tw.blk.reset()

	modTime := hdr.ModTime
	if modTime.IsZero() {
		modTime = time.Unix(0, 0)
	}

	v7 := tw.blk.toV7()
	v7.typeFlag()[0] = hdr.Typeflag
	fmtStr(v7.name(), hdr.Name)
	fmtStr(v7.linkName(), hdr.Linkname)
	fmtNum(v7.mode(), hdr.Mode)
	fmtNum(v7.uid(), int64(hdr.Uid))
	fmtNum(v7.gid(), int64(hdr.Gid))