Asrock Rack and Supermico sell AM4/AM5 motherboards with support for ECC UDIMMs. Other vendors might state official support on workstation-class motherboards, a

Asrock Rack and Supermico sell AM4/AM5 motherboards with support for ECC UDIMMs. Other vendors might state official support on workstation-class motherboards, and in general it might work even on motherboards without official support.