If this works for you make sure to Subscribe and like.
NOTE: This only works on cistern custom roms.
I tried this on a real phone and SELinux now works.
Sorry about that. I had trouble Explaining how to extract and repack boot.img
This is how to extract boot.Img
1. Click carliv
2. Press b (boot) and hit enter
3 select 1 and hit enter
4. Select 1 (Unpack image) and hit enter.
There. Now you have extracted boot.Img, A new folder will show up as Boot. And you can edit the androids Kernal.
This is how you repack boot.img
1. Click carliv
2. Press b (boot) and hit enter
3. select 1 and hit enter
4. Select 2 Repack image and hit enter.
A folder called output will show up and this folder will contain your edited boot.img
Now you can flash the new image through fast boot or TWRP