I had just posted the notes below on another thread for someone who wasn't familiar with the SD card build process.
Hi JFBUK,
I've just run through the process with a new SD card, as its been a while since I last did one.
Downloaded B2BNOV2019.zip
Plugged new SD card into PC
Fired up 'balenaEtcher' application on PC
Pointed 'balenaEtcher' to the B2BNOV2019.zip file (DON'T unzip the file)
Clicked on balenaEtcher 'Start' button
Took 'balenaEtcher a few minutes to flash and verify the SD card.
On my B2 (it's an older model with the SD card sticking out of the side; very handy), I swapped the new SD card into it.
Powered up the B2
Checked on software version which showed as 'B2B Nov 06 2019'
Ran a 'Web Upgrade' to the latest software on the Brennan website
B2 rebooted
Ran a software version check - now showing 'B2B May 23 2020'
Ran 'Setting' --> 'Maintenance' --> 'Advanced' --> ''Get Librespot'
B2 rebooted
Ran a software version check - still showing 'B2B May 23 2020'
So from a bare SD card to full upgrade including Librespot took less than 30 minutes to complete.
Regards,
Peter.