diff --git a/internal/status/status.go b/internal/status/status.go
index 710223b8ded..e5c6513edd1 100644
--- a/internal/status/status.go
+++ b/internal/status/status.go
@@ -97,7 +97,7 @@ func (s *Status) Err() error {
 	if s.Code() == codes.OK {
 		return nil
 	}
-	return &Error{e: s.Proto()}
+	return &Error{s: s}
 }
 
 // WithDetails returns a new status with the provided details messages appended to the status.
@@ -136,19 +136,23 @@ func (s *Status) Details() []interface{} {
 	return details
 }
 
+func (s *Status) String() string {
+	return fmt.Sprintf("rpc error: code = %s desc = %s", s.Code(), s.Message())
+}
+
 // Error wraps a pointer of a status proto. It implements error and Status,
 // and a nil *Error should never be returned by this package.
 type Error struct {
-	e *spb.Status
+	s *Status
 }
 
 func (e *Error) Error() string {
-	return fmt.Sprintf("rpc error: code = %s desc = %s", codes.Code(e.e.GetCode()), e.e.GetMessage())
+	return e.s.String()
 }
 
 // GRPCStatus returns the Status represented by se.
 func (e *Error) GRPCStatus() *Status {
-	return FromProto(e.e)
+	return e.s
 }
 
 // Is implements future error.Is functionality.
@@ -158,5 +162,5 @@ func (e *Error) Is(target error) bool {
 	if !ok {
 		return false
 	}
-	return proto.Equal(e.e, tse.e)
+	return proto.Equal(e.s.s, tse.s.s)
 }
diff --git a/internal/transport/http2_client.go b/internal/transport/http2_client.go
index 9227b80150f..9592d443d3e 100644
--- a/internal/transport/http2_client.go
+++ b/internal/transport/http2_client.go
@@ -24,6 +24,7 @@ import (
 	"io"
 	"math"
 	"net"
+	"net/http"
 	"strconv"
 	"strings"
 	"sync"
@@ -1280,29 +1281,40 @@ func (t *http2Client) operateHeaders(frame *http2.MetaHeadersFrame) {
 		// that the peer is speaking gRPC and we are in gRPC mode.
 		isGRPC         = !initialHeader
 		mdata          = make(map[string][]string)
-		contentTypeErr string
+		contentTypeErr = "malformed header: missing HTTP content-type"
 		grpcMessage    string
 		statusGen      *status.Status
-
-		httpStatus string
-		rawStatus  string
+		httpStatusCode *int
+		httpStatusErr  string
+		rawStatusCode  = codes.Unknown
 		// headerError is set if an error is encountered while parsing the headers
 		headerError string
 	)
 
+	if initialHeader {
+		httpStatusErr = "malformed header: missing HTTP status"
+	}
+
 	for _, hf := range frame.Fields {
 		switch hf.Name {
 		case "content-type":
 			if _, validContentType := grpcutil.ContentSubtype(hf.Value); !validContentType {
-				contentTypeErr = fmt.Sprintf("transport: received the unexpected content-type %q", hf.Value)
+				contentTypeErr = fmt.Sprintf("transport: received unexpected content-type %q", hf.Value)
 				break
 			}
+			contentTypeErr = ""
 			mdata[hf.Name] = append(mdata[hf.Name], hf.Value)
 			isGRPC = true
 		case "grpc-encoding":
 			s.recvCompress = hf.Value
 		case "grpc-status":
-			rawStatus = hf.Value
+			code, err := strconv.ParseInt(hf.Value, 10, 32)
+			if err != nil {
+				se := status.New(codes.Internal, fmt.Sprintf("transport: malformed grpc-status: %v", err))
+				t.closeStream(s, se.Err(), true, http2.ErrCodeProtocol, se, nil, endStream)
+				return
+			}
+			rawStatusCode = codes.Code(uint32(code))
 		case "grpc-message":
 			grpcMessage = decodeGrpcMessage(hf.Value)
 		case "grpc-status-details-bin":
@@ -1312,7 +1324,27 @@ func (t *http2Client) operateHeaders(frame *http2.MetaHeadersFrame) {
 				headerError = fmt.Sprintf("transport: malformed grpc-status-details-bin: %v", err)
 			}
 		case ":status":
-			httpStatus = hf.Value
+			if hf.Value == "200" {
+				httpStatusErr = ""
+				statusCode := 200
+				httpStatusCode = &statusCode
+				break
+			}
+
+			c, err := strconv.ParseInt(hf.Value, 10, 32)
+			if err != nil {
+				se := status.New(codes.Internal, fmt.Sprintf("transport: malformed http-status: %v", err))
+				t.closeStream(s, se.Err(), true, http2.ErrCodeProtocol, se, nil, endStream)
+				return
+			}
+			statusCode := int(c)
+			httpStatusCode = &statusCode
+
+			httpStatusErr = fmt.Sprintf(
+				"unexpected HTTP status code received from server: %d (%s)",
+				statusCode,
+				http.StatusText(statusCode),
+			)
 		default:
 			if isReservedHeader(hf.Name) && !isWhitelistedHeader(hf.Name) {
 				break
@@ -1327,30 +1359,25 @@ func (t *http2Client) operateHeaders(frame *http2.MetaHeadersFrame) {
 		}
 	}
 
-	if !isGRPC {
-		var (
-			code           = codes.Internal // when header does not include HTTP status, return INTERNAL
-			httpStatusCode int
-		)
-
-		if httpStatus != "" {
-			c, err := strconv.ParseInt(httpStatus, 10, 32)
-			if err != nil {
-				se := status.New(codes.Internal, fmt.Sprintf("transport: malformed http-status: %v", err))
-				t.closeStream(s, se.Err(), true, http2.ErrCodeProtocol, se, nil, endStream)
-				return
-			}
-			httpStatusCode = int(c)
+	if !isGRPC || httpStatusErr != "" {
+		var code = codes.Internal // when header does not include HTTP status, return INTERNAL
 
+		if httpStatusCode != nil {
 			var ok bool
-			code, ok = HTTPStatusConvTab[httpStatusCode]
+			code, ok = HTTPStatusConvTab[*httpStatusCode]
 			if !ok {
 				code = codes.Unknown
 			}
 		}
-
+		var errs []string
+		if httpStatusErr != "" {
+			errs = append(errs, httpStatusErr)
+		}
+		if contentTypeErr != "" {
+			errs = append(errs, contentTypeErr)
+		}
 		// Verify the HTTP response is a 200.
-		se := status.New(code, constructHTTPErrMsg(&httpStatusCode, contentTypeErr))
+		se := status.New(code, strings.Join(errs, "; "))
 		t.closeStream(s, se.Err(), true, http2.ErrCodeProtocol, se, nil, endStream)
 		return
 	}
@@ -1407,16 +1434,6 @@ func (t *http2Client) operateHeaders(frame *http2.MetaHeadersFrame) {
 	}
 
 	if statusGen == nil {
-		rawStatusCode := codes.Unknown
-		if rawStatus != "" {
-			code, err := strconv.ParseInt(rawStatus, 10, 32)
-			if err != nil {
-				se := status.New(codes.Internal, fmt.Sprintf("transport: malformed grpc-status: %v", err))
-				t.closeStream(s, se.Err(), true, http2.ErrCodeProtocol, se, nil, endStream)
-				return
-			}
-			rawStatusCode = codes.Code(uint32(code))
-		}
 		statusGen = status.New(rawStatusCode, grpcMessage)
 	}
 
diff --git a/internal/transport/http_util.go b/internal/transport/http_util.go
index 15d775fca3c..d8247bcdf69 100644
--- a/internal/transport/http_util.go
+++ b/internal/transport/http_util.go
@@ -173,26 +173,6 @@ func decodeGRPCStatusDetails(rawDetails string) (*status.Status, error) {
 	return status.FromProto(st), nil
 }
 
-// constructErrMsg constructs error message to be returned in HTTP fallback mode.
-// Format: HTTP status code and its corresponding message + content-type error message.
-func constructHTTPErrMsg(httpStatus *int, contentTypeErr string) string {
-	var errMsgs []string
-
-	if httpStatus == nil {
-		errMsgs = append(errMsgs, "malformed header: missing HTTP status")
-	} else {
-		errMsgs = append(errMsgs, fmt.Sprintf("%s: HTTP status code %d", http.StatusText(*(httpStatus)), *httpStatus))
-	}
-
-	if contentTypeErr == "" {
-		errMsgs = append(errMsgs, "transport: missing content-type field")
-	} else {
-		errMsgs = append(errMsgs, contentTypeErr)
-	}
-
-	return strings.Join(errMsgs, "; ")
-}
-
 type timeoutUnit uint8
 
 const (
diff --git a/internal/transport/transport_test.go b/internal/transport/transport_test.go
index d50170cdf9b..92990eaf7b2 100644
--- a/internal/transport/transport_test.go
+++ b/internal/transport/transport_test.go
@@ -1978,6 +1978,31 @@ func (s) TestClientHandshakeInfo(t *testing.T) {
 }
 
 func (s) TestClientDecodeHeaderStatusErr(t *testing.T) {
+	testStream := func() *Stream {
+		return &Stream{
+			done:       make(chan struct{}),
+			headerChan: make(chan struct{}),
+			buf: &recvBuffer{
+				c:  make(chan recvMsg),
+				mu: sync.Mutex{},
+			},
+		}
+	}
+
+	testClient := func(ts *Stream) *http2Client {
+		return &http2Client{
+			mu: sync.Mutex{},
+			activeStreams: map[uint32]*Stream{
+				0: ts,
+			},
+			controlBuf: &controlBuffer{
+				ch:   make(chan struct{}),
+				done: make(chan struct{}),
+				list: &itemList{},
+			},
+		}
+	}
+
 	for _, test := range []struct {
 		name string
 		// input
@@ -1991,17 +2016,32 @@ func (s) TestClientDecodeHeaderStatusErr(t *testing.T) {
 				Fields: []hpack.HeaderField{
 					{Name: "content-type", Value: "application/grpc"},
 					{Name: "grpc-status", Value: "0"},
+					{Name: ":status", Value: "200"},
 				},
 			},
 			// no error
 			wantStatus: status.New(codes.OK, ""),
 		},
+		{
+			name: "missing content-type header",
+			metaHeaderFrame: &http2.MetaHeadersFrame{
+				Fields: []hpack.HeaderField{
+					{Name: "grpc-status", Value: "0"},
+					{Name: ":status", Value: "200"},
+				},
+			},
+			wantStatus: status.New(
+				codes.Unknown,
+				"malformed header: missing HTTP content-type",
+			),
+		},
 		{
 			name: "invalid grpc status header field",
 			metaHeaderFrame: &http2.MetaHeadersFrame{
 				Fields: []hpack.HeaderField{
 					{Name: "content-type", Value: "application/grpc"},
 					{Name: "grpc-status", Value: "xxxx"},
+					{Name: ":status", Value: "200"},
 				},
 			},
 			wantStatus: status.New(
@@ -2018,7 +2058,7 @@ func (s) TestClientDecodeHeaderStatusErr(t *testing.T) {
 			},
 			wantStatus: status.New(
 				codes.Internal,
-				": HTTP status code 0; transport: received the unexpected content-type \"application/json\"",
+				"malformed header: missing HTTP status; transport: received unexpected content-type \"application/json\"",
 			),
 		},
 		{
@@ -2045,27 +2085,56 @@ func (s) TestClientDecodeHeaderStatusErr(t *testing.T) {
 				"peer header list size exceeded limit",
 			),
 		},
+		{
+			name: "bad status in grpc mode",
+			metaHeaderFrame: &http2.MetaHeadersFrame{
+				Fields: []hpack.HeaderField{
+					{Name: "content-type", Value: "application/grpc"},
+					{Name: "grpc-status", Value: "0"},
+					{Name: ":status", Value: "504"},
+				},
+			},
+			wantStatus: status.New(
+				codes.Unavailable,
+				"unexpected HTTP status code received from server: 504 (Gateway Timeout)",
+			),
+		},
+		{
+			name: "missing http status",
+			metaHeaderFrame: &http2.MetaHeadersFrame{
+				Fields: []hpack.HeaderField{
+					{Name: "content-type", Value: "application/grpc"},
+				},
+			},
+			wantStatus: status.New(
+				codes.Internal,
+				"malformed header: missing HTTP status",
+			),
+		},
 	} {
+
 		t.Run(test.name, func(t *testing.T) {
-			ts := &Stream{
-				done:       make(chan struct{}),
-				headerChan: make(chan struct{}),
-				buf: &recvBuffer{
-					c:  make(chan recvMsg),
-					mu: sync.Mutex{},
+			ts := testStream()
+			s := testClient(ts)
+
+			test.metaHeaderFrame.HeadersFrame = &http2.HeadersFrame{
+				FrameHeader: http2.FrameHeader{
+					StreamID: 0,
 				},
 			}
-			s := &http2Client{
-				mu: sync.Mutex{},
-				activeStreams: map[uint32]*Stream{
-					0: ts,
-				},
-				controlBuf: &controlBuffer{
-					ch:   make(chan struct{}),
-					done: make(chan struct{}),
-					list: &itemList{},
-				},
+
+			s.operateHeaders(test.metaHeaderFrame)
+
+			got := ts.status
+			want := test.wantStatus
+			if got.Code() != want.Code() || got.Message() != want.Message() {
+				t.Fatalf("operateHeaders(%v); status = \ngot: %s\nwant: %s", test.metaHeaderFrame, got, want)
 			}
+		})
+		t.Run(fmt.Sprintf("%s-end_stream", test.name), func(t *testing.T) {
+			ts := testStream()
+			s := testClient(ts)
+
 			test.metaHeaderFrame.HeadersFrame = &http2.HeadersFrame{
 				FrameHeader: http2.FrameHeader{
 					StreamID: 0,
@@ -2078,7 +2147,7 @@ func (s) TestClientDecodeHeaderStatusErr(t *testing.T) {
 			got := ts.status
 			want := test.wantStatus
 			if got.Code() != want.Code() || got.Message() != want.Message() {
-				t.Fatalf("operateHeaders(%v); status = %v; want %v", test.metaHeaderFrame, got, want)
+				t.Fatalf("operateHeaders(%v); status = \ngot: %s\nwant: %s", test.metaHeaderFrame, got, want)
 			}
 		})
 	}
diff --git a/test/end2end_test.go b/test/end2end_test.go
index 1b839529c58..fc112bf21c3 100644
--- a/test/end2end_test.go
+++ b/test/end2end_test.go
@@ -7254,7 +7254,7 @@ func (s) TestHTTPHeaderFrameErrorHandlingInitialHeader(t *testing.T) {
 				":status", "403",
 				"content-type", "application/grpc",
 			},
-			errCode: codes.Unknown,
+			errCode: codes.PermissionDenied,
 		},
 		{
 			// malformed grpc-status.
@@ -7273,7 +7273,7 @@ func (s) TestHTTPHeaderFrameErrorHandlingInitialHeader(t *testing.T) {
 				"grpc-status", "0",
 				"grpc-tags-bin", "???",
 			},
-			errCode: codes.Internal,
+			errCode: codes.Unavailable,
 		},
 		{
 			// gRPC status error.
@@ -7282,14 +7282,14 @@ func (s) TestHTTPHeaderFrameErrorHandlingInitialHeader(t *testing.T) {
 				"content-type", "application/grpc",
 				"grpc-status", "3",
 			},
-			errCode: codes.InvalidArgument,
+			errCode: codes.Unavailable,
 		},
 	} {
 		doHTTPHeaderTest(t, test.errCode, test.header)
 	}
 }
 
-// Testing non-Trailers-only Trailers (delievered in second HEADERS frame)
+// Testing non-Trailers-only Trailers (delivered in second HEADERS frame)
 func (s) TestHTTPHeaderFrameErrorHandlingNormalTrailer(t *testing.T) {
 	for _, test := range []struct {
 		responseHeader []string
@@ -7305,7 +7305,7 @@ func (s) TestHTTPHeaderFrameErrorHandlingNormalTrailer(t *testing.T) {
 				// trailer missing grpc-status
 				":status", "502",
 			},
-			errCode: codes.Unknown,
+			errCode: codes.Unavailable,
 		},
 		{
 			responseHeader: []string{
@@ -7317,6 +7317,18 @@ func (s) TestHTTPHeaderFrameErrorHandlingNormalTrailer(t *testing.T) {
 				"grpc-status", "0",
 				"grpc-status-details-bin", "????",
 			},
+			errCode: codes.Unimplemented,
+		},
+		{
+			responseHeader: []string{
+				":status", "200",
+				"content-type", "application/grpc",
+			},
+			trailer: []string{
+				// malformed grpc-status-details-bin field
+				"grpc-status", "0",
+				"grpc-status-details-bin", "????",
+			},
 			errCode: codes.Internal,
 		},
 	} {