Asus Z170-Deluxe bios flashback?

Very dumb question: how can I flash a modded bios into my motherboard? My old Z77 had a flashback button, this one doesn’t. I tried putting the USB dongle in the back USB 2.0 port with right filename and turning on pc, but nothing happens…

Not all ASUS mainboards do support the USB Flashback feature.
You probably have to use another method to get a modded BIOS properly flashed.

Z170 Deluxe has bios flashback, and it’s supported just on the only back USB 2.0 port. Just I can’t understand how to start flashing…
Edit: Found it! It’s actually on the PCB of the mainboard…