Yeh smart switch can't do it, you need to flash oreo back onto the phone and need to use software called Odin and a pc. Be warned though it can go wrong and the answers from Google are out if date.
I have a note 8 and the other half has a s9+.
We were both in the beta and had no issues but our phones dont seem to have upgraded to the official final version.
Is there something we need to do or should it of upgraded automatically?
Thanks in advance for any advice.