@the-owner
In game I cannot push two button simultaneously
The problem seems to be that you didn't turn on the ipega with X+Home and it's conflicting with your keyboard. Does this problem happen in other emulators?
I have no button to quit the game to main menu.
Firstly, Is it possible to take a combination of button and how is it coded ?
The default is start+select.
Secondly, maybe there is a line to add in "/opt/retropie/configs/all/retroarch-joypads/CONTROLLER-NAME.cfg" in order to add this action (quit a game to main menu) ?
That config file affect RetroArch only and the quit option is already there (default is start+select). I don't know how to config input for N64...
EDIT: check the docs and you'll find valuable info.