There are already BIOS for the older gen boards to support the new Ryzen CPU's just check your board model on the web site. These are not the new BIOS layout yet though.
I see the F40 bios for my X370 gaming K5 with 1.0.0.2 AGESA for Zen2 chips, is there any plans for the 1.0.0.3 people have been talking about for x370 & x470 boards?