The Asrock 370 boards officially support ECC, though I've read that various BIOS/UEFI versions don't: https://www.reddit.com/r/Amd/comments/655e7v/all_asrock_am4_... People are reporting that the Asrock 350 boards do too. Gigabyte lists some ECC modules on the compatibility list but some report that it isn't working right.