diff --git a/modules/system/boot/stage-2-init.sh b/modules/system/boot/stage-2-init.sh
index f02149ced75..cc0f8befae8 100644
--- a/modules/system/boot/stage-2-init.sh
+++ b/modules/system/boot/stage-2-init.sh
@@ -102,16 +102,18 @@ mkdir -m 0755 -p /etc/nixos
 rm -rf /var/run /var/lock /var/log/upstart
 rm -f /etc/resolv.conf
 
-#echo -n "cleaning \`/tmp'..."
-#rm -rf --one-file-system /tmp/*
-#echo " done"
+if test -n "@cleanTmpDir@"; then
+    echo -n "cleaning \`/tmp'..."
+    find /tmp -maxdepth 1 -mindepth 1 -print0 | xargs -0r rm -rf --one-file-system
+    echo " done"
+else
+    # Get rid of ICE locks...
+    rm -rf /tmp/.ICE-unix
+fi
 
-
-# Get rid of ICE locks and ensure that it's owned by root.
-rm -rf /tmp/.ICE-unix
+# ... and ensure that it's owned by root.
 mkdir -m 1777 /tmp/.ICE-unix
 
-
 # This is a good time to clean up /nix/var/nix/chroots.  Doing an `rm
 # -rf' on it isn't safe in general because it can contain bind mounts
 # to /nix/store and other places.  But after rebooting these are all