FYI : if anyone that has Oreo and havent had any luck getting Viper to work properly, Root with Magisk and in the Downloads section of Magisk there are (2) Viper4Android mods, use the 1st Viper4Android FX v1.6.9 (Viper4Android v2.5.0.5). After downloading and installation of Magisk Viper4 Android, just reboot and your done, the module installs the drivers and the apk. I am currently on RR Neo 8.1.0 and i've only tested this method on RR, so i cannot say it works on every 8.1.0 build, But its super simple and again, had NO ISSUEs...