I don't know which version, but it worked perfectly with the 3600, so it should already be 4.2, and if it is, a bios update is done in no time. But I would rather recommend a B550 for the CPU.
Well, I used this motherboard with a 3600x, so it is certainly 3rd gen compatible, even without flash in my case. Unfortunately, I don't know which bios version was installed.
Saletti
Yes, 1st Gen Ryzen go too. See:
https://www.asrock.com/MB/AMD/B450M-HDV%20R4.0/index.asp#CPU
Have fun. I've been using the board for several months now and for the price I'm really satisfied.