Clip starts around 28:18 into the video:
https://youtu.be/1N2NCpZ6Otk?t=1698AMD before reversing course on their original decision to not support Zen 3 on B450 and X470 platforms it sounds like they first reached out to board partners to survey their thoughts. Apparently when AMD did this, "Asus was the least on board" with providing Zen 3 support while MSI pushed AMD the hardest.
Even with AMD's decision to reverse course this only means that AMD will develop the code that will enable Zen 3 support on these older platforms, it is still up to the board partners to implement the code into Bioses for their motherboards. What this means is that board partners may choose not implement the code for their boards or only provide support initially for only one or two iterations of the AGESA code AMD provides board partners.
For marketing it is likely that Asus will provide at least one bios to check a box that their motherboards "support" Ryzen 4000 CPUs. However given Asus's recent track record with lackluster bios support for X470 and even X570 boards we should not expect serious Bios support.
Thoughts on this?