Show navigation menu main site in submenu of subsites

Hi, i’m trying to show menu navigation of main site at submenu in sites of the network. I’m using network wide menu, but i don’t know how to select the menu location. All sites use the same theme

In main site i have:
—- menu1: about us
—- menu2: navigation

And i want to see menu2 at menu1 place in network sites.
i know is little code, but i’m trying and trying and nothing, i can only select the menu i want to show changing last number at line35:
$current = array_slice( $registered, absint( $slot – 1 ), 1 );

But i can’t get what i have to change to select the place.

THANKS!