I think it's worth investigating the level of "support" these boards offer for ECC. The ASRock Taichi for example does not have any ECC DIMMs in its "qualified" list.
Interesting. Might be good for someone (not me!) to investigate then write in-depth info about. :)
As a data point, I'm using a previous generation ASRock AM4 motherboard with ECC and that definitely works.
I'm undervolting my cpu and ram, and very occasionally (every 6 months or so?) one of those seems to be generating a correctable ECC error that gets propagated to warning messages on my terminal. Haven't bothered investigating any further though. ;)
Among consumer products, some AMD desktop CPUs and motherboards support ECC memory, and that's about it.