Sorry if this doesn’t help those having difficulties but I’ve posted elsewhere trying to assist those trying to downgrade from 2.0 to 1.8. I’m wondering whether the same solution may help those in this thread who are having difficulties with the upgrade.
I had to leave the Roon remote legacy connected to my Nucleus in order for the downgrade to 1.8 legacy on the Nucleus to work. It’s possible you may have to do something similar (i.e., leave the version 2.0 remote connected to the Nucleus) when trying to upgrade the Nucleus to version 2.0 in the manner you’ve been describing.
Sorry if this is not helpful in your context!
Stephen