diff --git a/frontend/misc/network.ts b/frontend/misc/network.ts
index d793f79..843786a 100644
--- a/frontend/misc/network.ts
+++ b/frontend/misc/network.ts
@@ -43,7 +43,7 @@ export class NetworkManager extends EventTarget {
      * Updates will be emitted as "update" events, including the download URL and the model name.
      */
     async load(url: string | Blob) {
-        if (url instanceof String && (url.startsWith("dev+") || url.startsWith("dev "))) {
+        if (!(url instanceof Blob) && (url.startsWith("dev+") || url.startsWith("dev "))) {
             let baseUrl = new URL(url.slice(4));
             baseUrl.searchParams.set("api_updates", "true");
             await this.monitorDevServer(baseUrl);