M2 slot disabled for launch.
This removes some of our thoughts that they would/could support slower drives for PS4 titles etc. It looks like certified only going in there.
https://www.theverge.com/2020/11/5/21551165/sony-ps5-playstation-5-no-m2-ssd-expansion-launch
From that blurb, the NVME manufacturers say compatibility testing program hasn't started. I'm still not sure if Sony is going to have one [an official whitelist of drives].
I spoke to practically every manufacturer of a PCIe Gen4 stick drive — there is only a handful — and not a single one was able to tell me their drives will actually work with the PS5. Two suggested that Sony’s compatibility testing program hasn’t actually kicked off yet.
Several were optimistic, though, suggesting that their drives should meet Sony’s requirements, and we’re hoping to test for ourselves as soon as we get a chance.