diff --git a/packages/app/src/App.module.css b/packages/app/src/App.module.css
index 334e9e3c6..27fb42a5d 100644
--- a/packages/app/src/App.module.css
+++ b/packages/app/src/App.module.css
@@ -148,6 +148,7 @@
 
 .error {
   composes: error from global;
+  grid-area: vis;
 }
 
 .error > span {
diff --git a/packages/app/src/providers/h5grove/__snapshots__/h5grove-api.test.ts.snap b/packages/app/src/providers/h5grove/__snapshots__/h5grove-api.test.ts.snap
index 8098df706..5cfee01cc 100644
--- a/packages/app/src/providers/h5grove/__snapshots__/h5grove-api.test.ts.snap
+++ b/packages/app/src/providers/h5grove/__snapshots__/h5grove-api.test.ts.snap
@@ -796,7 +796,11 @@ exports[`test file matches snapshot 1`] = `
       "class": "Opaque",
       "tag": "",
     },
-    "value": " "",
+    "value": Uint8Array [
+      0,
+      17,
+      34,
+    ],
   },
   {
     "name": "byte_string_1D",
@@ -813,10 +817,10 @@ exports[`test file matches snapshot 1`] = `
       "class": "Opaque",
       "tag": "",
     },
-    "value": [
-      " ",
-      "",
-      """,
+    "value": Uint8Array [
+      0,
+      17,
+      34,
     ],
   },
   {
@@ -832,7 +836,16 @@ exports[`test file matches snapshot 1`] = `
       "class": "Opaque",
       "tag": "",
     },
-    "value": [AxiosError: Request failed with status code 500],
+    "value": Uint8Array [
+      150,
+      177,
+      135,
+      93,
+      0,
+      0,
+      0,
+      0,
+    ],
   },
   {
     "name": "datetime64_not-a-time_scalar",
@@ -847,7 +860,16 @@ exports[`test file matches snapshot 1`] = `
       "class": "Opaque",
       "tag": "",
     },
-    "value": [AxiosError: Request failed with status code 500],
+    "value": Uint8Array [
+      0,
+      0,
+      0,
+      0,
+      0,
+      0,
+      0,
+      128,
+    ],
   },
   {
     "name": "complex64_scalar",
diff --git a/packages/app/src/providers/h5grove/h5grove-api.ts b/packages/app/src/providers/h5grove/h5grove-api.ts
index 5e77beebf..0e166939e 100644
--- a/packages/app/src/providers/h5grove/h5grove-api.ts
+++ b/packages/app/src/providers/h5grove/h5grove-api.ts
@@ -7,6 +7,7 @@ import type {
   ProvidedEntity,
   Value,
 } from '@h5web/shared/hdf5-models';
+import { DTypeClass } from '@h5web/shared/hdf5-models';
 import type { AxiosRequestConfig } from 'axios';
 
 import { DataProviderApi } from '../api';
@@ -45,9 +46,13 @@ export class H5GroveApi extends DataProviderApi {
   ): Promise<H5GroveDataResponse> {
     const { dataset } = params;
 
+    if (dataset.type.class === DTypeClass.Opaque) {
+      return new Uint8Array(await this.fetchBinaryData(params));
+    }
+
     const DTypedArray = h5groveTypedArrayFromDType(dataset.type);
     if (DTypedArray) {
-      const buffer = await this.fetchBinaryData(params);
+      const buffer = await this.fetchBinaryData(params, true);
       const array = new DTypedArray(buffer);
       return hasScalarShape(dataset) ? array[0] : array;
     }
@@ -149,6 +154,7 @@ export class H5GroveApi extends DataProviderApi {
 
   private async fetchBinaryData(
     params: ValuesStoreParams,
+    safe = false,
   ): Promise<ArrayBuffer> {
     const { data } = await this.cancellableFetchValue(
       '/data/',
@@ -157,7 +163,7 @@ export class H5GroveApi extends DataProviderApi {
         path: params.dataset.path,
         selection: params.selection,
         format: 'bin',
-        dtype: 'safe',
+        dtype: safe ? 'safe' : undefined,
       },
       'arraybuffer',
     );
diff --git a/packages/lib/src/vis/raw/RawVis.tsx b/packages/lib/src/vis/raw/RawVis.tsx
index 0eed23456..a00757fec 100644
--- a/packages/lib/src/vis/raw/RawVis.tsx
+++ b/packages/lib/src/vis/raw/RawVis.tsx
@@ -8,7 +8,11 @@ interface Props {
 
 function RawVis(props: Props) {
   const { value } = props;
-  const valueAsStr = JSON.stringify(value, null, 2);
+
+  const valueAsStr =
+    value instanceof Uint8Array
+      ? `Uint8Array [ ${value.toString()} ]`
+      : JSON.stringify(value, null, 2);
 
   return (
     <div className={styles.root}>
