Note to self - setting AND keeping alternate boot device on  macOS

Having added a shiny new 256 GB SSD drive to my  Mac Mini ( this is a USB3 device as I didn't fancy opening up the Mini and replacing the in-built Fusion drive ), I needed a way to make the drive bootable.

I'd already used SuperDuper to clone the old drive to the new drive.

I just needed to work out how to (a) boot from it and (b) make the new drive the main drive.

This gave me the answers: -

How to select a different startup disk

Specifically this: -

Note this subtlety: -

Yes, it's all very well booting from the SSD, but no good if it then reverts back to the "spinning rust" that is the Fusion drive ( yes, I know it's a mix of disk and SSD ).

However, the other issue that I faced was that my Bluetooth keyboard ( connected via an external USB Bluetooth dongle ) did NOT allow me to press [Option] during the boot process.

This came to the rescue: -

How to manage OS X boot options with wireless keyboards

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however, if you use Apple's Bluetooth keyboard, you could find that the system may ignore these inputs and boot normally. While you might assume that these options require a USB keyboard or other physical connection

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Thankfully I had a wired USB keyboard, so I used that ….

The article does offer some other guidance: -

…

If any inputs are being sent via the Bluetooth keyboard before the controllers are active, then they will not be recognized by the system. However, if these inputs are performed after the controllers are activated, then they will be properly read. Therefore, for Bluetooth keyboards, be sure to press the desired key sequences after you hear the boot chimes and not before.

…

which is nice.

So I'm now booting from USB/SSD and the 2014 Mac Mini is suddenly WAY faster !