Thanks for Details, this really helpsHaving the same problem saying "device is not certified" when trying to add Google Play account.
Edit: Got it working by doing this:
- Clearing Google PlayStore/Google Services data.
- Sideloading an app (Device ID) to get my GSF ID.
- Then registering the ID here: https://www.google.com/android/uncertified/
- Reboot the phone and try to add account and it should work.