You can disable the SD slot in pfSense by hitting ESC at the bootloader and then typing these lines:set hint.sdhci_pci.0.disabled=1set hint.sdhci_pci.1.disabled=1bootOnce you are done installing you can permanently disable the SD slot by adding these lines to /boot/loader.conf.local:hint.sdhci_pci.0.disabled=1hint.sdhci_pci.1.disabled=1