bootable backups not showing on power boot
 

I have a second backup disk that I just installed on my machine (M1 2021 iMac Monterey) (thanks to Dave for helping me get through an issue with an odd USB hub arrangement the disk was connected to). SuperDuper reports that it made that disk bootable, and the disk is properly mounted, but upon "Power Boot, that disk does not show up as a boot option. My original backup disks do. What's going on? This new disk was backed up with Erase then Copy, and at least at a glance, it looks like everything is on it. Why does my Mac not recognize it as a bootable disk?

Is it hooked directly to the Mac when you do this, or is it attached to a hub?

OK, sigh, it all works now. My mouse was connected to my powered USB hub, and on Power Boot it froze. When the mouse cursor froze, all the boot options didn't come up. I have rearranged so now I have mouse control on Power Boot, and all my bootable disk options come up. SuperDuper bootables are all fine. Another example of powered USB hub hell.

Yup. Keep trying to tell you...