diff --git a/mbed_app.json b/mbed_app.json
index 5c33375..adc3b58 100644
--- a/mbed_app.json
+++ b/mbed_app.json
@@ -1,6 +1,6 @@
 {
     "config": {
-        "tx-timer":            { "value": 30000 },
+        "tx-timer":            { "value": 600000 },
         "lora-radio": {
             "help": "Which radio to use (options: SX1272,SX1276)",
             "value": "SX1276"
@@ -61,8 +61,6 @@
             "main_stack_size":      1024,
             "target.lpticker_lptim": 0,
             "target.clock_source": "USE_PLL_HSI",
-            "lora.duty-cycle-on":  false,
-            "tx-timer":            600000,
             "lora-radio":          "SX1272",
             "lora-spi-mosi":       "D11",
             "lora-spi-miso":       "D12",
diff --git a/scripts/gen_images.sh b/scripts/gen_images.sh
index 7359cdc..d510446 100755
--- a/scripts/gen_images.sh
+++ b/scripts/gen_images.sh
@@ -13,9 +13,18 @@ if [ $# -ne 2 ]; then
   exit 1;
 fi
 
+SED=sed
 MASTER=$1
 DEVICES=$2
 
+if [[ $OSTYPE == "darwin"* ]]; then
+  if ! command -v gsed > /dev/null 2>&1; then
+    echo "You need gnu-sed on darwin system (available with homebrew)"
+    exit 1
+  fi
+  SED=gsed
+fi
+
 if [ ! -e $MASTER ]; then
   echo "The master file $MASTER doesn't exists"
   exit 1;
@@ -31,8 +40,8 @@ for DEVICE in $(cat $DEVICES); do
   deviceeui=$(echo $DEVICE | cut -d : -f 2)
   appeui=$(echo $DEVICE | cut -d : -f 3)
   appkey=$(echo $DEVICE | cut -d : -f 4)
-  echo $name
-  hexdump -ve '1/1 "%.2X"' $MASTERFILE | sed "s/$DEVICEEUI/$deviceeui/; s/$APPEUI/$appeui/; s/$APPKEY/$appkey/" | xxd -r -p > waveofhoney-${name}.bin
+  echo "Generating device $name ($deviceeui)"
+  hexdump -ve '1/1 "%.2X"' $MASTER | $SED "s/${DEVICEEUI}/${deviceeui}/; s/${APPEUI}/${appeui}/; s/${APPKEY}/${appkey}/" | xxd -r -p - ${deviceeui}.bin
 done
 
 exit;
\ No newline at end of file