Sharing partial with the "main" app?

I've "Integrated Toto and a Rails app in 10 steps" sucessfully, and I manage to use shared assets (js, css and the like).
BUT I struggle to use partials from my main app within the Toto layout template (render partial fails with an argument error, "1 for 2").
Is there a good / recommended way to share layout and partials between the main Rails app and an integrated Toto blog?
My objective is to not replicate the template code of the main application for using it in the Toto blog.

Thanks!

No files or tests are named. Start by reviewing the Rails/Toto integration described in the issue and the layout partial-rendering entry point, then reproduce the reported “1 for 2” argument error. Done means the Toto blog can reuse the main Rails app’s layout and partials without duplicating template code.

Written by the indexing model from the issue text.