For “local update” I am talking about this feature:
https://en-americas-support.nintend.../how-to-update-software-data-via-a-local-user
It is the only way I have heard of to have an unmodified switch install an update that isn’t latest version, but it requires a second switch that currently has that game version with that game version being the highest installed version between the two switches. Notice it says that neither switch needs an internet connection, it doesn’t download the latest version.
For the second part, I want to transfer my 1.0.0 sysnand save. The only thing I am using emunand for is to use “local update”. If I have a clean Sysnand and transfer an unmodified save from it that should be safe, right?