When the BIOS is fully functional, Awdflash (for Award) and AMIflash (for AMI) works correctly because they call some BIOS routine which does the unprotect. When the BIOS is not OK, UniFlash is needed
Actually, it's not very intelligent - it checks if the Power Management controller of Intel PIIX4 south bridge has a base address configured. If not, it forces the base address to $6100 (this is unsafe because this might cause conflict with another device) and then changes the state of two GPO pins - one for the M715 and another one for BX133-RAID board. Strange things might happen if these GPOs are used for other purposes on another board.