I bought a 2 bay NAS and I plan to flash it with the TrueNAS operating system. As I was reading the installation instructions I came across a section that said one of the 2 drives will have to contain the boot/UEFI partition, and can therefore be used for nothing else. Am I reading this correctly? I have 2 4TB HDDs that I plan on using in both bays and I’ll have to use the entirety of one of those bays just to hold a small boot partition and nothing else?

There are also 4 slots available for M.2 NVMe SSDs so I’m looking at using a small SSD for my boot partition there if this is true. My apologies if this is a dumb question as I’m kind of new to this stuff.