https://wccftech.com/amd-ryzen-zen-3-cpu-support-asus-300-series-motherboards-using-asrock-400-series-bios/

ASUS ROG forum members have found a bizarre way of enabling support for AMD Ryzen 'Zen 3' Desktop CPUs on their ASUS X370 series motherboards using BIOS from ASRock's B450 boards.

It's quite mind-boggling to see people going to these extends to enable support for a certain line of processors on their motherboards that aren't officially supported. The main issue is that AMD itself had blocked motherboard manufacturers from offering Ryzen 5000 'Zen 3' Desktop CPUs support on older X370 motherboards. This meant that users of ASUS motherboards & various other brands were cut off from a generation of processors which they were initially said to get support for.