DF_VALID
if ((dumphdr.dump_flags & DF_VALID) == 0 && !disregard_valid_flag)
corehdr.dump_flags &= ~DF_VALID;
dumphdr.dump_flags &= ~DF_VALID;
corehdr.dump_flags |= DF_COMPRESSED | DF_VALID;
dumphdr->dump_flags = DF_VALID | DF_COMPLETE | DF_LIVE | DF_COMPRESSED;