15 years or so ago I worked with iSCSI SANs; big boxes full of super fast hardware, lots of disks and expensive. Thinking back at that time I wondered: would it be possible to make a microcontroller into an iSCSI target? (a SAN on a microcontroller so to say) So I sat down and wrote a firmware for the cheap ESP32 to do so. And it works! You can now finally let your server boot from an SD-card (I connected an SD-card interface to the device for storage) over iSCSI. Not very fast (35 iops, 150kB/second (over WiFi)) but the proof of concept definitely works :-)