diff --git a/packages/core/src/utils/set-storage.ts b/packages/core/src/utils/set-storage.ts
index 2f1315d5..635e4fdf 100644
--- a/packages/core/src/utils/set-storage.ts
+++ b/packages/core/src/utils/set-storage.ts
@@ -38,13 +38,25 @@ function objectToStorageItems(meta: DecoratedMeta, storage: StorageConfig): RawS
 
       if (storageEntry.meta.type.isPlain) {
         const key = new StorageKey(meta.registry, [storageEntry])
-        const type = storageEntry.meta.modifier.isOptional ? `Option<${key.outputType}>` : key.outputType
-        storageItems.push([key.toHex(), storage ? meta.registry.createType(type, storage).toHex() : null])
+        if (storageEntry.meta.modifier.isOptional && storage === '0x') {
+          storageItems.push([key.toHex(), '0x'])
+        } else {
+          storageItems.push([
+            key.toHex(),
+            storage ? u8aToHex(meta.registry.createType(key.outputType, storage).toU8a()) : null,
+          ])
+        }
       } else {
         for (const [keys, value] of storage) {
           const key = new StorageKey(meta.registry, [storageEntry, keys])
-          const type = storageEntry.meta.modifier.isOptional ? `Option<${key.outputType}>` : key.outputType
-          storageItems.push([key.toHex(), value ? meta.registry.createType(type, value).toHex() : null])
+          if (storageEntry.meta.modifier.isOptional && value === '0x') {
+            storageItems.push([key.toHex(), '0x'])
+          } else {
+            storageItems.push([
+              key.toHex(),
+              value ? u8aToHex(meta.registry.createType(key.outputType, value).toU8a()) : null,
+            ])
+          }
         }
       }
     }
diff --git a/packages/e2e/src/import-storage/index.test.ts b/packages/e2e/src/import-storage/index.test.ts
index baa31583..84879de7 100644
--- a/packages/e2e/src/import-storage/index.test.ts
+++ b/packages/e2e/src/import-storage/index.test.ts
@@ -2,6 +2,7 @@ import { describe, expect, it } from 'vitest'
 import path from 'path'
 
 import { api, chain, setupApi } from '../helper.js'
+import { compactHex } from '@acala-network/chopsticks'
 import { overrideStorage, overrideWasm } from '@acala-network/chopsticks/utils/override.js'
 
 setupApi({
@@ -14,12 +15,21 @@ const sudoKey = '0x5c0d1176a568c1f92944340dbfed9e9c530ebca703c85910e7164cb7d1c9e
 describe('import-storage', () => {
   it('works', async () => {
     const block = await chain.getBlock()
+    if (!block) throw new Error('block not found')
 
-    expect(await block?.get(sudoKey)).toBe('0x6d6f646c6163612f747273790000000000000000000000000000000000000000')
+    expect(await block.get(sudoKey)).toBe('0x6d6f646c6163612f747273790000000000000000000000000000000000000000')
 
     await overrideStorage(chain, path.join(__dirname, './storage.ok.yml'))
 
-    expect(await block?.get(sudoKey)).toBeUndefined()
+    expect(await block.get(sudoKey)).toBe('0x') // None
+
+    {
+      const key = compactHex((await block.meta).query.stableAsset.pools(0))
+      expect(await block.get(key)).toBe('0x') // None
+    }
+
+    const key = compactHex((await block.meta).query.timestamp.now())
+    expect(await block.get(key)).toBe('0x0100000000000000')
   })
 
   it('handle errors', async () => {
diff --git a/packages/e2e/src/import-storage/storage.ok.yml b/packages/e2e/src/import-storage/storage.ok.yml
index 71e81d87..ad5f3e38 100644
--- a/packages/e2e/src/import-storage/storage.ok.yml
+++ b/packages/e2e/src/import-storage/storage.ok.yml
@@ -1,5 +1,15 @@
 Sudo:
-  Key: null
+  Key: 0x
+
+Timestamp:
+  Now: 1
+
+StableAsset:
+  Pools:
+    -
+      -
+        - 0
+      - 0x
 
 TechnicalCommittee:
   Members: