diff --git a/backend/s3/s3.go b/backend/s3/s3.go
index 0c8795bc5..b5b7895fb 100644
--- a/backend/s3/s3.go
+++ b/backend/s3/s3.go
@@ -3,6 +3,7 @@ package s3
 import (
 	"bytes"
 	"errors"
+	"fmt"
 	"io"
 	"io/ioutil"
 	"os"
@@ -113,7 +114,7 @@ func (bb *s3Blob) Finalize(t backend.Type, name string) error {
 	}
 
 	<-bb.b.connChan
-	err = bb.b.s3api.PutObject(bb.b.bucketname, path, "application/octet-stream", int64(bb.buf.Len()), bb.buf)
+	err = bb.b.s3api.PutObject(bb.b.bucketname, path, "binary/octet-stream", int64(bb.buf.Len()), bb.buf)
 	bb.b.connChan <- struct{}{}
 	bb.buf.Reset()
 	return err
@@ -134,18 +135,34 @@ func (be *S3Backend) Create() (backend.Blob, error) {
 // name. The reader should be closed after draining it.
 func (be *S3Backend) Get(t backend.Type, name string) (io.ReadCloser, error) {
 	path := s3path(t, name)
-	r, _, err := be.s3api.GetObject(be.bucketname, path)
-	rc := ioutil.NopCloser(r)
+	rc, _, err := be.s3api.GetObject(be.bucketname, path)
 	return rc, err
 }
 
 // GetReader returns an io.ReadCloser for the Blob with the given name of
 // type t at offset and length. If length is 0, the reader reads until EOF.
 func (be *S3Backend) GetReader(t backend.Type, name string, offset, length uint) (io.ReadCloser, error) {
-	path := s3path(t, name)
-	r, _, err := be.s3api.GetPartialObject(be.bucketname, path, int64(offset), int64(length))
-	rc := ioutil.NopCloser(r)
-	return rc, err
+	rc, err := be.Get(t, name)
+	if err != nil {
+		return nil, err
+
+	}
+
+	n, errc := io.CopyN(ioutil.Discard, rc, int64(offset))
+	if errc != nil {
+		return nil, errc
+
+	} else if n != int64(offset) {
+		return nil, fmt.Errorf("less bytes read than expected, read: %d, expected: %d", n, offset)
+
+	}
+
+	if length == 0 {
+		return rc, nil
+
+	}
+
+	return backend.LimitReadCloser(rc, int64(length)), nil
 }
 
 // Test returns true if a blob of the given type and name exists in the backend.