Updating firmware

I think it's called firmware anyway. So I'm using Edge DS on OS-1.41 and I want to update it to the newer 1.45 version. To update it would I need to backup all of my stuff in the flashcart or will it remain unaffected by the update? Also, when I download the update where on the flashcart do I download it to? (Should I save over the OS-1.41 or no?)

it will not affect your games/saves. Yes you need to overwrite the existing OS files.