Here is a AM4 motherboard VRM list compiled by various people and testing results. Also which ones support BIOS flashing without a CPU. Not all, but most boards that will support the new Zen2 CPU’s are listed here. Just thought some info on this would be relevant, with Zen2 and X570 motherboards about to be released.
(https://docs.google.com/spreadsheets/d/1wmsTYK9Z3-jUX5LGRoFnsZYZiW1pfiDZnKCjaXyzd1o/htmlview#)