diff --git a/bof3_checksum b/bof3_checksum
new file mode 100755
index 0000000..a74aebe
Binary files /dev/null and b/bof3_checksum differ
diff --git a/main.cpp b/main.cpp
index 2a235e4..394ebce 100644
--- a/main.cpp
+++ b/main.cpp
@@ -74,8 +74,6 @@ void printBuffer()
 
 int calcChecksum()
 {
-    saveFile(filePath + ".bak");
-
     int sum = 0;
     for (int i = firstByte; i <= lastByte; i++)
     {
@@ -92,7 +90,8 @@ int main(int argc, char *argv[])
 {
     checkParameters(argc, argv);
     loadFile(filePath);
-    int sum = calcChecksum();
+    saveFile(filePath + ".bak");
+    calcChecksum();
     saveFile(filePath);
 
     //cout << hex;