diff --git a/src/pkg/bytes/reader.go b/src/pkg/bytes/reader.go
index 8041a3b324..1151ffcd69 100644
--- a/src/pkg/bytes/reader.go
+++ b/src/pkg/bytes/reader.go
@@ -43,7 +43,6 @@ func (r *Reader) Read(b []byte) (n int, err error) {
 }
 
 func (r *Reader) ReadAt(b []byte, off int64) (n int, err error) {
-	r.prevRune = -1
 	if off < 0 {
 		return 0, errors.New("bytes: invalid offset")
 	}
diff --git a/src/pkg/bytes/reader_test.go b/src/pkg/bytes/reader_test.go
index 01cfa6deb5..fc502d7fe5 100644
--- a/src/pkg/bytes/reader_test.go
+++ b/src/pkg/bytes/reader_test.go
@@ -138,7 +138,6 @@ var UnreadRuneErrorTests = []struct {
 	f    func(*Reader)
 }{
 	{"Read", func(r *Reader) { r.Read([]byte{}) }},
-	{"ReadAt", func(r *Reader) { r.ReadAt([]byte{}, 0) }},
 	{"ReadByte", func(r *Reader) { r.ReadByte() }},
 	{"UnreadRune", func(r *Reader) { r.UnreadRune() }},
 	{"Seek", func(r *Reader) { r.Seek(0, 1) }},
diff --git a/src/pkg/strings/reader.go b/src/pkg/strings/reader.go
index df4d807120..75bf07b377 100644
--- a/src/pkg/strings/reader.go
+++ b/src/pkg/strings/reader.go
@@ -42,7 +42,6 @@ func (r *Reader) Read(b []byte) (n int, err error) {
 }
 
 func (r *Reader) ReadAt(b []byte, off int64) (n int, err error) {
-	r.prevRune = -1
 	if off < 0 {
 		return 0, errors.New("strings: invalid offset")
 	}
diff --git a/src/pkg/strings/strings_test.go b/src/pkg/strings/strings_test.go
index 5c38965775..8347818d59 100644
--- a/src/pkg/strings/strings_test.go
+++ b/src/pkg/strings/strings_test.go
@@ -863,7 +863,6 @@ var UnreadRuneErrorTests = []struct {
 	f    func(*Reader)
 }{
 	{"Read", func(r *Reader) { r.Read([]byte{}) }},
-	{"ReadAt", func(r *Reader) { r.ReadAt([]byte{}, 0) }},
 	{"ReadByte", func(r *Reader) { r.ReadByte() }},
 	{"UnreadRune", func(r *Reader) { r.UnreadRune() }},
 	{"Seek", func(r *Reader) { r.Seek(0, 1) }},