diff --git a/s3util/uploader.go b/s3util/uploader.go
index 1a21511..49fa918 100644
--- a/s3util/uploader.go
+++ b/s3util/uploader.go
@@ -3,15 +3,17 @@ package s3util
 import (
 	"bytes"
 	"encoding/xml"
-	"github.com/kr/s3"
 	"fmt"
 	"io"
 	"net/http"
 	"net/url"
 	"strconv"
+	"strings"
 	"sync"
 	"syscall"
 	"time"
+
+	"github.com/kr/s3"
 )
 
 // defined by amazon
@@ -190,11 +192,14 @@ func (u *uploader) putPart(p *part) error {
 	if resp.StatusCode != 200 {
 		return newRespError(resp)
 	}
-	s := resp.Header.Get("etag") // includes quote chars for some reason
-	if len(s) < 2 {
-		return fmt.Errorf("received invalid etag %q", s)
+
+	s := resp.Header.Get("etag")
+	s = strings.Trim(s, `"`) // includes quote chars for some reason
+	if s == "" {
+		return fmt.Errorf("received empty etag")
 	}
-	p.ETag = s[1 : len(s)-1]
+	p.ETag = s
+
 	return nil
 }
 
diff --git a/s3util/uploader_test.go b/s3util/uploader_test.go
index 77adbe8..ff32dd4 100644
--- a/s3util/uploader_test.go
+++ b/s3util/uploader_test.go
@@ -127,37 +127,44 @@ func TestEmptyEtag(t *testing.T) {
 			t.Fatal("uploader panic", err)
 		}
 	}()
-	body := readClose{
-		strings.NewReader(`<UploadId>foo</UploadId>`),
-		make(closeCounter, 100),
-	}
-	c := *DefaultConfig
-	c.Client = &http.Client{
-		Transport: RoundTripperFunc(func(req *http.Request) (*http.Response, error) {
-			resp := &http.Response{
-				StatusCode: 200,
-				Body: body,
-				Header: http.Header{
-					"Etag": {""},
-				},
-			}
-			return resp, nil
-		}),
-	}
-	u, err := newUploader("https://s3.amazonaws.com/foo/bar", nil, &c)
-	if err != nil {
-		t.Fatal("unexpected err", err)
-	}
-	const size = minPartSize + minPartSize/3
-	n, err := io.Copy(u, io.LimitReader(devZero, size))
-	if err == nil || err.Error() != `received invalid etag ""` {
-		t.Fatalf("expected err: %q", err)
-	}
-	if n != minPartSize {
-		t.Fatalf("wrote %d bytes want %d", n, minPartSize)
+
+	testEmptyEtag := func(emptyEtag string) {
+		body := readClose{
+			strings.NewReader(`<UploadId>foo</UploadId>`),
+			make(closeCounter, 100),
+		}
+		c := *DefaultConfig
+		c.Client = &http.Client{
+			Transport: RoundTripperFunc(func(req *http.Request) (*http.Response, error) {
+				resp := &http.Response{
+					StatusCode: 200,
+					Body:       body,
+					Header: http.Header{
+						"Etag": []string{emptyEtag},
+					},
+				}
+				return resp, nil
+			}),
+		}
+		u, err := newUploader("https://s3.amazonaws.com/foo/bar", nil, &c)
+		if err != nil {
+			t.Fatal("unexpected err", err)
+		}
+		const size = minPartSize + minPartSize/3
+		n, err := io.Copy(u, io.LimitReader(devZero, size))
+		if err == nil || err.Error() != `received empty etag` {
+			t.Fatalf("expected err: %q", err)
+		}
+		if n != minPartSize {
+			t.Fatalf("wrote %d bytes want %d", n, minPartSize)
+		}
+		err = u.Close()
+		if err == nil || err.Error() != `received empty etag` {
+			t.Fatalf("expected err: %q", err)
+		}
 	}
-	err = u.Close()
-	if err == nil || err.Error() != `received invalid etag ""` {
-		t.Fatalf("expected err: %q", err)
+
+	for _, emptyEtag := range []string{"", `""`} {
+		testEmptyEtag(emptyEtag)
 	}
 }