Prime X470-Pro not seeing 5800 (OEM) CPU. BIOS 6210.

I decided to upgrade my X470-Pro from a Ryzen 2600 to a Ryzen 5800 (OEM).  I had already flashed the MB a while ago to 6063. So I installed the 5800 CPU in and it won't post at all. I put the 2600 in again and boots fine.  I then upgrade to BIOS 6210...