How to switch to different Storyboard for iPhone 5?

I was looking for the same answer couple of weeks ago here’s my solution hope helps..

-(void)initializeStoryBoardBasedOnScreenSize {

    if ([UIDevice currentDevice].userInterfaceIdiom == UIUserInterfaceIdiomPhone)
{    // The iOS device = iPhone or iPod Touch


    CGSize iOSDeviceScreenSize = [[UIScreen mainScreen] bounds].size;

    if (iOSDeviceScreenSize.height == 480)
    {   // iPhone 3GS, 4, and 4S and iPod Touch 3rd and 4th generation: 3.5 inch screen (diagonally measured)

        // Instantiate a new storyboard object using the storyboard file named Storyboard_iPhone35
        UIStoryboard *iPhone35Storyboard = [UIStoryboard storyboardWithName:@"Storyboard_iPhone35" bundle:nil];

        // Instantiate the initial view controller object from the storyboard
        UIViewController *initialViewController = [iPhone35Storyboard instantiateInitialViewController];

        // Instantiate a UIWindow object and initialize it with the screen size of the iOS device
        self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];

        // Set the initial view controller to be the root view controller of the window object
        self.window.rootViewController  = initialViewController;

        // Set the window object to be the key window and show it
        [self.window makeKeyAndVisible];
    }

    if (iOSDeviceScreenSize.height == 568)
    {   // iPhone 5 and iPod Touch 5th generation: 4 inch screen (diagonally measured)

        // Instantiate a new storyboard object using the storyboard file named Storyboard_iPhone4
        UIStoryboard *iPhone4Storyboard = [UIStoryboard storyboardWithName:@"Storyboard_iPhone4" bundle:nil];

        // Instantiate the initial view controller object from the storyboard
        UIViewController *initialViewController = [iPhone4Storyboard instantiateInitialViewController];

        // Instantiate a UIWindow object and initialize it with the screen size of the iOS device
        self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];

        // Set the initial view controller to be the root view controller of the window object
        self.window.rootViewController  = initialViewController;

        // Set the window object to be the key window and show it
        [self.window makeKeyAndVisible];
    }

    } else if ([UIDevice currentDevice].userInterfaceIdiom == UIUserInterfaceIdiomPad)

    {   // The iOS device = iPad

    UISplitViewController *splitViewController = (UISplitViewController *)self.window.rootViewController;
    UINavigationController *navigationController = [splitViewController.viewControllers lastObject];
    splitViewController.delegate = (id)navigationController.topViewController;

    }
}

Call this method under AppDelegate ddiFinishLaunchingWithOptions: method
And also don’t forget the name your storyboards properly

Hope helps…