AMD has reportedly released new AGESA Microcode for Ryzen, which will improve RAM compatibility on their AM4 platform. This new code should be available soon in new UEFI/BIOS files for the AM4 motherboard, though the update will depend on how long it takes motherboard manufacturer to integrate this new code to their next UEFI/BIOS releases.
AMD’s Generic Encapsulated Software Architecture (AGESA), is a protocol that is used on AMD64 mainboards to initialise the system. The AGESA is responsible for the initialization of CPU cores, memory and HyperTransport controllers, which should mean that this new microcode will improve DDR4 memory support. So keep your eye on any new UEFI/BIOS update if you have an AM4 motherboard.