diff --git a/devices/gl-ar750/default.nix b/devices/gl-ar750/default.nix
index a513a78..be683e1 100644
--- a/devices/gl-ar750/default.nix
+++ b/devices/gl-ar750/default.nix
@@ -78,7 +78,7 @@
             part=$(basename $(dirname $(grep -l art /sys/class/mtd/*/name)))
             echo ART partition is ''${part-unset}
             test -n "$part" || exit 1
-            (cd $(mkoutputs ${name}); umask 0027
+            (in_outputs ${name}
              dd if=/dev/$part of=data iflag=skip_bytes,fullblock bs=${toString size} skip=${toString offset} count=1
             )
         '';
diff --git a/pkgs/liminix-tools/networking/pppoe.nix b/pkgs/liminix-tools/networking/pppoe.nix
index e2aaac9..d5c5d69 100644
--- a/pkgs/liminix-tools/networking/pppoe.nix
+++ b/pkgs/liminix-tools/networking/pppoe.nix
@@ -19,7 +19,7 @@ let
   name = "${interface.device}.pppoe";
   ip-up = writeAshScript "ip-up" {} ''
     . ${serviceFns} 
-    (cd $(mkoutputs ${name}); umask 0027
+    (in_outputs ${name}
      echo $1 > ifname
      echo $2 > tty
      echo $3 > speed
diff --git a/pkgs/liminix-tools/networking/udhcpc.nix b/pkgs/liminix-tools/networking/udhcpc.nix
index 8d8d522..b55a489 100644
--- a/pkgs/liminix-tools/networking/udhcpc.nix
+++ b/pkgs/liminix-tools/networking/udhcpc.nix
@@ -16,7 +16,7 @@ let
 
     set_address() {
         ip address replace $ip/$mask dev $interface
-        (cd $(mkoutputs ${name}); umask 0027
+        (in_outputs ${name}
          for i in lease mask ip router siaddr dns serverid subnet opt53 interface ; do
             echo ''${!i} > $i
          done)
diff --git a/pkgs/service-fns/default.nix b/pkgs/service-fns/default.nix
index 2c6dd36..15c5300 100644
--- a/pkgs/service-fns/default.nix
+++ b/pkgs/service-fns/default.nix
@@ -7,4 +7,7 @@ writeText "service-fns.sh" ''
     mkdir -m 2750 -p $d && chown root:system $d
     echo $d
   }
+  in_outputs() {
+    cd `mkoutputs $1` && umask 0027
+  }
 ''
diff --git a/rotuer.nix b/rotuer.nix
index 59f2986..9be278b 100644
--- a/rotuer.nix
+++ b/rotuer.nix
@@ -141,10 +141,8 @@ in rec {
       };
     in bundle {
       name = "bridge-members";
-      contents = map addif [
-        config.hardware.networkInterfaces.wlan_24
-        config.hardware.networkInterfaces.lan
-        config.hardware.networkInterfaces.wlan_5
+      contents = with config.hardware.networkInterfaces; map addif [
+        wlan_24 lan wlan_5
       ];
     };
 
@@ -181,7 +179,7 @@ in rec {
     name = "resolvconf";
     up = ''
       . ${serviceFns}
-      ( cd `mkoutputs ${name}`; umask 0027
+      ( in_outputs ${name}
        echo "nameserver $(output ${services.wan} ns1)" > resolv.conf
        echo "nameserver $(output ${services.wan} ns2)" >> resolv.conf
       )