"A bootable device has not been detected"

My NUC was running normally on Big Sur, but I did a fresh install of Ventura. The install went normally and the machine worked normally following the upgrade.

But on subsequent boot attempts, I get stuck on "A bootable device has not been detected", even when USB sticks with EFI that is known to work, either on this NUC or my regular hack.

I haven't made any changes to the bios settings. In the UEFI Boot Priority page, the item "UEFI:USB:OpwenCore:PART 0:OS Bootloader" can be seen, so it...

Tonymacx86