[pdurrant]

Data kept in one place is data that will be lost.

Keeping your manually updated and corrected metadata about your ebooks only on a single SD Card is foolish.

It might just work, although the interface in any ereader to books in a calibre database is unlikely to be pleasant.

Your best option is to keep your calbre library on your main computer storage (which I hope is being backed up), and use the export function to write the books to an SD Card in a folder structure that will best suit using it in your chosen ereader.

SDCards are cheap. I would expect that you feel your time spent organising the metadata of your ebook collection is not.

Stating that those who try to give advice in response to your question are bragging is rude. Please try not to do that on MobileRead.