diff --git a/app/scripts/controllers/register.js b/app/scripts/controllers/register.js
index 95ff8440..d4cba766 100644
--- a/app/scripts/controllers/register.js
+++ b/app/scripts/controllers/register.js
@@ -67,6 +67,7 @@
     };
     vm.privacy = false;
     vm.completed = false;
+    vm.sensorIncomplete = true;
 
     //new sensebox object
     vm.newSenseBox = {
@@ -128,9 +129,7 @@
     vm.markers = {};
     vm.sensors = [];
     vm.editMarkerInput = {};
-    vm.sensorSetup = '';
     vm.editing = {};
-    vm.isCustom = {};
     vm.events = {
       autolocation: true,
     };
@@ -182,7 +181,7 @@
     function randomFixedInteger (length) {
       return Math.floor(
         Math.pow(10, length - 1) +
-          Math.random() * (Math.pow(10, length) - Math.pow(10, length - 1) - 1)
+        Math.random() * (Math.pow(10, length) - Math.pow(10, length - 1) - 1)
       );
     }
 
@@ -208,7 +207,7 @@
         .then(function (response) {
           vm.boxScript = response;
         })
-        .catch(function () {});
+        .catch(function () { });
     }
 
     function compile () {
@@ -218,8 +217,8 @@
         board: 'sensebox-mcu',
         sketch: vm.boxScript,
       })
-        .then(function () {})
-        .catch(function () {})
+        .then(function () { })
+        .catch(function () { })
         .finally(function () {
           vm.compiling = false;
         });
@@ -326,15 +325,14 @@
 
     function add (icon, title, unit, sensorType) {
       var sensor = {
-        id: vm.sensors.length,
+        id: randomFixedInteger(4),
+        index: vm.sensors.length,
         icon: icon,
         title: title,
         unit: unit,
         sensorType: sensorType,
       };
       vm.sensors.push(sensor);
-      vm.sensorSetup = JSON.stringify(vm.sensors);
-      edit(sensor.id);
       vm.sensorIncomplete = false;
 
       if (vm.ttn.profile === 'cayenne-lpp') {
@@ -344,16 +342,11 @@
 
     function remove (index) {
       vm.sensors.splice(index, 1);
-      vm.isCustom[index] = false;
-      vm.editing[index] = false;
       for (var i = 0; i < vm.sensors.length; i++) {
-        vm.sensors[i].id = i;
+        vm.sensors[i].index = i;
       }
       if (vm.sensors.length === 0) {
-        vm.sensorSetup = '';
         vm.sensorIncomplete = true;
-      } else {
-        vm.sensorSetup = JSON.stringify($scope.sensors);
       }
 
       if (vm.ttn.profile === 'cayenne-lpp') {
@@ -361,10 +354,6 @@
       }
     }
 
-    function edit (index) {
-      vm.editing[index] = true;
-    }
-
     function setSensorIcon (sensor, newIcon) {
       sensor.icon = newIcon.name;
     }
@@ -381,7 +370,7 @@
         .then(function (data) {
           vm.boxScript = data;
         })
-        .catch(function () {});
+        .catch(function () { });
     }
 
     function completeRegistration () {
@@ -515,6 +504,7 @@
     function senseBoxSetupValid () {
       var validTTN = true;
       var validMQTT = true;
+      var validSensorSetup = false;
 
       if (vm.ttnEnabled) {
         validTTN = vm.validTTNconfig;
@@ -524,7 +514,11 @@
         validMQTT = vm.validMQTTURL;
       }
 
-      return validTTN && validMQTT;
+      if (vm.modelSelected.id === 'custom' || vm.modelSelected.id === 'edu') {
+        validSensorSetup = vm.sensorIncomplete;
+      }
+
+      return validTTN && validMQTT && !validSensorSetup;
     }
 
     function generateSensorTemplate (templateName) {
@@ -804,7 +798,7 @@
                 map.setView([vm.markers.box.lat, vm.markers.box.lng], 16);
               }
             })
-            .catch(function () {});
+            .catch(function () { });
         }, 200);
       }
     });
@@ -812,7 +806,6 @@
     $scope.$watch('register.modelSelected.id', function (newValue) {
       if (newValue.indexOf('home') === 0) {
         vm.modelSelected.name = 'senseBox Home ' + newValue.substring(4);
-        vm.sensorSetup = vm.modelSelected.id;
 
         vm.newModel.connection = null;
         vm.extensions.feinstaub.id = '';
@@ -823,7 +816,6 @@
       }
 
       if (newValue.indexOf('luftdaten') === 0) {
-        vm.sensorSetup = vm.modelSelected.id;
         vm.extensions.feinstaub.id = '';
         vm.newModel.connection = null;
 
@@ -845,13 +837,11 @@
       }
 
       if (newValue.indexOf('hackair') === 0) {
-        vm.sensorSetup = vm.modelSelected.id;
         vm.extensions.feinstaub.id = '';
         vm.newModel.connection = null;
       }
 
       if (newValue === 'custom') {
-        vm.sensorSetup = '';
         vm.extensions.feinstaub.id = '';
         vm.newModel.connection = null;
         vm.newModel.sensors = {
diff --git a/app/views/account.box.register.html b/app/views/account.box.register.html
index 4d60cf10..f6dec056 100644
--- a/app/views/account.box.register.html
+++ b/app/views/account.box.register.html
@@ -899,8 +899,7 @@ <h4>CO<sub>2</sub></h4>
                           <input type="text" name="icon{{sensor.id}}" ng-hide="true" ng-model="sensor.icon" required>
                           <div class="form-group has-feedback"
                             ng-class="{ 'has-error' : senseboxForm.icon{{sensor.id}}.$invalid, 'has-success' : senseboxForm.icon{{sensor.id}}.$valid && sensor.icon!='' }">
-                            <div class="btn-group xxxl" uib-dropdown
-                              ng-show="register.editing[sensor.id] && !register.isCustom[sensor.id]">
+                            <div class="btn-group xxxl" uib-dropdown>
                               <button id="btn-append-to-body" type="button" class="form-control btn btn-default xxxl"
                                 uib-dropdown-toggle>
                                 <span class="icon osem-icon" ng-class="sensor.icon"></span><span
@@ -921,7 +920,8 @@ <h4>CO<sub>2</sub></h4>
                         </td>
                         <td>
                           <div class="form-group has-feedback"
-                            ng-class="{ 'has-error' : senseboxForm.phenomenom{{sensor.id}}.$invalid, 'has-success' : senseboxForm.phenomenom{{sensor.id}}.$invalid && sensor.title!='' }">
+                            ng-class="{ 'has-error' : senseboxForm.phenomenom{{sensor.id}}.$invalid, 'has-success' : senseboxForm.phenomenom{{sensor.id}}.$valid && sensor.title!='' }">
+                            <!-- ng-class="{ 'has-error' : senseboxForm.phenomenom{{sensor.id}}.$invalid, 'has-success' : senseboxForm.phenomenom{{sensor.id}}.$invalid && sensor.title!='' }"> -->
                             <input name="phenomenom{{sensor.id}}" class="form-control" type="text"
                               ng-model="sensor.title" required>
                             <span ng-show="senseboxForm.phenomenom{{sensor.id}}.$valid && sensor.title!=''"
@@ -953,8 +953,9 @@ <h4>CO<sub>2</sub></h4>
                           </div>
                         </td>
                         <td style="white-space: nowrap">
-                          <button type="button" class="btn btn-danger" ng-show="register.editing[sensor.id]"
-                            ng-click="register.remove(sensor.id);">
+                          <button type="button" class="btn btn-danger" ng-click="register.remove(sensor.index);">
+                          <!-- <button type="button" class="btn btn-danger" ng-show="register.editing[sensor.id]"
+                            ng-click="register.remove(sensor.id);"> -->
                             <span class="glyphicon glyphicon-trash"></span>
                           </button>
                         </td>
@@ -1122,8 +1123,7 @@ <h4>CO<sub>2</sub></h4>
                           <input type="text" name="icon{{sensor.id}}" ng-hide="true" ng-model="sensor.icon" required>
                           <div class="form-group has-feedback"
                             ng-class="{ 'has-error' : senseboxForm.icon{{sensor.id}}.$invalid, 'has-success' : senseboxForm.icon{{sensor.id}}.$valid && sensor.icon!='' }">
-                            <div class="btn-group xxxl" uib-dropdown
-                              ng-show="register.editing[sensor.id] && !register.isCustom[sensor.id]">
+                            <div class="btn-group xxxl" uib-dropdown>
                               <button id="btn-append-to-body" type="button" class="form-control btn btn-default xxxl"
                                 uib-dropdown-toggle>
                                 <span class="icon osem-icon" ng-class="sensor.icon"></span><span
@@ -1176,8 +1176,9 @@ <h4>CO<sub>2</sub></h4>
                           </div>
                         </td>
                         <td style="white-space: nowrap">
-                          <button type="button" class="btn btn-danger" ng-show="register.editing[sensor.id]"
-                            ng-click="register.remove(sensor.id);">
+                          <button type="button" class="btn btn-danger" ng-click="register.remove(sensor.index);">
+                          <!-- <button type="button" class="btn btn-danger" ng-show="register.editing[sensor.id]"
+                            ng-click="register.remove(sensor.id);"> -->
                             <span class="glyphicon glyphicon-trash"></span>
                           </button>
                         </td>
@@ -1319,6 +1320,11 @@ <h1><small>{{ 'STEP2_SUB4' | translate }}</small></h1>
                     <label class="control-label">{{ 'TTN_DECODEOPTIONS' | translate }}</label>
                     <input type="text" name="ttn_decodeoptions" class="form-control monospace"
                       ng-model="register.ttn.decodeOptions" ng-disabled="register.ttn.profile === 'sensebox/home'"
+                      ng-required="register.ttn.profile !== 'sensebox/home'">
+                  </div>
+                  <!-- TTN Port -->
+                  <div class="form-group">
+                    <label class="control-label">{{ 'TTN_PORT' | translate }}</label>
                       ng-required="register.ttn.profile !== 'sensebox/home'"
                       ng-show="register.ttn.profile != 'cayenne-lpp'">
                     <table class="table table-striped table-bordered" ng-show="register.ttn.profile == 'cayenne-lpp'">