Jetpack infinite scroll & get template part

Hello there!

I am using the jetpack infinite scroll but i have some problem with get template part…

here is how i have enable the infinite scroll:

add_theme_support( 'infinite-scroll', array(
    'type'           => 'scroll',
    'footer_widgets' => false,
    'container'      => 'main',
    'footer'         => false,
    'wrapper'        => false,
    'render'         => false,
    'posts_per_page' => false,
) );

and here is the loop:

<div id="main">
<?php if (have_posts()) : ?>
	<?php while (have_posts()) : the_post(); ?>
		<?php get_template_part( 'content', 'custom' ); ?>
	<?php endwhile; ?>
<?php endif; ?>
</div>

now, the infinite scroll works fine BUT the first 7 posts are from content-custom.php and all the other posts that are loading are from content.php…

I want to load posts only from content-custom.php when i scroll down… How can this be done?

Thank you?