FWIW I ran 2400g on a B550 mobo for awhile while i was waiting on the 5600G launch. I know it is not the same but B550 does not officially support Zen1 CPUs/APUs. I was a bit wary updating the BIOS but slowly but surely I update to the latest bios, flashing just about every bios in between. They all worked fine.
Also PBO is working on my original 2400G mobo - Asrock AB350M. 300 series chipsets are not supposed to support PBO. But I have PBO and Curve Optimizer maxed out at +200 on 3600(nonX). The kicker is that the mobo eventually got bios support for BCLK OC as well. So I am running the 3600 at 104MHz BCLK and +208MHz (+2 multi) with turbo (4575MHz) fully functional. This works with both X370m and AB350m bioses flashed on the mobo.
Moral of the story is, AMD artificially limits the support and I believe for mobo manufacturers it is easier to compile newer bioses off the same base code so there is cross support for all the different generations.
Also PBO is working on my original 2400G mobo - Asrock AB350M. 300 series chipsets are not supposed to support PBO. But I have PBO and Curve Optimizer maxed out at +200 on 3600(nonX). The kicker is that the mobo eventually got bios support for BCLK OC as well. So I am running the 3600 at 104MHz BCLK and +208MHz (+2 multi) with turbo (4575MHz) fully functional. This works with both X370m and AB350m bioses flashed on the mobo.
Moral of the story is, AMD artificially limits the support and I believe for mobo manufacturers it is easier to compile newer bioses off the same base code so there is cross support for all the different generations.