That's more or less what I was looking for. There's a SATA adapter for $10: https://www.pine64.org/?product=rockpro64-pci-e-to-dual-sata-ii-interface-card https

That's more or less what I was looking for. There's a SATA adapter for $10: https://www.pine64.org/?product=rockpro64-pci-e-to-dual-sata-ii-interface-card https://www.pine64.org/?product=rockpro64-pci-e-to-dual-sata... However, I'm not sure how it would perform compared to my somewhat obsolete AMD Athlon II X2 260, and other posts have convinced me the power savings wouldn't necessarily be significant enough to pay for it.