diff --git a/bin/fk b/bin/fk
index 85548e3..9e2ee67 100755
--- a/bin/fk
+++ b/bin/fk
@@ -1,13 +1,17 @@
 #!/bin/sh -e
-if [ "${1#usb}" = "$1" ]; then
-    if ! ping -c 1 -w 1 "$1" >/dev/null; then
-	echo "no ping response from $1" 1>&2
-	exit 1
-    fi
-    NN=$1
+if [ "$1" = -u ]; then
+    NN=
 else
-    NN=`ifconfig ${1:-usb0} |
-      sed '/.*inet addr:\([^ ]*\).*/{s//\1/;s/100$/101/;s/200$/202/;p;};d'`
+    if [ "${1#usb}" = "$1" ]; then
+	if ! ping -c 1 -w 1 "$1" >/dev/null; then
+	    echo "no ping response from $1" 1>&2
+	    exit 1
+	fi
+	NN=$1
+    else
+	NN=`ifconfig ${1:-usb0} |
+	  sed '/.*inet addr:\([^ ]*\).*/{s//\1/;s/100$/101/;s/200$/202/;p;};d'`
+    fi
 fi
 if [ "$NN" ]; then
     echo "SCP to $NN" 1>&2