diff --git a/.gitignore b/.gitignore
index 772784fdb8c..6c8fbfbec84 100644
--- a/.gitignore
+++ b/.gitignore
@@ -183,3 +183,6 @@ lcov.info
 /keyman*.buildinfo
 /keyman*.changes
 /keyman*.tar.?z
+
+# flag file for build script
+.configured
diff --git a/common/tools/hextobin/build.sh b/common/tools/hextobin/build.sh
index 9e73f8c4101..073b008bf2e 100755
--- a/common/tools/hextobin/build.sh
+++ b/common/tools/hextobin/build.sh
@@ -11,7 +11,7 @@ THIS_SCRIPT="$(readlink -f "${BASH_SOURCE[0]}")"
 
 builder_describe "Build hextobin" clean configure build
 builder_describe_outputs \
-  configure /common/tools/hextobin/node_modules/commander \
+  configure /common/tools/hextobin/.configured \
   build     /common/tools/hextobin/build/index.js
 
 builder_parse "$@"
diff --git a/common/tools/hextobin/package.json b/common/tools/hextobin/package.json
index fb651481f7a..708dace5028 100644
--- a/common/tools/hextobin/package.json
+++ b/common/tools/hextobin/package.json
@@ -15,5 +15,8 @@
   "main": "build/index.js",
   "bin": {
     "hextobin": "build/hextobin.js"
+  },
+  "scripts": {
+    "postinstall": "echo configured > .configured"
   }
 }