This seems to be just the prototype. Ideally, the production version would have the PCIe interface reader hardware on the system itself, and the SD Card would m

This seems to be just the prototype. Ideally, the production version would have the PCIe interface reader hardware on the system itself, and the SD Card would merely expose some bus pins. Another solution might be keeping the PCIe interface on the SD card but adding a small proxy in the reader to restrict the PCIe protocol - but this might incur a non-negligable performance hit.