

My understanding is that hba cards support virtualization better than passing sata directly through. But if you’re not virtualizing the NAS, I wouldn’t see an issue with a reputable motherboard that has enough sata ports at 6 Gbps.
For the cheaper expansion cards I’d see that as a central point of failure and would recommend an hba card over a cheaper alternative.









I googled the echo flex and I don’t see any evidence someone has gotten the bootloader unlocked or have been able to install a custom ROM/OS. Depending on the generation the flex is based on, it could be Linux or android based. Have you been able to access the os on your devices? If not, you might have a lot of work on your hands to get enough access to install any kind of non-stock OS.