diff --git a/src/cmd/internal/goobj2/objfile.go b/src/cmd/internal/goobj2/objfile.go
index 03b322da6c..e10ce43833 100644
--- a/src/cmd/internal/goobj2/objfile.go
+++ b/src/cmd/internal/goobj2/objfile.go
@@ -396,15 +396,6 @@ type Reader struct {
 	h     Header // keep block offsets
 }
 
-func NewReader(rd io.ReaderAt, off uint32) *Reader {
-	r := &Reader{rd: rd, start: off}
-	err := r.h.Read(r)
-	if err != nil {
-		return nil
-	}
-	return r
-}
-
 func NewReaderFromBytes(b []byte, readonly bool) *Reader {
 	r := &Reader{b: b, readonly: readonly, rd: bytes.NewReader(b), start: 0}
 	err := r.h.Read(r)
@@ -418,16 +409,8 @@ func (r *Reader) BytesAt(off uint32, len int) []byte {
 	if len == 0 {
 		return nil
 	}
-	if r.b != nil {
-		end := int(off) + len
-		return r.b[int(off):end:end]
-	}
-	b := make([]byte, len)
-	_, err := r.rd.ReadAt(b, int64(r.start+off))
-	if err != nil {
-		panic("corrupted input")
-	}
-	return b
+	end := int(off) + len
+	return r.b[int(off):end:end]
 }
 
 func (r *Reader) uint64At(off uint32) uint64 {
@@ -460,17 +443,9 @@ func (r *Reader) uint8At(off uint32) uint8 {
 
 func (r *Reader) StringAt(off uint32) string {
 	l := r.uint32At(off)
-	if r.b != nil {
-		b := r.b[off+4 : off+4+l]
-		if r.readonly {
-			return toString(b) // backed by RO memory, ok to make unsafe string
-		}
-		return string(b)
-	}
-	b := make([]byte, l)
-	n, err := r.rd.ReadAt(b, int64(r.start+off+4))
-	if n != int(l) || err != nil {
-		panic("corrupted input")
+	b := r.b[off+4 : off+4+l]
+	if r.readonly {
+		return toString(b) // backed by RO memory, ok to make unsafe string
 	}
 	return string(b)
 }