Persist Settings in the Option menu

[Bruce]

Hello everyone,

I am sorry for the noob question and sorry if there is already a topic about this.
I am trying to setup an on/off option for summon cutscenes.

I've looked at the

Custom Menu tutorial from
Custom menu
which explains how to place the menu on the screen

and Custom Paused Menu tutorial from
Custom Paused Menu
I know how to detect the options screen with
update/updated.c

if(openborvariant("in_options")){
}

and more openborvariants in the manual

but I still don't know how to save this on/off option to the .sav file (I think...) :-(
Can someone please help me understand it?

Thank you so much

Update:
Nevermind, can get it from SORX and thanks to Kratus