How do I duplicate my phone onto another? (not data)

[Android Central Question]

I have a LeEco 1s phone that works pretty well with Android 6
I have a second identical phone where I've played around with custom roms but it only has Android 5 and is missing features.
I have been unable to locate a usable, v6 original ROM for this phone as the company has now faded away...
I want to backup the v6 phone and restore it to the v5 phone (data is not important - the v6 will be reset pre-copy) and end up with a second v6 phone.
Can anyone help me with this?

 

[VidJunky]

Welcome to Android Central. Here in the general Ask a Question section you're not likely to find an answer to such a specific question, especially dealing with ROMs and rooting. Become a member and check out the Rooting and ROM section here. You may also want to check out the XDA Developers web site. There a large part of their members root and play with ROMs on Android. I would recommend becoming a member there also because I see a lot of specific questions about root and ROMs just sit in the general Q and A section. Becoming a member at either site is free, only takes a few minutes to set-up and it allows you to have two way conversations with the community making getting help much easier.