diff --git a/examples/app_i2s_loopback_xvf3510/app_i2s_loopback.xc b/examples/app_i2s_loopback_xvf3510/app_i2s_loopback.xc
index 742b29db..e6d2423a 100644
--- a/examples/app_i2s_loopback_xvf3510/app_i2s_loopback.xc
+++ b/examples/app_i2s_loopback_xvf3510/app_i2s_loopback.xc
@@ -80,7 +80,8 @@ void loopback(chanend c_i2s)
         for (int i=0; i<NUM_USB_CHAN_OUT; i++) outuint(c_i2s, samps[i]);
         for (int i=0; i<NUM_USB_CHAN_IN; i++) samps[i] = inuint(c_i2s);
 
-        xscope_int(0, samps[0]);
+        samps[0] = 0xf0aaaaaa; //Test pattern for ch 0 (left)
+        //xscope_int(0, samps[0]);
     }
 }
 
diff --git a/examples/app_i2s_loopback_xvf3510/xua_conf.h b/examples/app_i2s_loopback_xvf3510/xua_conf.h
index aa0f877c..df3c818b 100644
--- a/examples/app_i2s_loopback_xvf3510/xua_conf.h
+++ b/examples/app_i2s_loopback_xvf3510/xua_conf.h
@@ -14,7 +14,7 @@
 #define XUD_TILE 1
 #define AUDIO_IO_TILE 0
 #define MIXER 0
-#define XUA_USB_EN 0
+#define XUA_USB_EN 1 //switch on transfer samples
 
 #define SPDIF_TX_INDEX 0
 #define VENDOR_STR "XMOS"