How to distinguish multiple boards of the same type?

Cross-post:

When you plug an mbed-enabled board into a Windows PC, it pops up as a removable drive - with the drive name helpfully set to identify the type of board; eg,
image
Which is great if they are different types of board - as shown.

Not so much if you have more than one of the same type:

So how can we tell which one is which when we have more than one of the same type?

The Drive letter is no use - as that can change.

Any changes to the label are not saved - it reverts to default next time the board is plugged in.