Damn button.

gistfile1.txt

- (void)viewDidLoad {
    [super viewDidLoad];

    UIBarButtonItem *item = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemSave target:self action:@selector(onSave)];
    item.enabled = NO;
    NSLog(@"%@", item);  // OBJ is NOT nil here.
    self.navigationItem.rightBarButtonItem = item;
}

// the button appears enabled.