I downloaded Focal 64 and used dd to make a LiveUSB. However, it never booted. I was presented with Grub and other stuff in a console. I tried it a few times with the same result.
Then I realized that the BIOS of my laptop (Intel 3rd Generation Core processor, 8 GB memory) is set for legacy boot, which I won't change because of how I use it. So I downloaded Bionic 64 and used dd to make a LiveUSB. Success!
So I assume that Focal 64 and later releases will only work with UEFI BIOS. If there is another reason Focal 64 won't boot, I'd like to hear it.
Since Bionic 64 is based on Ubuntu, can I install it and later upgrade to Focal 64? Does Puppy have an Upgrade Manager like Ubuntu?