diff --git a/sample/generateMipmap/index.html b/sample/generateMipmap/index.html
index ca2f73b4..38a18076 100644
--- a/sample/generateMipmap/index.html
+++ b/sample/generateMipmap/index.html
@@ -11,20 +11,49 @@
       html, body {
         margin: 0;      /* remove default margin */
         height: 100%;   /* make body fill the browser window */
+        width: 100%;
         display: flex;
         place-content: center center;
       }
-      canvas {
+      #container {
+        position: relative;
         width: 600px;
         height: 600px;
         max-width: 100%;
         display: block;
       }
+      canvas, #grid {
+        width: 600px;
+        height: 600px;
+        max-width: 100%;
+        display: block;
+      }
+      #grid {
+        position: absolute;
+        left: 0;
+        top: 0;
+        display:grid;
+        grid-template-columns: 50% 50%;
+        grid-row: auto auto;
+        color: white;
+      }
+      #grid>* {
+        border: 1px solid black;
+        text-align: center;
+      }
     </style>
     <script defer src="main.js" type="module"></script>
     <script defer type="module" src="../../js/iframe-helper.js"></script>
   </head>
   <body>
-    <canvas></canvas>
+    <div id="container">
+      <canvas></canvas>
+      <div id="grid">
+        <div>2d</div>
+        <div>2d-array</div>
+        <div>cube</div>
+        <div id="cube-array">cube-array</div>
+      </div>
+    </div>
   </body>
 </html>
diff --git a/sample/generateMipmap/main.ts b/sample/generateMipmap/main.ts
index 154c0894..d2b7377a 100644
--- a/sample/generateMipmap/main.ts
+++ b/sample/generateMipmap/main.ts
@@ -72,7 +72,7 @@ const textures: {
   });
   putDataInTexture2dArray(device, texture);
   generateMips(device, texture);
-  textures.push({ texture, viewDimension: '2d' });
+  textures.push({ texture, viewDimension: '2d-array' });
 }
 
 // Make a cube texture, put an image in each face, generate mips
@@ -93,7 +93,13 @@ const textures: {
 }
 
 // Compatibility mode might not support 'core-features-and-limits'
-if (device.features.has('core-features-and-limits')) {
+// Note: Checking for maxColorAttachments > 4 is not required by the spec
+// but some browsers have not implemented 'core-features-and-limits'.
+// We'll remove this once they do.
+if (
+  device.features.has('core-features-and-limits') ||
+  device.limits.maxColorAttachments > 4
+) {
   // Make a cube array texture, put a different image in each layer, generate mips
   const texture = device.createTexture({
     size: [256, 256, 24],
@@ -122,6 +128,7 @@ if (device.features.has('core-features-and-limits')) {
   putDataInTextureCubeFallback(device, texture);
   generateMips(device, texture);
   textures.push({ texture, viewDimension: 'cube' });
+  document.querySelector('#cube-array').textContent = 'cube(fallback)';
 }
 
 const module = device.createShaderModule({
