small error in *ino sketch

bool isValidFNC(uint8_t f)
{
  bool rtn = true;  **<<<< this should be false?**
  switch(f) {
    case FN_DISK_RESET:
    case FN_DISK_SELECT:
    case FN_DISK_READ_SECTOR:
    case FN_DISK_WRITE_SECTOR:
    case FN_DISK_WRITE_HST:
    case FN_DISK_COPY:
    case FN_DISK_FORMAT:
    case FN_IMAGE_CMDS:
      rtn = true;
      break;
    default:
      break;
  }
  return rtn;
}