The latest BIOS release for the Asus mainboards that use the AMD B350 and X370 chipsets comes with a description that mentions "new upcoming processors" without naming them. However, it is almost certain that the update comes to accommodate a new wave of AMD desktop processors with integrated Vega graphics.
https://www.notebookcheck.net/Upcoming-AMD-Ryzen-processors-spotted-in-BIOS-updates-for-B350-X370-mainboards.264276.0.html