diff --git a/src/cmd/prof/gopprof b/src/cmd/prof/gopprof
index 4e9212957df..dffeeffa13f 100755
--- a/src/cmd/prof/gopprof
+++ b/src/cmd/prof/gopprof
@@ -724,8 +724,10 @@ sub RunWeb {
     "firefox",
   );
   foreach my $b (@alt) {
-    if (system($b, $fname) == 0) {
-      return;
+    if (-f $b) {
+      if (system($b, $fname) == 0) {
+        return;
+      }
     }
   }
 
diff --git a/src/pkg/image/png/reader.go b/src/pkg/image/png/reader.go
index 33f00eb776f..fddb70423a7 100644
--- a/src/pkg/image/png/reader.go
+++ b/src/pkg/image/png/reader.go
@@ -14,7 +14,6 @@ import (
 	"image"
 	"io"
 	"os"
-	"strconv"
 )
 
 // Color type, as per the PNG spec.
@@ -109,7 +108,7 @@ func (d *decoder) parseIHDR(r io.Reader, crc hash.Hash32, length uint32) os.Erro
 	}
 	crc.Write(d.tmp[0:13])
 	if d.tmp[8] != 8 {
-		return UnsupportedError("bit depth " + strconv.Itoa(int(d.tmp[8])))
+		return UnsupportedError("bit depth")
 	}
 	if d.tmp[10] != 0 || d.tmp[11] != 0 || d.tmp[12] != 0 {
 		return UnsupportedError("compression, filter or interlace method")
diff --git a/src/pkg/rpc/client.go b/src/pkg/rpc/client.go
index e6a861a1e7a..d742d099fb3 100644
--- a/src/pkg/rpc/client.go
+++ b/src/pkg/rpc/client.go
@@ -93,13 +93,7 @@ func (client *Client) input() {
 		c := client.pending[seq]
 		client.pending[seq] = c, false
 		client.mutex.Unlock()
-		if c == nil {
-			err = os.NewError("invalid response sequence number")
-			break
-		}
 		err = client.codec.ReadResponseBody(c.Reply)
-		// TODO(rsc): Should look at err, but breaks tests.
-
 		// Empty strings should turn into nil os.Errors
 		if response.Error != "" {
 			c.Error = os.ErrorString(response.Error)
diff --git a/src/pkg/rpc/jsonrpc/all_test.go b/src/pkg/rpc/jsonrpc/all_test.go
index 5422cc72876..e94c594da0b 100644
--- a/src/pkg/rpc/jsonrpc/all_test.go
+++ b/src/pkg/rpc/jsonrpc/all_test.go
@@ -58,8 +58,7 @@ func TestServer(t *testing.T) {
 
 	cli, srv := net.Pipe()
 	defer cli.Close()
-	var ci rpc.ClientInfo
-	go ServeConn(srv, &ci)
+	go ServeConn(srv)
 	dec := json.NewDecoder(cli)
 
 	// Send hand-coded requests to server, parse responses.
@@ -85,9 +84,8 @@ func TestServer(t *testing.T) {
 func TestClient(t *testing.T) {
 	// Assume server is okay (TestServer is above).
 	// Test client against server.
-	var ci rpc.ClientInfo
 	cli, srv := net.Pipe()
-	go ServeConn(srv, &ci)
+	go ServeConn(srv)
 
 	client := NewClient(cli)
 	defer client.Close()
diff --git a/src/pkg/rpc/jsonrpc/server.go b/src/pkg/rpc/jsonrpc/server.go
index 40b50187746..9f3472a39c4 100644
--- a/src/pkg/rpc/jsonrpc/server.go
+++ b/src/pkg/rpc/jsonrpc/server.go
@@ -118,6 +118,6 @@ func (c *serverCodec) Close() os.Error {
 // ServeConn runs the JSON-RPC server on a single connection.
 // ServeConn blocks, serving the connection until the client hangs up.
 // The caller typically invokes ServeConn in a go statement.
-func ServeConn(conn io.ReadWriteCloser, ci *rpc.ClientInfo) {
-	rpc.ServeCodec(NewServerCodec(conn), ci)
+func ServeConn(conn io.ReadWriteCloser) {
+	rpc.ServeCodec(NewServerCodec(conn))
 }
diff --git a/src/pkg/rpc/server.go b/src/pkg/rpc/server.go
index 7df89a8d7a3..f7fce45a14b 100644
--- a/src/pkg/rpc/server.go
+++ b/src/pkg/rpc/server.go
@@ -214,7 +214,7 @@ func (server *serverType) register(rcvr interface{}) os.Error {
 		}
 		// Method needs three ins: receiver, *args, *reply.
 		// The args and reply must be structs until gobs are more general.
-		if mtype.NumIn() != 3 && mtype.NumIn() != 4 {
+		if mtype.NumIn() != 3 {
 			log.Stderr("method", mname, "has wrong number of ins:", mtype.NumIn())
 			continue
 		}
@@ -301,19 +301,13 @@ func sendResponse(sending *sync.Mutex, req *Request, reply interface{}, codec Se
 	sending.Unlock()
 }
 
-func (s *service) call(sending *sync.Mutex, mtype *methodType, req *Request, argv, replyv reflect.Value, codec ServerCodec, ci *ClientInfo) {
+func (s *service) call(sending *sync.Mutex, mtype *methodType, req *Request, argv, replyv reflect.Value, codec ServerCodec) {
 	mtype.Lock()
 	mtype.numCalls++
 	mtype.Unlock()
 	function := mtype.method.Func
 	// Invoke the method, providing a new value for the reply.
-	var args []reflect.Value
-	if mtype.method.Type.NumIn() == 3 {
-		args = []reflect.Value{s.rcvr, argv, replyv}
-	} else {
-		args = []reflect.Value{s.rcvr, argv, replyv, reflect.NewValue(ci)}
-	}
-	returnValues := function.Call(args)
+	returnValues := function.Call([]reflect.Value{s.rcvr, argv, replyv})
 	// The return value for the method is an os.Error.
 	errInter := returnValues[0].Interface()
 	errmsg := ""
@@ -348,7 +342,7 @@ func (c *gobServerCodec) Close() os.Error {
 	return c.rwc.Close()
 }
 
-func (server *serverType) input(codec ServerCodec, ci *ClientInfo) {
+func (server *serverType) input(codec ServerCodec) {
 	sending := new(sync.Mutex)
 	for {
 		// Grab the request header.
@@ -395,7 +389,7 @@ func (server *serverType) input(codec ServerCodec, ci *ClientInfo) {
 			sendResponse(sending, req, replyv.Interface(), codec, err.String())
 			break
 		}
-		go service.call(sending, mtype, req, argv, replyv, codec, ci)
+		go service.call(sending, mtype, req, argv, replyv, codec)
 	}
 	codec.Close()
 }
@@ -406,7 +400,7 @@ func (server *serverType) accept(lis net.Listener) {
 		if err != nil {
 			log.Exit("rpc.Serve: accept:", err.String()) // TODO(r): exit?
 		}
-		go ServeConn(conn, &ClientInfo{conn.LocalAddr().String(), conn.RemoteAddr().String()})
+		go ServeConn(conn)
 	}
 }
 
@@ -438,14 +432,14 @@ type ServerCodec interface {
 // The caller typically invokes ServeConn in a go statement.
 // ServeConn uses the gob wire format (see package gob) on the
 // connection.  To use an alternate codec, use ServeCodec.
-func ServeConn(conn io.ReadWriteCloser, ci *ClientInfo) {
-	ServeCodec(&gobServerCodec{conn, gob.NewDecoder(conn), gob.NewEncoder(conn)}, ci)
+func ServeConn(conn io.ReadWriteCloser) {
+	ServeCodec(&gobServerCodec{conn, gob.NewDecoder(conn), gob.NewEncoder(conn)})
 }
 
 // ServeCodec is like ServeConn but uses the specified codec to
 // decode requests and encode responses.
-func ServeCodec(codec ServerCodec, ci *ClientInfo) {
-	server.input(codec, ci)
+func ServeCodec(codec ServerCodec) {
+	server.input(codec)
 }
 
 // Accept accepts connections on the listener and serves requests
@@ -471,11 +465,7 @@ func serveHTTP(c *http.Conn, req *http.Request) {
 		return
 	}
 	io.WriteString(conn, "HTTP/1.0 "+connected+"\n\n")
-	ci := &ClientInfo{
-		LocalAddr:  conn.(net.Conn).LocalAddr().String(),
-		RemoteAddr: c.RemoteAddr,
-	}
-	ServeConn(conn, ci)
+	ServeConn(conn)
 }
 
 // HandleHTTP registers an HTTP handler for RPC messages.
diff --git a/test/arm-pass.txt b/test/arm-pass.txt
index d96b15c8e05..8878f6dc8d5 100644
--- a/test/arm-pass.txt
+++ b/test/arm-pass.txt
@@ -48,6 +48,7 @@
 # ./gc.go
 # ./gc1.go
 ./hashmap.go
+./hilbert.go
 ./helloworld.go
 ./if.go
 ./if1.go
@@ -331,6 +332,7 @@ fixedbugs/bug149.go
 fixedbugs/bug150.go
 fixedbugs/bug151.go
 fixedbugs/bug152.go
+fixedbugs/bug153.go
 # fixedbugs/bug154.go  # needs floating point
 fixedbugs/bug155.go
 fixedbugs/bug156.go