How to add soft keys without crash?

So I remember on my Note 4 and S6, I add the qemu.hw.mainkeys=0 on my build prop and it never really worked on lollipop or marshmallow. Everytime I rebooted, my phone would crash and just keeps giving an error over and over...everytime I pressed ok.

I'm sure the devs know how to fix this since the custom roms for my Note 4 got rid of the error awhile back