diff --git a/packages/extension-base/src/background/handlers/Extension.ts b/packages/extension-base/src/background/handlers/Extension.ts
index c415e12..c2adca2 100644
--- a/packages/extension-base/src/background/handlers/Extension.ts
+++ b/packages/extension-base/src/background/handlers/Extension.ts
@@ -325,7 +325,8 @@ export default class Extension {
   }
 
   private seedCreate ({ length = SEED_DEFAULT_LENGTH, seed: _seed, type }: RequestSeedCreate): ResponseSeedCreate {
-    const seed = _seed || mnemonicGenerate(length);
+    // Use onlyJs=true because wasm-crypto doesn't implement bip39Generate
+    const seed = _seed || mnemonicGenerate(length, undefined, true);
 
     return {
       address: keyring.createFromUri(getSuri(seed, type), {}, type).address,
diff --git a/packages/extension/src/background.ts b/packages/extension/src/background.ts
index 4d70b88..493543f 100644
--- a/packages/extension/src/background.ts
+++ b/packages/extension/src/background.ts
@@ -29,6 +29,10 @@ function initializeExtension (): Promise<void> {
         console.log('crypto initialized');
         keyring.loadAll({ store: new AccountsStore(), type: 'sr25519' });
         console.log('initialization completed');
+      })
+      .catch((error): void => {
+        console.error('initialization failed', error);
+        throw error;
       });
   }