Is it possible to modify a phone's hardware and software given that it has open source OS?

Question

I have a JioPhone with kaios in it. I came to know that it is a open source OS so I was wondering if one can add new things like keypad lock And volume buttons on it's side..
Or
create a 3d positioning system to track my hand's
movement and use it like a cursor

It's just a possibility that i thought of

so... is it possible?

Answer 1

Yes, it is possible...
PROVIDED you have permission to install a new OS.
First, get your hands on the sourcecode.
Modify it as per requirement and install it.
HOWEVER, it is impossible to modify the hardware if you are not Einstein.
Moreover, Jio phones use a customized version of KaiOS that is different from the open-sourced one.
So,...the chances are slim.