diff --git a/src/firmware/alerts/UnsupportedDfuHub.tsx b/src/firmware/alerts/UnsupportedDfuHub.tsx
new file mode 100644
index 00000000..23e4a910
--- /dev/null
+++ b/src/firmware/alerts/UnsupportedDfuHub.tsx
@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2025-2026 The Pybricks Authors
+
+import { Intent } from '@blueprintjs/core';
+import { Error } from '@blueprintjs/icons';
+import React from 'react';
+import type { CreateToast } from '../../toasterTypes';
+import { useI18n } from './i18n';
+
+const UnsupportedDfuHub: React.FunctionComponent = () => {
+    const i18n = useI18n();
+    return (
+        <>
+            <p>{i18n.translate('unsupportedDfuHub.message')}</p>
+        </>
+    );
+};
+
+export const unsupportedDfuHub: CreateToast = (onAction) => ({
+    message: <UnsupportedDfuHub />,
+    icon: <Error />,
+    intent: Intent.DANGER,
+    onDismiss: () => onAction('dismiss'),
+});
diff --git a/src/firmware/alerts/index.ts b/src/firmware/alerts/index.ts
index a6187418..1d922f91 100644
--- a/src/firmware/alerts/index.ts
+++ b/src/firmware/alerts/index.ts
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-// Copyright (c) 2022-2025 The Pybricks Authors
+// Copyright (c) 2022-2026 The Pybricks Authors
 
 import { dfuError } from './DfuError';
 import { flashProgress } from './FlashProgress';
@@ -8,6 +8,7 @@ import { noDfuInterface } from './NoDfuInterface';
 import { noWebHid } from './NoWebHid';
 import { noWebUsb } from './NoWebUsb';
 import { releaseButton } from './ReleaseButton';
+import { unsupportedDfuHub } from './UnsupportedDfuHub';
 
 export default {
     dfuError,
@@ -17,4 +18,5 @@ export default {
     noWebHid,
     noWebUsb,
     releaseButton,
+    unsupportedDfuHub,
 };
diff --git a/src/firmware/alerts/translations/en.json b/src/firmware/alerts/translations/en.json
index d43aa55d..d701b2b8 100644
--- a/src/firmware/alerts/translations/en.json
+++ b/src/firmware/alerts/translations/en.json
@@ -22,6 +22,9 @@
         "installUsbDriverButton": "Install USB Driver",
         "configureUdevRulesButton": "Configure udev rules"
     },
+    "unsupportedDfuHub": {
+        "message": "This hub has different internal electronics and requires a different firmware. Pybricks does not support this yet. We are working on it!"
+    },
     "noDfuInterface": {
         "message": "This is very unusual. The USB device did not contain the expected interface."
     },
diff --git a/src/firmware/sagas.ts b/src/firmware/sagas.ts
index 7ac4fea7..553166bf 100644
--- a/src/firmware/sagas.ts
+++ b/src/firmware/sagas.ts
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-// Copyright (c) 2020-2025 The Pybricks Authors
+// Copyright (c) 2020-2026 The Pybricks Authors
 
 import {
     FirmwareReader,
@@ -754,6 +754,15 @@ function* handleFlashUsbDfu(action: ReturnType<typeof firmwareFlashUsbDfu>): Gen
             return;
         }
 
+        if (
+            device.productId === LegoUsbProductId.SpikePrimeBootloader &&
+            device.deviceVersionMajor !== 1
+        ) {
+            yield* put(alertsShowAlert('firmware', 'unsupportedDfuHub'));
+            yield* put(firmwareDidFailToFlashUsbDfu());
+            return;
+        }
+
         const dfu = new WebDFU(
             device,
             // forceInterfacesName is needed to get the flash layout map