customStateProvider.js

    .state('redirectArquivo', {
        url: "/download/:codigo",      
                
        resolve : {
            async function($stateParams, $state, $http, $timeout) {
                if ($stateParams.codigo == undefined || $stateParams.codigo == "") {
                    $state.go('404');
                } else {
                    sessionStorage.setItem('codigo', $stateParams.codigo);

                    $timeout(function() {
                        $state.go('downloadArquivo');
                    },0); 
                }
            }
        }      
    })

    .state('downloadArquivo', {
      url: "/download",
      controller: 'PublicController',
      templateUrl: 'views/public/arquivo.view.html'
    })