A hobbyist turned former home‑automation kit into a testbed for Raspberry Pi 3 Model B units, aiming to boot them from SSD via USB. After a year of experimentation, he discovered that the older Model B requires an SD card to start, even when the OS resides on an external drive.

He followed the standard procedure: upgrade the OS, enable USB boot in config.txt, clone the SD image to the SSD with `dd`, then remove the card and reboot. The Model B+ succeeded immediately, but the Model B stalled until he left the SD card connected, revealing a boot‑dependency.

To confirm, he copied the boot directory from each SSD onto a freshly formatted SD, ensuring the cmdline.txt UUID matched. After rebooting, the Pi booted from the SSD alone. The experiment underscores the quirks of early Pi models and informs future deployments on legacy hardware in production environments and reliability today.