diff --git a/plist b/plist
index 3dbebcc63..336598a5c 100644
--- a/plist
+++ b/plist
@@ -134,6 +134,7 @@
 /usr/local/etc/rc.subr.d/livemode
 /usr/local/etc/rc.subr.d/recover
 /usr/local/etc/rc.subr.d/swapon
+/usr/local/etc/rc.subr.d/tmp
 /usr/local/etc/rc.subr.d/var
 /usr/local/etc/rc.syshook
 /usr/local/etc/rc.syshook.d/05-beep.stop
diff --git a/src/etc/rc b/src/etc/rc
index 215428d04..554402a7a 100755
--- a/src/etc/rc
+++ b/src/etc/rc
@@ -134,14 +134,8 @@ fi
 # write /var/run/dmesg.boot
 /etc/rc.d/dmesg onestart
 
-USE_MFS_TMP=$(/usr/bin/grep -c 'use_mfs_tmp[^_]' /conf/config.xml)
-
-if [ ${USE_MFS_TMP} -ne 0 ]; then
-	mount -t tmpfs -o mode=01777 tmpfs /tmp
-else
-	rm -rf /tmp/*
-	chmod 1777 /tmp
-fi
+# all sorts of maintenance tasks for /tmp
+/usr/local/etc/rc.subr.d/tmp
 
 # set up and recover a crash dump before activating swap
 /usr/local/etc/rc.subr.d/crashdump
diff --git a/src/etc/rc.subr.d/tmp b/src/etc/rc.subr.d/tmp
new file mode 100755
index 000000000..19a975238
--- /dev/null
+++ b/src/etc/rc.subr.d/tmp
@@ -0,0 +1,46 @@
+#!/bin/sh
+
+# Copyright (c) 2014-2018 Franco Fichtner <franco@opnsense.org>
+# Copyright (c) 2004-2010 Scott Ullrich <sullrich@gmail.com>
+# Copyright (c) 2003-2004 Manuel Kasper <mk@neon1.net>
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+#
+# 2. 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.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+
+USE_MFS_TMP=$(/usr/bin/grep -c 'use_mfs_tmp[^_]' /conf/config.xml)
+
+# see if / is writable (aka. non-LiveCD boot)
+if _tmpdir=$(mktemp -d -q /.diskless.XXXXXX); then
+	# only remove the directory
+	rmdir ${_tmpdir}
+else
+	USE_MFS_TMP=0
+fi
+
+if [ ${USE_MFS_TMP} -ne 0 ]; then
+	mount -t tmpfs -o mode=01777 tmpfs /tmp
+else
+	rm -rf /tmp/*
+	chmod 1777 /tmp
+fi