code: def update_segment(self, selector, base, size, perms):
          
          logger.info("Updating selector %s to 0x%02x (%s bytes) (%s)", selector, base, size, perms)
          if selector == 99:
              self.set_fs(base)
          else:
              logger.error("No way to write segment: %d", selector)
docs: Only useful for setting FS right now.