diff --git a/README.md b/README.md
index 96b4227..3793cfb 100644
--- a/README.md
+++ b/README.md
@@ -188,6 +188,7 @@ Security note:
 
 ```bash
 cd awg2_harness
+chmod +x ./tools/build.sh
 ./tools/build.sh --prepare-build-env --bootstrap-rust --yes
 ./tools/build.sh --package
 (cd dist && sha256sum -c SHA256SUMS)
diff --git a/tools/build.sh b/tools/build.sh
old mode 100644
new mode 100755
index 51fedbb..2622fa6
--- a/tools/build.sh
+++ b/tools/build.sh
@@ -305,7 +305,7 @@ validate_package_version() {
     echo "Package version must not be empty"
     exit 1
   fi
-  if [[ "$version" == *'/'* || "$version" == *'\'* ]]; then
+  if [[ "$version" == */* || "$version" == *\\* ]]; then
     echo "Package version must not contain path separators: $version"
     exit 1
   fi