How to enable VoLTE in Lollipop?

[kathanpatel1001]

I am tired of searching for root in marshmallow version. Can anyone guid how to downgrade to lollipop with steps to backup appropriate partitions so i don't loose imei or any other key parameters and also enable VoLTE on lollipop.

 

[ananthuthilakan]

I think its very difficult bcz lot of reference files for volte is present in the kernal which is inside the boot image , and marshmellow boot img and lolipop boot img has lot of difference