diff --git a/packages/core/integration-tests/test/html.js b/packages/core/integration-tests/test/html.js
index d4e0fabb665..cb01766e80c 100644
--- a/packages/core/integration-tests/test/html.js
+++ b/packages/core/integration-tests/test/html.js
@@ -348,7 +348,7 @@ describe('html', function() {
     );
 
     assert(
-      /^<link rel="stylesheet" href="[/\\]index\.[a-f0-9]+\.css">\s*<script src="[/\\]index\.[a-f0-9]+\.js"><\/script>\s*<h1>Hello/m.test(
+      /^<link rel="stylesheet" href="[/\\]index\.[a-f0-9]+\.css">\s*<script src="[/\\]index\.[a-f0-9]+\.js" defer=""><\/script>\s*<h1>Hello/m.test(
         html,
       ),
     );
@@ -391,7 +391,8 @@ describe('html', function() {
     );
 
     assert.equal(
-      html.match(/<script src="[/\\]{1}index\.[a-f0-9]+?\.js">/g).length,
+      html.match(/<script src="[/\\]{1}index\.[a-f0-9]+?\.js" defer="">/g)
+        .length,
       2,
     );
   });
@@ -484,7 +485,7 @@ describe('html', function() {
     // minifySvg is false
     assert(
       html.includes(
-        '<svg version=1.1 width=300 height=200 xmlns=http://www.w3.org/2000/svg baseProfile=full><rect width=100% height=100% fill=red></rect><circle cx=150 cy=100 r=80 fill=green></circle><text x=150 y=125 font-size=60 text-anchor=middle fill=white>SVG</text></svg>',
+        '<svg version=1.1 baseprofile=full width=300 height=200 xmlns=http://www.w3.org/2000/svg><rect width=100% height=100% fill=red></rect><circle cx=150 cy=100 r=80 fill=green></circle><text x=150 y=125 font-size=60 text-anchor=middle fill=white>SVG</text></svg>',
       ),
     );
   });
@@ -790,6 +791,9 @@ describe('html', function() {
   it('should ignore svgs referencing local symbols via <use xlink:href="#">', async function() {
     let b = await bundle(
       path.join(__dirname, '/integration/html-svg-local-symbol/index.html'),
+      {
+        mode: 'production',
+      },
     );
 
     assertBundles(b, [
@@ -798,6 +802,13 @@ describe('html', function() {
         assets: ['index.html'],
       },
     ]);
+
+    let contents = await outputFS.readFile(b.getBundles()[0].filePath, 'utf8');
+    assert(
+      contents.includes(
+        '<svg><symbol id="all"><rect width="100" height="100"/></symbol></svg><svg xmlns:xlink="http://www.w3.org/1999/xlink"><use xlink:href="#all" href="#all"/></svg>',
+      ),
+    );
   });
 
   it('should bundle svg files using <image xlink:href=""> correctly', async function() {
diff --git a/packages/core/integration-tests/test/integration/html-svg-local-symbol/index.html b/packages/core/integration-tests/test/integration/html-svg-local-symbol/index.html
index a779f04b691..a5ec2e4d1aa 100644
--- a/packages/core/integration-tests/test/integration/html-svg-local-symbol/index.html
+++ b/packages/core/integration-tests/test/integration/html-svg-local-symbol/index.html
@@ -1,9 +1,9 @@
 <!DOCTYPE html>
-<svg xmlns:xlink="http://www.w3.org/1999/xlink">
-	<use xlink:href="#all" href="#all"/>
-</svg>
-<svg xmlns:xlink="http://www.w3.org/1999/xlink">
+<svg>
 	<symbol id="all">
 		<rect width="100" height="100" x="0" y="0"/>
 	</symbol>
-</svg>
\ No newline at end of file
+</svg>
+<svg>
+	<use xlink:href="#all" href="#all"/>
+</svg>
diff --git a/packages/optimizers/htmlnano/src/HTMLNanoOptimizer.js b/packages/optimizers/htmlnano/src/HTMLNanoOptimizer.js
index bbf14ccd806..79bd1fcaf20 100644
--- a/packages/optimizers/htmlnano/src/HTMLNanoOptimizer.js
+++ b/packages/optimizers/htmlnano/src/HTMLNanoOptimizer.js
@@ -83,6 +83,17 @@ export default (new Optimizer({
               keepRoleAttr: true,
             },
           },
+          // Do not minify ids or remove unreferenced elements in inline SVGs
+          // because they could actually be referenced by a separate inline SVG.
+          {
+            name: 'cleanupIDs',
+            active: false,
+          },
+          // XML namespaces are not required in HTML.
+          {
+            name: 'removeXMLNS',
+            active: true,
+          },
         ]),
       },
       ...(preset || {}),
@@ -91,10 +102,15 @@ export default (new Optimizer({
       // skipConfigLoading: true,
     };
 
+    let plugins = [htmlnano(htmlNanoConfig)];
+
+    // $FlowFixMe
+    if (htmlNanoConfig.minifySvg !== false) {
+      plugins.unshift(mapSVG);
+    }
+
     return {
-      contents: (
-        await posthtml([mapSVG, htmlnano(htmlNanoConfig)]).process(contents)
-      ).html,
+      contents: (await posthtml(plugins).process(contents)).html,
     };
   },
 }): Optimizer);
@@ -113,6 +129,23 @@ function mapSVG(
     }
   } else if (node && typeof node === 'object') {
     let {tag, attrs} = node;
+
+    // SVG in HTML does not require xml namespaces to be declared, but standalone SVG files do.
+    // If unset, add them here so that SVGO doesn't have parse errors.
+    if (tag === 'svg') {
+      if (!attrs) {
+        node.attrs = attrs = {};
+      }
+
+      if (!attrs.xmlns) {
+        attrs.xmlns = 'http://www.w3.org/2000/svg';
+      }
+
+      if (!attrs['xmlns:xlink']) {
+        attrs['xmlns:xlink'] = 'http://www.w3.org/1999/xlink';
+      }
+    }
+
     if (inSVG || tag === 'svg') {
       if (SVG_TAG_NAMES[tag]) {
         node.tag = SVG_TAG_NAMES[tag];
diff --git a/packages/transformers/html/src/dependencies.js b/packages/transformers/html/src/dependencies.js
index 154e8e2c2d9..4068c7c92b0 100644
--- a/packages/transformers/html/src/dependencies.js
+++ b/packages/transformers/html/src/dependencies.js
@@ -173,6 +173,10 @@ export default function collectDependencies(
       if (attrs.type === 'module' && asset.env.shouldScopeHoist) {
         outputFormat = 'esmodule';
       } else {
+        if (attrs.type === 'module') {
+          attrs.defer = '';
+        }
+
         delete attrs.type;
       }
 
diff --git a/packages/transformers/react-refresh-wrap/src/ReactRefreshWrapTransformer.js b/packages/transformers/react-refresh-wrap/src/ReactRefreshWrapTransformer.js
index 81cf747b909..7bd22e1cdfe 100644
--- a/packages/transformers/react-refresh-wrap/src/ReactRefreshWrapTransformer.js
+++ b/packages/transformers/react-refresh-wrap/src/ReactRefreshWrapTransformer.js
@@ -2,9 +2,6 @@
 
 import path from 'path';
 import {Transformer} from '@parcel/plugin';
-import {relativePath} from '@parcel/utils';
-
-const WRAPPER = path.join(__dirname, 'helpers', 'helpers.js');
 
 function shouldExclude(asset, options) {
   return (
@@ -26,22 +23,22 @@ export default (new Transformer({
       return [asset];
     }
 
-    let wrapperPath = relativePath(path.dirname(asset.filePath), WRAPPER);
-    if (!wrapperPath.startsWith('.')) {
-      wrapperPath = './' + wrapperPath;
-    }
+    let wrapperPath = `@parcel/transformer-react-refresh-wrap/${path.basename(
+      __dirname,
+    )}/helpers/helpers.js`;
 
     let code = await asset.getCode();
     let map = await asset.getMap();
+    let name = `$parcel$ReactRefreshHelpers$${asset.id.slice(-4)}`;
 
-    code = `var helpers = require(${JSON.stringify(wrapperPath)});
+    code = `var ${name} = require(${JSON.stringify(wrapperPath)});
 var prevRefreshReg = window.$RefreshReg$;
 var prevRefreshSig = window.$RefreshSig$;
-helpers.prelude(module);
+${name}.prelude(module);
 
 try {
 ${code}
-  helpers.postlude(module);
+  ${name}.postlude(module);
 } finally {
   window.$RefreshReg$ = prevRefreshReg;
   window.$RefreshSig$ = prevRefreshSig;
@@ -57,6 +54,7 @@ ${code}
     asset.addDependency({
       specifier: wrapperPath,
       specifierType: 'esm',
+      resolveFrom: __filename,
     });
 
     return [asset];
