$rootScope.$on('$viewHistory.historyChange', function(e, data) {
        $scope.isBackButtonShown = !!data.showBack;
    });

.config(function($stateProvider, $urlRouterProvider, $ionicConfigProvider) {

  $ionicConfigProvider.backButton.previousTitleText(false).text('customText');
  $ionicConfigProvider.backButton.icon('ion-ios-home');
})

.controller('yourCtrl', function($scope) {

$scope.$on('$ionicView.beforeEnter', function (event, viewData) {
  viewData.enableBack = true;
});

})