A 5-port SATA board for a Raspberry Pi 4 Model B is possible, but not through the 40-pin HAT connector alone—the Pi 4 does not expose PCIe or USB 3 on that header.
The practical architecture is:
Pi 4 USB 3 Type-A port
│ short USB 3 cable
▼
USB 3 hub controller
├── USB-to-SATA bridge → SATA 1
├── USB-to-SATA bridge → SATA 2
├── USB-to-SATA bridge → SATA 3
├── USB-to-SATA bridge → SATA 4
└── USB-to-SATA bridge → SATA 5
Important constraints
- All five drives share one Pi USB 3 link, so aggregate throughput is limited to roughly 300–400 MB/s in practice, not five independent SATA-speed channels.
- The board needs an external power supply. The Pi header cannot power five drives.
- Five 2.5-inch drives can require substantial 5V startup current; 3.5-inch drives additionally require 12V.
- Each SATA port needs power control/protection, decoupling, and correctly routed high-speed differential pairs.
- A USB 3 cable must connect the board to one of the Pi’s blue USB-A ports; GPIO can optionally handle drive-power control and status.
- Linux compatibility depends on choosing USB-to-SATA bridges with reliable UASP, SMART, and unique serial-number support.
A cleaner high-performance product would use a Compute Module 4 carrier, where exposed PCIe can feed a PCIe switch and SATA controllers. For an Amazon Pi 4 Model B, however, the USB-hub architecture is the realistic option.
To design it, I need two decisions:
- 2.5-inch SATA drives, 3.5-inch drives, or both?
- Should the board also power the Pi from the same external supply?
Component selection, datasheet verification, schematic capture, and PCB layout require Agent mode.