idk man, I just read about it on someones PC build description
''The X570 chipset was selected rather than the B450 chipset in order to bypass any BIOS update issues that would occur when combining a new Ryzen 3000 series (Zen 2) CPU with a B450 chipset. However, you are welcome to explore those options as well, but be forewarned that because it uses an older chipset, this motherboard may require a BIOS update before it will be compatible with the CPU. The manufacturer may have already updated the B450 BIOS before sending it to retailers, but if not, many motherboards cannot be updated without using an older CPU to do so.
If the motherboard is not updated, the PC is unlikely to boot at all with the new CPU. In this case, you would need to temporarily use an older CPU to update the motherboard BIOS before using a new CPU with it. The CPUs that could do this update would be the Ryzen 1000 CPUs, Ryzen 2000 APUs, and Ryzen 2000 CPUs.
If you stick with the X570 chipset on original part list provided, you will not have to deal with this process.''