diff --git a/support/tock_support_cppcsp.h b/support/tock_support_cppcsp.h
index 361d786..a5cc48d 100644
--- a/support/tock_support_cppcsp.h
+++ b/support/tock_support_cppcsp.h
@@ -93,12 +93,12 @@ protected:
 				in >> c;
 				out << c;
 			}
-			out.flush();
 		}
 		catch (csp::PoisonException& e)
 		{
 			in.poison();
 		}
+		out.flush();
 	}
 public:
 	inline StreamWriter(std::ostream& _out,const csp::Chanin<uint8_t>& _in)
@@ -225,14 +225,21 @@ protected:
 			{
 				tockSendableArrayOfBytes aob(1,&c);
 				in >> aob;
-				out << c;
+				if (c == 255)
+				{
+					out.flush();
+				}
+				else
+				{
+					out << c;
+				}
 			}
-			out.flush();
 		}
 		catch (csp::PoisonException& e)
 		{
 			in.poison();
 		}
+		out.flush();
 	}
 public:
 	inline StreamWriterByteArray(std::ostream& _out,const csp::Chanin<tockSendableArrayOfBytes>& _in)
diff --git a/testcases/echo.occ b/testcases/echo.occ
index 3b1a32d..2cb9576 100644
--- a/testcases/echo.occ
+++ b/testcases/echo.occ
@@ -5,4 +5,5 @@ PROC echo(CHAN BYTE in, out)
       in ? c
       out ! c
       out ! c
+      out ! 255
 :