I'm using the same form both creating and editing model, however, it cannot be edited if the file is not selected since ngf-select requires it

form.html

<form class="form-horizontal" role="form" class="edit-user">
  <div class="form-group">
    <label for="name" class="col-md-2 control-label col-md-offset-2">
      Pavadinimas
    </label>
    <div class="col-md-5">
      <input type="text" name="name" class="form-control" placeholder="{{program.title}}" ng-model="program.title" value="{{program.title}}">
    </div>
    <label for="id" class="col-md-2 control-label col-md-offset-2">
      ID
    </label>
    <div class="col-md-5">
      <input type="text" name="name" class="form-control" placeholder="{{program.title}}" ng-model="program.id">
    </div>
     <div>
   <h4>Upload on file select</h4>
  <button type="file" ngf-select ng-model="file"
          accept="image/*" ngf-max-height="1000" ngf-max-size="1MB">
      Select File</button>
  <br><br>
  File:
  <div style="font:smaller">{{f.name}} {{errFile.name}} {{errFile.$error}} {{errFile.$errorParam}}
      <span class="progress" ng-show="f.progress >= 0">
          <div style="width:{{f.progress}}%"  
               ng-bind="f.progress + '%'"></div>
      </span>
  </div>     
  {{errorMsg}}
      </div>
    </div>
  </div>
  <div class="form-group" >
    <label
      for="description"
      class="col-md-2 control-label col-md-offset-2">
      Aprašymas
    </label>
    <div class="col-md-5">
      <textarea name="description" class="form-control" ng-model='program.description' placeholder="e.g. Flambé for 20 seconds">
      </textarea>
    </div>
  </div>
  <div class="form-group">
    <div class="col-md-offset-2 col-md-3">
      <button class="btn btn-default" ng-click="cancel()"> Atšaukti</button>
    </div>
    <div class="col-md-4 text-right">
      <button class="btn btn-success" 
              ng-click="uploadFiles(file)">Submit</button>
    </div>
  </div>
</section>

programController.js

        $scope.uploadFiles = function(file, errFiles) {
        if ($scope.program.id) {
        $scope.f = file;
        $scope.errFile = errFiles && errFiles[0];
        if (file) {
            file.upload = Upload.upload({
            url: '/programs/3.json',
            method: 'PUT',
            fields:  {'program[title]': $scope.program.title, 'program[avatar]': $scope.program.file, 'program[description]': $scope.program.description, 'program[id]': $scope.program.id}
        });
            file.upload.then(function (response) {
                $timeout(function () {
                    file.result = response.data;
                });
            }, function (response) {
                if (response.status > 0)
                    $scope.errorMsg = response.status + ': ' + response.data;
            }, function (evt) {
                file.progress = Math.min(100, parseInt(100.0 * 
                                         evt.loaded / evt.total));
            });
        }  } return $location.path("/dashboard/programos/");
    };