diff --git a/package/base-files/files/lib/functions/preinit.sh b/package/base-files/files/lib/functions/preinit.sh
new file mode 100644
index 0000000..591e810
--- /dev/null
+++ b/package/base-files/files/lib/functions/preinit.sh
@@ -0,0 +1,87 @@
+# Copyright (C) 2006-2013 OpenWrt.org
+# Copyright (C) 2010 Vertical Communications
+
+boot_hook_splice_start() {
+	export -n PI_HOOK_SPLICE=1
+}
+
+boot_hook_splice_finish() {
+	local hook
+	for hook in $PI_STACK_LIST; do
+		local v; eval "v=\${${hook}_splice:+\$${hook}_splice }$hook"
+		export -n "${hook}=${v% }"
+		export -n "${hook}_splice="
+	done
+	export -n PI_HOOK_SPLICE=
+}
+
+boot_hook_init() {
+	local hook="${1}_hook"
+	export -n "PI_STACK_LIST=${PI_STACK_LIST:+$PI_STACK_LIST }$hook"
+	export -n "$hook="
+}
+
+boot_hook_add() {
+	local hook="${1}_hook${PI_HOOK_SPLICE:+_splice}"
+	local func="${2}"
+
+	[ -n "$func" ] && {
+		local v; eval "v=\$$hook"
+		export -n "$hook=${v:+$v }$func"
+	}
+}
+
+boot_hook_shift() {
+	local hook="${1}_hook"
+	local rvar="${2}"
+
+	local v; eval "v=\$$hook"
+	[ -n "$v" ] && {
+		local first="${v%% *}"
+
+		[ "$v" != "${v#* }" ] && \
+			export -n "$hook=${v#* }" || \
+			export -n "$hook="
+
+		export -n "$rvar=$first"
+		return 0
+	}
+
+	return 1
+}
+
+boot_run_hook() {
+	local hook="$1"
+	local func
+
+	while boot_hook_shift "$hook" func; do
+		local ran; eval "ran=\$PI_RAN_$func"
+		[ -n "$ran" ] || {
+			export -n "PI_RAN_$func=1"
+			$func "$1" "$2"
+		}
+	done
+}
+
+pivot() { # <new_root> <old_root>
+	/bin/mount -o noatime,move /proc $1/proc && \
+	pivot_root $1 $1$2 && {
+		/bin/mount -o noatime,move $2/dev /dev
+		/bin/mount -o noatime,move $2/tmp /tmp
+		/bin/mount -o noatime,move $2/sys /sys 2>&-
+		/bin/mount -o noatime,move $2/overlay /overlay 2>&-
+		return 0
+	}
+}
+
+fopivot() { # <rw_root> <work_dir> <ro_root> <dupe?>
+	/bin/mount -o noatime,lowerdir=/,upperdir=$1,workdir=$2 -t overlay "overlayfs:$1" /mnt
+	pivot /mnt $3
+}
+
+ramoverlay() {
+	mkdir -p /tmp/root
+	/bin/mount -t tmpfs -o noatime,mode=0755 root /tmp/root
+	mkdir -p /tmp/root/root /tmp/root/work
+	fopivot /tmp/root/root /tmp/root/work /rom 1
+}