Mupen64Plus N64 Controller Start button mapped to "home" button

[pronane]

Hi,

I bought some generic usb N64 controllers for my nvidia shield using MupenPlus64.  
The problem I have is the "S" or "Start" button is mapped to my home button for the Nvidia shield.
I have tried unmapping but its not really a proper solution, and it didnt work the nvidia controllers didnt do anything when the home button was hit, but the "Start" button
on the N64 Controllers still returns home, so not sure how its mapped or what its actually mapped to.  

All the other buttons work fine, but I obviously need the start button.  Is it possible to create two buttons(say A&B) pressed together - long press) to map to the "Start" 
button of the controller?  I have tried this though and everytime I use an already existing button that is mapped it removes it from the previously mapped button even when 
its used in combination with another one for "Start".

Thanks
Paul

Edited December 14, 2022 by pronane