diff --git a/packages/plugin-legacy/README.md b/packages/plugin-legacy/README.md
index 0e40ccfe55f121..c2cfa4c45ef659 100644
--- a/packages/plugin-legacy/README.md
+++ b/packages/plugin-legacy/README.md
@@ -156,7 +156,7 @@ The legacy plugin requires inline scripts for [Safari 10.1 `nomodule` fix](https
 
 - `sha256-MS6/3FCg4WjP9gwgaBGwLpRCY6fZBgwmhVCdrPrNf3E=`
 - `sha256-tQjf8gvb2ROOMapIxFvFAYBeUJ0v1HCbOcSmDNXGtDo=`
-- `sha256-4y/gEB2/KIwZFTfNqwXJq4olzvmQ0S214m9jwKgNXoc=`
+- `sha256-8uUkKieevHiD3yYtzjkRvyDZWt+uZkBLuGEQWNiV3+c=`
 - `sha256-+5XkZFazzJo8n0iOP4ti/cLCMUudTf//Mzkb7xNPXIc=`
 
 <!--
diff --git a/packages/plugin-legacy/src/snippets.ts b/packages/plugin-legacy/src/snippets.ts
index 664bc89bdb8452..0b7838e09d1a9f 100644
--- a/packages/plugin-legacy/src/snippets.ts
+++ b/packages/plugin-legacy/src/snippets.ts
@@ -8,7 +8,7 @@ export const systemJSInlineCode = `System.import(document.getElementById('${lega
 
 const detectModernBrowserVarName = '__vite_is_modern_browser'
 export const detectModernBrowserDetector =
-  'import.meta.url;import("_").catch(()=>1);async function* g(){};'
+  'import.meta.url;import("_").catch(()=>1);(async function* g(){})();'
 export const detectModernBrowserCode = `${detectModernBrowserDetector}if(location.protocol!="file:"){window.${detectModernBrowserVarName}=true}`
 export const dynamicFallbackInlineCode = `!function(){if(window.${detectModernBrowserVarName})return;console.warn("vite: loading legacy chunks, syntax error above and the same error below should be ignored");var e=document.getElementById("${legacyPolyfillId}"),n=document.createElement("script");n.src=e.src,n.onload=function(){${systemJSInlineCode}},document.body.appendChild(n)}();`