diff --git a/action.js b/action.js
index 09df795..1938f1f 100644
--- a/action.js
+++ b/action.js
@@ -10,7 +10,7 @@ const packageJsonUrls = [];
 // Get system utils
 execSync("apt update", { encoding: "utf8" });
 execSync("apt install -y pipx", { encoding: "utf8" });
-execSync("pipx install mpy-cross", { encoding: "utf8" });
+execSync("pipx install mpy-cross-v6.3", { encoding: "utf8" });
 
 // create base lib dir
 mkdirSync(libName);