If your goal is legitimate SIM file reading (ICCID, IMSI, ADM1), consider abandoning the SY-386 for a or Omnikey 3121 with modern open-source tools.
18;write_to_target_document7;default0;33c;18;write_to_target_document1a;_VGjuaYDHNIuO8L0PtcmCiQY_20;a5; Understanding "Connaitre Bootable" 0;16;
Yes, you can use a USB drive as a boot device. This is commonly done when installing or repairing an operating system.