One more detail. I have one computer with a sophisticated BIOS; it can boot a USB stick in UEFI-mode or non-UEFI mode. On that computer, the bootable USB stick worked when booted in UEFI-mode and failed in non-UEFI mode with the same "Boot Error" as everything else.
(To be explicit: the bootable USB stick was created by usb-creator, and contained Ubuntu GNOME 15.10 daily from 2015/10/10, 64-bit.)
One more detail. I have one computer with a sophisticated BIOS; it can boot a USB stick in UEFI-mode or non-UEFI mode. On that computer, the bootable USB stick worked when booted in UEFI-mode and failed in non-UEFI mode with the same "Boot Error" as everything else.
(To be explicit: the bootable USB stick was created by usb-creator, and contained Ubuntu GNOME 15.10 daily from 2015/10/10, 64-bit.)