How to use WordPress multisite with mixed HTTP and HTTPS sites?

Thanks to @Sorin for posting the trac. From there I found a solution using just filters in functions.php (so no editing the core)

Thanks @mensmaximus for posting there:

Link: https://core.trac.wordpress.org/ticket/33887#comment:3

<?php
add_filter( 'network_admin_url', 'mmx_network_admin_url', 1, 2 );
function mmx_network_admin_url( $url, $path ){
    $url = "https://my_master_domain/wp-admin/network/" . $path;
    return $url;
}

add_filter( 'admin_url', 'mmx_admin_url', 1, 3 );
function mmx_admin_url( $url, $path, $blog_id ) {
    $blog_id = ( $blog_id ) ? $blog_id : get_current_blog_id();
    if ( preg_match( '|^http(s)?://|', $url) ) {
        $blog_details = get_blog_details( $blog_id );
        $url = $blog_details->siteurl . '/wp-admin/' . $path;
    }
    return $url;
}