The latest BIOS should always be the first step - regardless of whether it is already compatible or not.
Reformat the USB stick with FAT32. Download BIOS from 08.04.2021. Rename to MSI.ROM. Copy only this file to an empty stick. Connect the board to the power supply (power supply to CPU_PWR1 and ATX_PWR1). Plug the USB into the Flash BIOS port on the back. Press Flash BIOS button to flash the BIOS and the LED of the button starts flashing.After the BIOS flash process is 100% complete, the LED goes off simultaneously. Ryzen 9 runs without problems.
https://de.msi.com/Motherboar...