Samsung PM871B on H370M Pro4 question

Hi guys!

I've removed the M.2 SATA Samsung PM871B that was installed in a Dell laptop. I wanted to install it on my ASRock H370M Pro4.

I've discovered that it works only on the second M.2 slot (the one near the WIFI M.2 slot).

Is it normal, or it should work on the M.2 fist slot, too?

I'd like to buy a NVMe 256gb (Integral M Series), would it be recognized by the board in the first M.2 slot?

Thanks in advance for the reply!

THanks a lot for the reply.

What I asked is if it's normal that the SATA M.2 Samsung PM871b doesn't work in M.2 first slot, while works in the second slot.

Thanks in advance for the reply!