diff --git a/integration-tests/nghttpx_test.go b/integration-tests/nghttpx_test.go
index f646967b..189df0ad 100644
--- a/integration-tests/nghttpx_test.go
+++ b/integration-tests/nghttpx_test.go
@@ -9,6 +9,43 @@ import (
 	"testing"
 )
 
+func TestH1H1PlainGET(t *testing.T) {
+	st := newServerTester(nil, t, noopHandler)
+	defer st.Close()
+
+	res, err := st.http1(requestParam{
+		name: "TestH1H1PlainGET",
+	})
+	if err != nil {
+		t.Errorf("Error st.http1() = %v", err)
+	}
+
+	want := 200
+	if got := res.status; got != want {
+		t.Errorf("status = %v; want %v", got, want)
+	}
+}
+
+func TestH1H1PlainGETClose(t *testing.T) {
+	st := newServerTester(nil, t, noopHandler)
+	defer st.Close()
+
+	res, err := st.http1(requestParam{
+		name: "TestH1H1PlainGET",
+		header: []hpack.HeaderField{
+			pair("Connection", "close"),
+		},
+	})
+	if err != nil {
+		t.Fatalf("Error st.http1() = %v", err)
+	}
+
+	want := 200
+	if got := res.status; got != want {
+		t.Errorf("status = %v; want %v", got, want)
+	}
+}
+
 func TestH2H1PlainGET(t *testing.T) {
 	st := newServerTester(nil, t, noopHandler)
 	defer st.Close()
diff --git a/integration-tests/server_tester.go b/integration-tests/server_tester.go
index e4197e2d..6b859222 100644
--- a/integration-tests/server_tester.go
+++ b/integration-tests/server_tester.go
@@ -1,6 +1,7 @@
 package nghttp2
 
 import (
+	"bufio"
 	"bytes"
 	"crypto/tls"
 	"errors"
@@ -8,6 +9,8 @@ import (
 	"github.com/bradfitz/http2"
 	"github.com/bradfitz/http2/hpack"
 	"github.com/tatsuhiro-t/go-nghttp2"
+	"io"
+	"io/ioutil"
 	"net"
 	"net/http"
 	"net/http/httptest"
@@ -34,6 +37,7 @@ func pair(name, value string) hpack.HeaderField {
 type serverTester struct {
 	args          []string  // command-line arguments
 	cmd           *exec.Cmd // test frontend server process, which is test subject
+	url           string    // test frontend server URL
 	t             *testing.T
 	ts            *httptest.Server // backend server
 	conn          net.Conn         // connection to frontend server
@@ -87,6 +91,7 @@ func newServerTester(args []string, t *testing.T, handler http.HandlerFunc) *ser
 		cmd:          exec.Command(serverBin, args...),
 		t:            t,
 		ts:           ts,
+		url:          fmt.Sprintf("http://127.0.0.1:%v", serverPort),
 		nextStreamID: 1,
 		authority:    u.Host,
 		frCh:         make(chan http2.Frame),
@@ -165,6 +170,47 @@ type requestParam struct {
 	body      []byte              // request body
 }
 
+func (st *serverTester) http1(rp requestParam) (*serverResponse, error) {
+	method := "GET"
+	if rp.method != "" {
+		method = rp.method
+	}
+
+	var body io.Reader
+	if rp.body != nil {
+		body = bytes.NewBuffer(rp.body)
+	}
+	req, err := http.NewRequest(method, st.url, body)
+	if err != nil {
+		return nil, err
+	}
+	for _, h := range rp.header {
+		req.Header.Add(h.Name, h.Value)
+	}
+	req.Header.Add("Test-Case", rp.name)
+
+	if err := req.Write(st.conn); err != nil {
+		return nil, err
+	}
+	resp, err := http.ReadResponse(bufio.NewReader(st.conn), req)
+	if err != nil {
+		return nil, err
+	}
+	respBody, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+	resp.Body.Close()
+
+	res := &serverResponse{
+		status: resp.StatusCode,
+		header: resp.Header,
+		body:   respBody,
+	}
+
+	return res, nil
+}
+
 func (st *serverTester) http2(rp requestParam) (*serverResponse, error) {
 	res := &serverResponse{}
 	st.headerBlkBuf.Reset()
diff --git a/src/shrpx_https_upstream.cc b/src/shrpx_https_upstream.cc
index 7f6cdbd6..a51df58e 100644
--- a/src/shrpx_https_upstream.cc
+++ b/src/shrpx_https_upstream.cc
@@ -506,6 +506,11 @@ int HttpsUpstream::downstream_eof(DownstreamConnection *dconn) {
   if (LOG_ENABLED(INFO)) {
     DCLOG(INFO, dconn) << "EOF";
   }
+
+  if (downstream->get_response_state() == Downstream::MSG_COMPLETE) {
+    goto end;
+  }
+
   if (downstream->get_response_state() == Downstream::HEADER_COMPLETE) {
     // Server may indicate the end of the request by EOF
     if (LOG_ENABLED(INFO)) {
@@ -518,10 +523,11 @@ int HttpsUpstream::downstream_eof(DownstreamConnection *dconn) {
     goto end;
   }
 
-  if (downstream->get_response_state() != Downstream::MSG_COMPLETE) {
-    // error
+  if (downstream->get_response_state() == Downstream::INITIAL) {
+    // we did not send any response headers, so we can reply error
+    // message.
     if (LOG_ENABLED(INFO)) {
-      DCLOG(INFO, dconn) << "Treated as error";
+      DCLOG(INFO, dconn) << "Return error reply";
     }
     if (error_reply(502) != 0) {
       return -1;