BIOS can't detect two identical NVMEs?

I started using my Framework Desktop with two Samsung 990 PRO 1TB over two months ago, but only using one of them. Today I wanted to install Arch on the other one, so I booted from a USB stick, but couldn’t find the secondary SSD in /dev. There was only /dev/nvme0n1, the primary one.

I thought the secondary SSD was broken, so I took out the primary SSD and rebooted. To my surprise, the installation ISO detected the secondary SSD, and I was able to install Arch on it.

After reinstalling the primary SSD, I realized that I could no longer boot from it. In the BIOS boot device menu I see “Linux boot manager” and “EFI device”; selecting either one will boot Arch on the secondary SSD. /dev/nvme0n1 is the secondary SSD.

I have no other NVME with a different model, so I can’t tell if the issue is with two identical NVMEs or any two NVMEs in general.

Anyone with the same issue? Am I doing something wrong? Is there any temporary workaround? Thanks