Update user via REST (and under AngularsJS) I need to update a user fields via REST SERVICE. I'm under AngularJS, so this is my function into my .service()

setMyUtx: function (params) {
            return $http({
                method : 'PUT',
                url : 'http://XXXXXXXX/rest/user/'+params.uid,
                data : {'data' : params.value},
                headers : { 'X-CSRF-Token' : $cookies['csrftoken'],'Content-Type': 'application/json;charset=utf-8'},
                cache : false
            })
        },


where params.value is : 

var data = {};
      data.field_primary_aircraft = {};
      data.field_primary_aircraft.und = [{value:1}];
      ProfileService.setMyUtx({'uid' : $scope.datiUtente.uid, 'value' : data});


If I exec this function, my drupal site return no error with this output: 

{"field_primary_aircraft":{"und":[{"value":0}]},"uid":"7","roles":{"2":"authenticated user"}}


But no update is done (I know it because the original value of field_primary_aircraft is 1). 

Why this ? Where is my error ?
I suggest you first try to test it with a browser REST application extension.
I would recommend this for Firefox: https://addons.mozilla.org/he/firefox/addon/rest-easy/

If you still doesn't get any error, check your watchdog... there is no reason this shouldn't work.