Hello ,
If you have any other working device , you can connect the USB device to it , take the snapshot from that device and then connect it to the faulty one and reboot . Boot priority of USB is higer than CF , so it should take over . Once its up copy the Snapshot from USB to CF .
In working one connect the USB ( not more than 4 Gb and with FAT32 format :
> request system snaphot media usb
In non working one once it boots from USB .
> request system snapshot media internal .
But no ganrentee on the configuration since its will fresh new configuration or the configuration from the device that you took snapshot .