I DIRECT YOUR ATTENTION TO THIS THREAD INSTEAD: https://forum.xda-developers.com/mate-9/how-to/guide-how-to-root-mate-9-decrypt-data-t3569986
It's easier as you don't need to get a decrypted boot image.
Thank you ajsmsg78 for your work on this....
There seems to be a little confusion on how to do this and I've written down how to in many posts now so I figure I'd just write it down in a little guide.
What you need:
Firmware update.zip from http://pro-teammt.ru/firmware-database/
For rooting/decryption in general, check out: https://forum.xda-developers.com/mate-9/how-to/guide-how-to-root-mate-9-decrypt-data-t3569986
These require TWRP 3.1.0: https://forum.xda-developers.com/mate-9/development/recovery-uno...
This does not set selinux to permissive all the time, you have to use 'setenforce 0' to enable permissive, this is to only enable it when you need it.
All this does is let us use 'setenforce' again, since Huawei decided to disable it in Oreo.
Please note, this requires SELinux Permissive (included init.d script/instructions for PHH). It will not work on Enforcing, even with supolicy (I've tried. If anyone has an idea how to get it working with "soundserver" and setting supolicy "read w...