diff --git a/.gitignore b/.gitignore
index 9e1e1bbd..2a184d4e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -26,3 +26,5 @@ _build*
 .waf-*/
 build/
 host/xmosdfu/xmosdfu
+.build*
+*.pyc
diff --git a/host/xmosdfu/xmosdfu.cpp b/host/xmosdfu/xmosdfu.cpp
index 44093a0f..f573f6b0 100644
--- a/host/xmosdfu/xmosdfu.cpp
+++ b/host/xmosdfu/xmosdfu.cpp
@@ -318,6 +318,11 @@ int read_dfu_image(char *file)
             }
             break;
         }
+        else if (numBytes < 0)
+        {
+            fprintf(stderr,"dfu_upload error (%d)\n", numBytes);
+            break;
+        }
         fwrite(block_data, 1, block_size, outFile);
         block_count++;
     }
diff --git a/tests/.gitignore b/tests/.gitignore
new file mode 100644
index 00000000..f0bcfb69
--- /dev/null
+++ b/tests/.gitignore
@@ -0,0 +1 @@
+test_results.csv