So, I finally got this working just a few minutes ago. There's a few steps, but I should be able to get you going.
Note: Any time something asks for su privileges, grant them. Especially if it's asking for 'Forever'.
1) You will want to use the latest
Dirty Unicorns rom. So, flash that, with the GApps they recommend, etc.
Make sure you do a factory wipe.
2) Update all the apps, including SuperSU (don't worry about the out of date su binary.)
3) Install
Magisk Manager. Go to the Install section, and attempt to install (this will fail, but it will save the magisk zip on the internal storage.
4) Reboot into recovery, and install the magisk v11.6 zip. (It should be under
/storage/emulated/0/MagiskManager/Magisk-v11.6.zip) Reboot.
5) Go into Magisk Manager -> Settings, and toggle 'Magisk Hide'.
6) Go into SuperSU (Settings -> SuperSU in this rom) and then go to Settings -> Full Unroot. Wait for this to finish. Reboot.
7) Got back into Magisk Manager, and then run the SafetyNet check. This will fail, but it should say, 'Basic Integrity: true'. (Previously that was false.)
8) Install Pokemon Go, login, and you're golden! :highfive:
For anyone looking to be able to use an old phone to GPS Spoof, the additional steps require are below. :angel:
9) Install
Fake GPS Joystick. Once it installs, tap 'start' in the upper right. This will ask if you want to enable Mock Locations in the Developer Settings. Click the link, and do what it said to do.
Voila, you're all set.
Now, a note. I've notice there's some real lag on this phone playing pokemon go, compared to the Nexus 5 my wife has. It's not unplayable but it is a little annoying.
