Forein moun root topic

Hi,
I'm trying to root a recent Mediatek arm64 Lollipop ROM and get that not having a patched recovery is a real problem

But I Have a Factory ROM, with scatter file. So I can readback/reflash /system with flashtools.

This make me think I can root the ROM using a shell script after mount /system on a Linux (Ubuntu) PC replicating, at last, part of what SuperSU install script do.

I'll glad to read others ideas about that and what maybe the install method:
- Do a preroot work, reflash and install supersu from Google Play
- Do a full root work installing supersu in /system/app and let SuperSU autocheck finish it at first boot after reflash.

Thanks in advance,
--
Josemi