))
@@ -238,30 +247,25 @@ print("#Rank  Slot  Usage        ( Pct )        | # of Slots  Usage        ( Pct
 lines = []
 
 busy_total = 0
-busy_pct = 0
 for rank, slot in enumerate(sorted(summary, key=get_busy_total, reverse=True)):
-    pct = (100 * summary[slot]["busy"]["total"] / elapsed / len(slots)) if elapsed > 0.0 else 0.0
+    pct = calc_pct(summary[slot]["busy"]["total"], cumulative_total)
     state = "active" if slots[slot]["isactive"] == True else " "
     stime = secs_to_hms(summary[slot]["busy"]["total"], blankzero=True)
     busy_total += summary[slot]["busy"]["total"]
-    busy_pct += pct
     lines.append("%s   %s %-7s %6s |" % (slot, stime, pct_brackets(pct), state))
 
 concurrent_total = 0
-concurrent_pct = 0.0
 for rank, concurrentn in enumerate(sorted(concurrency, key=get_concurrent_val, reverse=True)):
     concurrent = concurrency[concurrentn]
-    pct = (100 * concurrent["total"] / elapsed / len(slots)) if elapsed > 0.0 else 0.0
+    pct = calc_pct(concurrent["total"], cumulative_total)
     stime = secs_to_hms(concurrent["total"], blankzero=True)
     concurrent_total += concurrent["total"]
-    concurrent_pct += pct
     lines[rank] += "     %02d      %s %-7s" % (concurrentn, stime, pct_brackets(pct))
 
 for rank, line in enumerate(lines):
     print(" #%02d    %s" % (rank + 1, line))
 
-bpct = spct = "%04.1f" % pct
 print("-----------------------------------------+---------------------------------")
 print(" TOTALS      %s %-7s                      %s %-7s" %
-      (secs_to_hms(busy_total, blankzero=True), pct_brackets(busy_pct),
-       secs_to_hms(concurrent_total, blankzero=True), pct_brackets(concurrent_pct)))
+      (secs_to_hms(busy_total, blankzero=True), pct_brackets(calc_pct(busy_total, cumulative_total)),
+       secs_to_hms(concurrent_total, blankzero=True), pct_brackets(calc_pct(concurrent_total, cumulative_total))))
diff --git a/tools/viewplan b/tools/viewplan
index 09fdc889b6..8a82e97cba 100755
--- a/tools/viewplan
+++ b/tools/viewplan
@@ -6,24 +6,6 @@
 unset _CACHE_PACKAGE_LOCAL _CACHE_PACKAGE_GLOBAL _DEBUG_DEPENDS_LIST _DEBUG_PACKAGE_LIST
 
 . config/options ""
-. config/multithread
 
-# Fake the parallel command if GNU parallel is not available - slow, but works.
-fake_parallel() {
-  while read -r line; do
-    json_worker "${line}"
-  done
-}
-
-PARALLEL_BIN=${TOOLCHAIN}/bin/parallel
-  
-[ -x ${PARALLEL_BIN} ] || PARALLEL_BIN=parallel
-command -v ${PARALLEL_BIN} >/dev/null || PARALLEL_BIN=fake_parallel
-
-# pipefail: return value of a pipeline is the value of the last (rightmost) command to exit with a non-zero status
-set -o pipefail
-
-cat ${_CACHE_PACKAGE_GLOBAL} ${_CACHE_PACKAGE_LOCAL} | \
-  ${PARALLEL_BIN} --plain --no-notice --max-args 30 --halt now,fail=1 json_worker | \
-  ${SCRIPTS}/genbuildplan.py --no-reorder --show-wants --build ${@:-image} --warn-invalid ${GENFLAGS} || \
+${SCRIPTS}/pkgjson | ${SCRIPTS}/genbuildplan.py --show-wants --build ${@:-image} --warn-invalid ${GENFLAGS} || \
     die "FAILURE: Unable to generate plan"