Somewhere in this forum I did read a solution for ASUS mainboards without USB BIOS Flashback:
- download AI-Suite (when not for Win10 available use Version for 8.1)
- Start Easy Update for BIOS Update in Windows, select ORIGINAL file (then some timeconsuming checking seems to happen)
- before start flashing delete selected original file and replace with modded one (same name, same location).
- proceed with bios flash
I did this with some P8Z77-V LK, P8Z77-M, some ITX Z87 and ITX Z97 boards (all without USB-Flashback).
And previously did it while testing with a P8Z77-M Pro, a P8Z77-V Deluxe and a Z87I-Pro having USB-Flashback (in case of bricking while trying)
So no AFU /GAN or FTK or NVram-mod was needed.