Yesterday, AMD released half a dozen new Ryzen 5000 and 4000 series processors. These are meant to compete with Intel's 12th gen Alder Lake CPUs until Zen 4 is ready for action towards the later half of the year.
The new Ryzen 5000 parts are based on Zen 3 architecture and the Ryzen 4000 SKUs are built using Zen 2. There is also a new APU in the mix. Alongside these, AMD also revealed when it will release the Ryzen 7 5800X3D that packs a massive 96MB of L3 cache thanks to its 3D V-cache.
Perhaps even bigger news than this was the official announcement of support for Ryzen 5000, including these newly-released parts, on the first-gen 300 series Socket AM4 motherboards. AMD in its press release confirmed that "Selective BETA BIOS updates" would be rolling out in April. It is rumored to be the same AGESA 18.104.22.168 firmware that also fixes the fTPM stuttering issue.
Since then, Asus has shared the release dates for the compatible firmware. In fact, it is apparently happening earlier than that with the motherboard maker releasing compatible AGESA update on March 25.
While that is certainly exciting, there is no mention of the the popular B350 chipset on this support list. Also, as you may have noticed, support for the Ryzen 5 5500 is crossed on the image above on both X370 and A320 boards. While Asus does not mention any specific reason Gigabyte states that this, at least in the case of A320, is a BIOS Code limitation on AMD's part:
AMD A320 chipset motherboards do not support Ryzen™ 5 5500 processors for now, due to AMD BIOS code limitation.
Interestingly Gigabyte has also added that A320 users can already run all the new CPUs except for the aforementioned Ryzen 5500 model. And once again, there is no mention of B350 on Gigabyte's support list either.