I backed mine up to the tool box and put a blank card in. It doesn't do anything in response to the blank card...
No, because it's not expecting the card to be blank, but continue with the restore process anyway.
...I am not sure what the advantage is of backing it up if you can't access the backup.
The backups are stored on your PC and the advantage is that you can use your last backup to recover from a situation where your SD card data has become corrupted. As long as you have an SD card in the PC, you access backups by clicking backup and then the restore option in Toolbox.
My understanding was that the backup can only be put back on the original card, in case the data gets corrupted and you need to restore it. But if others have said they've been able to restore it to a different card, then I would like to know how it is done too.
a) Have travelled at least 63 miles (100km) with original Mazda SD Card installed, this ties the card to your car.
b) Switch off car, remove original card, insert original card into PC, download & install Mazda Toolbox.
c) Use backup option in Mazda Toolbox to backup card to PC.
Here's how I copied the original card to a larger capacity one a few months ago:-
1) Insert a blank SD Card (8GB or larger) into your PC.
2) Start Mazda Toolbox software, you do not need to be logged in to do the restore. The program will not recognise that a device / SD Card is connected if the card you're using is empty, just ignore that and click on the Backup button regardless.
3) Click a backup name from the list of available backups on your computer and click the corresponding Restore button.
4) You will get a pop-up message about not being able to recognise your device or card and that you can only restore to an original device or card. Just ignore that and click the Next button.
5) From the list presented, click the drive letter that corresponds to your SD Card and click the Next button.
6) The restore process begins. In my case it took just under 10 minutes to copy the files to the new SD Card.
7) When you get the message that says all of your files have restored successfully, click the Finish button.
8) Remove card from PC.
9) With the car switched off, insert the original or copied card into the SD Card slot in the car.