I just built new PC based on Asus Z87-Plus motherboard and in BIOS boot menu I now have my removable devices listed twice - once as a device itself and once with "UEFI: " prefix.
It looks like this for Blu-ray drive on SATA port 5:
P5: PIONEER BD-RW BDR-208M (3523 MB)
UEFI: PIONEER BD-RW BDR-208M (3523 MB)
USB flash drives are similarly listed twice.
Hard drives are only listed once as non-UEFI.
What are the implications of picking UEFI boot option vs non-UEFI? Why aren't hard drives available in boot menu with UEFI option?