diff --git a/.changeset/fresh-paws-argue.md b/.changeset/fresh-paws-argue.md
new file mode 100644
index 000000000..04d1c506e
--- /dev/null
+++ b/.changeset/fresh-paws-argue.md
@@ -0,0 +1,5 @@
+---
+"preact-cli": patch
+---
+
+Transpile generators and async functions in legacy bundles. Async functions were inadvertently transpiled to generators in 3.3.0, this transpiles them to ES5.
diff --git a/packages/cli/lib/lib/babel-config.js b/packages/cli/lib/lib/babel-config.js
index df2bb1a90..e331326f7 100644
--- a/packages/cli/lib/lib/babel-config.js
+++ b/packages/cli/lib/lib/babel-config.js
@@ -10,8 +10,7 @@ module.exports = function (env, options = {}) {
 					modules: options.modules || false,
 					targets: {
 						browsers: options.browsers,
-					},
-					exclude: ['transform-regenerator'],
+					}
 				},
 			],
 		],
diff --git a/packages/cli/lib/lib/webpack/webpack-base-config.js b/packages/cli/lib/lib/webpack/webpack-base-config.js
index 62990de94..929b75cad 100644
--- a/packages/cli/lib/lib/webpack/webpack-base-config.js
+++ b/packages/cli/lib/lib/webpack/webpack-base-config.js
@@ -86,6 +86,7 @@ module.exports = function createBaseConfig(env) {
 	const browserslistDefaults = ['> 0.25%', 'IE >= 9'];
 	const browserlistConfig = Object(browserslist.findConfig(cwd));
 	const browsers =
+		env.browserslist ||
 		(isProd ? browserlistConfig.production : browserlistConfig.development) ||
 		browserlistConfig.defaults ||
 		browserslistDefaults;
@@ -173,7 +174,7 @@ module.exports = function createBaseConfig(env) {
 
 		module: {
 			rules: [
-				{
+				(info) => ({
 					// ES2015
 					enforce: 'pre',
 					test: /\.m?[jt]sx?$/,
@@ -182,10 +183,14 @@ module.exports = function createBaseConfig(env) {
 					loader: require.resolve('babel-loader'),
 					options: Object.assign(
 						{ babelrc: false },
-						createBabelConfig(env, { browsers }),
+						createBabelConfig(env, {
+							browsers: info.compiler.name === 'InjectManifest'
+								? 'supports es6-module'
+								: browsers
+						}),
 						babelrc // intentionally overwrite our settings
 					),
-				},
+				}),
 				{
 					// LESS
 					enforce: 'pre',
diff --git a/packages/cli/lib/lib/webpack/webpack-server-config.js b/packages/cli/lib/lib/webpack/webpack-server-config.js
index dcbfa34dc..057c237b3 100644
--- a/packages/cli/lib/lib/webpack/webpack-server-config.js
+++ b/packages/cli/lib/lib/webpack/webpack-server-config.js
@@ -27,5 +27,6 @@ function serverConfig(env) {
 }
 
 module.exports = function createServerConfig(env) {
+	env = Object.assign({}, env, { browserslist: 'node >= 12' });
 	return merge(baseConfig(env), serverConfig(env));
 };