Hi,
mokutil --sb-state shows for F24 and also for F23 "secure boot disabled". Going into bios (UEFI) shows under the option "boot mode" "secureboot UEFI enabled". F23 (same test configuration as F24) allows dual boot. This means in the F23 Grub boot menue Windows boot is ok. The usb flash medium for F24 previously I used for F22, also there were no boot problems.
Kind regards