diff --git a/ops/build.sh b/ops/build.sh
index c4c0987..7ffec5e 100755
--- a/ops/build.sh
+++ b/ops/build.sh
@@ -13,9 +13,10 @@ STAMP="bin/.golint.stamp"
 # is excluded -- fixtures are not compiled into the binary.
 current_stamp() {
   {
-    find . -type f ! -path '*/testdata/*' | sort | xargs shasum -a 256
-    shasum -a 256 .custom-gcl.yaml
-  } | shasum -a 256 | cut -d' ' -f1
+    find pkg/ -type f ! -path '*/testdata/*' | sort | xargs sha256sum
+    sha256sum .custom-gcl.yaml
+    sha256sum root.go
+  } | sha256sum | cut -d' ' -f1
 }
 
 if [ "$1" = "--if-needed" ] &&