UEFI vs. BIOS: How Do They Differ? | phoenixNAP KB
How to show Legacy (Non UEFI) boot options (MSI B350 PC MATE motherboard, F11, boot menu) - YouTube
New UEFI BIOS updates for ASUS AMD motherboards W10 - A520, B550, X570 - 10 Boards - Includes AGESA V2 PI 1.2.0.1 NON-BETA and SAM/Resize Bar Support for Ryzen 3000 series CPUs. : r/Amd