Polar Trap :
I really wanna find this, as I'm thinking about getting a i5-7600k. If I can't flash the mobo, should I just get a 6600k? Thanks.
Did you try the obvious place, the ASUS website: https://www.asus.com/uk/Motherboards/SABERTOOTH-Z170-S/HelpDesk_Download/
1st select your OS, then select the submenu "BIOS"