downloading firmware more than once

Is it a problem if I download the same firmware more than once – I wasn’t sure if it downloaded correctly the first time.

Shouldn’t be a problem. The firmware is made to install on top of whatever is in there already.

Are you using the updater or using the manual method described here?

Personally I think the updater is a waste of time since it phones home to SanDisk every time you boot up. Better to check once a month–or couple of months–and do it manually. 

In fact, if you’re using the auto-updater, you can’t download the same firmware more than once. It only downloads when there’s a newer version.