diff --git a/CHANGELOG.md b/CHANGELOG.md
index 10fdcf1f14..cb323aaee6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,7 +4,8 @@
 
 Changes:
 
-- De-alias XCmOutcome (used in multiple pallettes)
+- De-alias xcm `Outcome` (used in multiple pallettes)
+- Fix generate of well-known storage keys (e.g. `:code`)
 
 
 ## 4.7.2 Apr 26, 2021
diff --git a/packages/metadata/src/decorate/constants/index.spec.ts b/packages/metadata/src/decorate/constants/index.spec.ts
index d60fb2e1ad..332bf57ab2 100644
--- a/packages/metadata/src/decorate/constants/index.spec.ts
+++ b/packages/metadata/src/decorate/constants/index.spec.ts
@@ -17,7 +17,7 @@ function init (meta: string): [Constants, TypeRegistry] {
 
   registry.setMetadata(metadata);
 
-  return [decorateConstants(registry, metadata.asLatest), registry];
+  return [decorateConstants(registry, metadata.asLatest, 12), registry];
 }
 
 describe('decorateConstants', (): void => {
diff --git a/packages/metadata/src/decorate/constants/index.ts b/packages/metadata/src/decorate/constants/index.ts
index 69ce8549b0..b0723b46d6 100644
--- a/packages/metadata/src/decorate/constants/index.ts
+++ b/packages/metadata/src/decorate/constants/index.ts
@@ -8,7 +8,8 @@ import type { ConstantCodec, Constants, ModuleConstants } from '../types';
 import { hexToU8a, stringCamelCase } from '@polkadot/util';
 
 /** @internal */
-export function decorateConstants (registry: Registry, { modules }: MetadataLatest): Constants {
+// eslint-disable-next-line @typescript-eslint/no-unused-vars
+export function decorateConstants (registry: Registry, { modules }: MetadataLatest, _metaVersion: number): Constants {
   return modules.reduce((result: Constants, { constants, name }): Constants => {
     if (constants.isEmpty) {
       return result;
diff --git a/packages/metadata/src/decorate/index.spec.ts b/packages/metadata/src/decorate/index.spec.ts
index 4b0243b48d..580335e299 100644
--- a/packages/metadata/src/decorate/index.spec.ts
+++ b/packages/metadata/src/decorate/index.spec.ts
@@ -46,7 +46,7 @@ describe('Decorated', () => {
   });
 
   it('should return constants with the correct type and value', (): void => {
-    const consts = decorateConstants(registry, metadata.asLatest);
+    const consts = decorateConstants(registry, metadata.asLatest, metadata.version);
 
     expect(consts.democracy.cooloffPeriod).toBeInstanceOf(registry.createClass('BlockNumber'));
     expect(consts.democracy.cooloffPeriod.toHex()).toEqual('0x000c4e00');
diff --git a/packages/metadata/src/decorate/index.ts b/packages/metadata/src/decorate/index.ts
index f6e081edc1..df743ba7c9 100644
--- a/packages/metadata/src/decorate/index.ts
+++ b/packages/metadata/src/decorate/index.ts
@@ -20,13 +20,14 @@ export function expandMetadata (registry: Registry, metadata: Metadata): Decorat
   assert(metadata instanceof Metadata, 'You need to pass a valid Metadata instance to Decorated');
 
   const latest = metadata.asLatest;
+  const version = metadata.version;
 
   return {
-    consts: decorateConstants(registry, latest),
-    errors: decorateErrors(registry, latest, metadata.version),
-    events: decorateEvents(registry, latest, metadata.version),
-    query: decorateStorage(registry, latest, metadata.version),
-    tx: decorateExtrinsics(registry, latest, metadata.version)
+    consts: decorateConstants(registry, latest, version),
+    errors: decorateErrors(registry, latest, version),
+    events: decorateEvents(registry, latest, version),
+    query: decorateStorage(registry, latest, version),
+    tx: decorateExtrinsics(registry, latest, version)
   };
 }
 
diff --git a/packages/metadata/src/decorate/storage/createFunction.spec.ts b/packages/metadata/src/decorate/storage/createFunction.spec.ts
index 904e72ab02..b0c1c2f44f 100644
--- a/packages/metadata/src/decorate/storage/createFunction.spec.ts
+++ b/packages/metadata/src/decorate/storage/createFunction.spec.ts
@@ -28,7 +28,7 @@ describe('createFunction', (): void => {
       method: 'NextKeys',
       prefix: 'Session',
       section: 'session'
-    }, { metaVersion: 9 });
+    }, {});
 
     expect(
       u8aToHex(
diff --git a/packages/metadata/src/decorate/storage/createFunction.ts b/packages/metadata/src/decorate/storage/createFunction.ts
index 142fb5c8f2..8ff36fa758 100644
--- a/packages/metadata/src/decorate/storage/createFunction.ts
+++ b/packages/metadata/src/decorate/storage/createFunction.ts
@@ -9,15 +9,14 @@ import BN from 'bn.js';
 
 import { Raw } from '@polkadot/types/codec';
 import { StorageKey } from '@polkadot/types/primitive';
-import { assert, compactAddLength, compactStripLength, isNull, isUndefined, stringLowerFirst, u8aConcat } from '@polkadot/util';
+import { assert, compactAddLength, compactStripLength, isNull, isUndefined, stringLowerFirst, u8aConcat, u8aToU8a } from '@polkadot/util';
 import { xxhashAsU8a } from '@polkadot/util-crypto';
 
 import { getHasher, HasherFunction } from './getHasher';
 
 export interface CreateItemOptions {
   key?: string;
-  metaVersion: number;
-  skipHashing?: boolean; // We don't hash the keys defined in ./substrate.ts
+  skipHashing?: boolean;
 }
 
 export interface CreateItemFn {
@@ -35,7 +34,6 @@ interface IterFn {
 type CreateArgType = boolean | string | number | null | BN | BigInt | Uint8Array | Codec;
 
 const EMPTY_U8A = new Uint8Array([]);
-const NULL_HASHER = (value: Uint8Array): Uint8Array => value;
 
 // get the hashers, the base (and  in the case of DoubleMap), the second key
 /** @internal */
@@ -186,7 +184,9 @@ export function createFunction (registry: Registry, itemFn: CreateItemFn, option
   const storageFn = expandWithMeta(itemFn, (arg?: CreateArgType | [CreateArgType?, CreateArgType?]): Uint8Array =>
     type.isDoubleMap
       ? createKeyDoubleMap(registry, itemFn, arg as [CreateArgType, CreateArgType], [hasher, key2Hasher])
-      : createKey(registry, itemFn, arg as CreateArgType, options.skipHashing ? NULL_HASHER : hasher)
+      : options.skipHashing
+        ? compactAddLength(u8aToU8a(options.key))
+        : createKey(registry, itemFn, arg as CreateArgType, hasher)
   );
 
   if (type.isMap || type.isDoubleMap) {
diff --git a/packages/metadata/src/decorate/storage/getStorage.spec.ts b/packages/metadata/src/decorate/storage/getStorage.spec.ts
index dbf48ef10b..910e7825f2 100644
--- a/packages/metadata/src/decorate/storage/getStorage.spec.ts
+++ b/packages/metadata/src/decorate/storage/getStorage.spec.ts
@@ -2,19 +2,21 @@
 // SPDX-License-Identifier: Apache-2.0
 
 import { TypeRegistry } from '@polkadot/types/create';
+import { compactAddLength, u8aToU8a } from '@polkadot/util';
 
 import { getStorage } from './getStorage';
 
 describe('getSorage', (): void => {
   const registry = new TypeRegistry();
-  const storage = getStorage(registry, 8);
+  const storage = getStorage(registry);
 
   it('should return well known keys', (): void => {
     expect(typeof storage.substrate).toBe('object');
 
+    expect(storage.substrate.code()).toEqual(compactAddLength(u8aToU8a(':code')));
+
     expect(storage.substrate.changesTrieConfig).toBeTruthy();
     expect(storage.substrate.childStorageKeyPrefix).toBeTruthy();
-    expect(storage.substrate.code).toBeTruthy();
     expect(storage.substrate.extrinsicIndex).toBeTruthy();
     expect(storage.substrate.heapPages).toBeTruthy();
   });
diff --git a/packages/metadata/src/decorate/storage/getStorage.ts b/packages/metadata/src/decorate/storage/getStorage.ts
index a78a7273bf..cbb321b904 100644
--- a/packages/metadata/src/decorate/storage/getStorage.ts
+++ b/packages/metadata/src/decorate/storage/getStorage.ts
@@ -8,12 +8,12 @@ import type { Storage } from '../types';
 import { substrate } from './substrate';
 
 /** @internal */
-export function getStorage (registry: Registry, metaVersion: number): Storage {
+export function getStorage (registry: Registry): Storage {
   return {
     substrate: Object
       .entries(substrate)
       .reduce((storage: Record<string, StorageEntry>, [key, fn]): Record<string, StorageEntry> => {
-        (storage as Record<string, unknown>)[key] = fn(registry, metaVersion);
+        (storage as Record<string, unknown>)[key] = fn(registry);
 
         return storage;
       }, {})
diff --git a/packages/metadata/src/decorate/storage/index.ts b/packages/metadata/src/decorate/storage/index.ts
index 229baeae4c..4130932ac9 100644
--- a/packages/metadata/src/decorate/storage/index.ts
+++ b/packages/metadata/src/decorate/storage/index.ts
@@ -11,7 +11,8 @@ import { createFunction } from './createFunction';
 import { getStorage } from './getStorage';
 
 /** @internal */
-export function decorateStorage (registry: Registry, { modules }: MetadataLatest, metaVersion: number): Storage {
+// eslint-disable-next-line @typescript-eslint/no-unused-vars
+export function decorateStorage (registry: Registry, { modules }: MetadataLatest, _metaVersion: number): Storage {
   return modules.reduce((result: Storage, moduleMetadata): Storage => {
     if (moduleMetadata.storage.isNone) {
       return result;
@@ -31,11 +32,11 @@ export function decorateStorage (registry: Registry, { modules }: MetadataLatest
         method,
         prefix,
         section
-      }, { metaVersion });
+      }, {});
 
       return newModule;
     }, {} as ModuleStorage);
 
     return result;
-  }, { ...getStorage(registry, metaVersion) });
+  }, { ...getStorage(registry) });
 }
diff --git a/packages/metadata/src/decorate/storage/substrate.spec.ts b/packages/metadata/src/decorate/storage/substrate.spec.ts
new file mode 100644
index 0000000000..8a7e6c8cbe
--- /dev/null
+++ b/packages/metadata/src/decorate/storage/substrate.spec.ts
@@ -0,0 +1,19 @@
+// Copyright 2017-2021 @polkadot/metadata authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+import { TypeRegistry } from '@polkadot/types/create';
+import { compactAddLength, u8aToU8a } from '@polkadot/util';
+
+import { substrate } from './substrate';
+
+const registry = new TypeRegistry();
+
+describe('substrate', (): void => {
+  it('creates a well-known :code key', (): void => {
+    expect(
+      substrate.code(registry)()
+    ).toEqual(
+      compactAddLength(u8aToU8a(':code'))
+    );
+  });
+});
diff --git a/packages/metadata/src/decorate/storage/substrate.ts b/packages/metadata/src/decorate/storage/substrate.ts
index 70e07a105e..7e43edf7a0 100644
--- a/packages/metadata/src/decorate/storage/substrate.ts
+++ b/packages/metadata/src/decorate/storage/substrate.ts
@@ -12,12 +12,12 @@ interface SubstrateMetadata {
   type: string;
 }
 
-type Creator = (registry: Registry, metaVersion: number) => StorageEntry;
+type Creator = (registry: Registry) => StorageEntry;
 
 // Small helper function to factorize code on this page.
 /** @internal */
-function createRuntimeFunction (method: string, key: string, { documentation, type }: SubstrateMetadata): (registry: Registry, metaVersion: number) => StorageEntry {
-  return (registry: Registry, metaVersion: number): StorageEntry =>
+function createRuntimeFunction (method: string, key: string, { documentation, type }: SubstrateMetadata): (registry: Registry) => StorageEntry {
+  return (registry: Registry): StorageEntry =>
     createFunction(registry, {
       meta: {
         documentation: registry.createType('Vec<Text>', [documentation]),
@@ -28,7 +28,7 @@ function createRuntimeFunction (method: string, key: string, { documentation, ty
       method,
       prefix: 'Substrate',
       section: 'substrate'
-    }, { key, metaVersion, skipHashing: true });
+    }, { key, skipHashing: true });
 }
 
 export const substrate: Record<string, Creator> = {
diff --git a/packages/typegen/src/metadataMd.ts b/packages/typegen/src/metadataMd.ts
index 1b739846f8..dfe78a5a7a 100644
--- a/packages/typegen/src/metadataMd.ts
+++ b/packages/typegen/src/metadataMd.ts
@@ -195,7 +195,7 @@ function addConstants (metadata: MetadataLatest): string {
 
 /** @internal */
 function addStorage (metadata: MetadataLatest): string {
-  const { substrate } = getSubstrateStorage(metadata.registry, 12);
+  const { substrate } = getSubstrateStorage(metadata.registry);
   const moduleSections = metadata.modules
     .sort(sortByName)
     .filter((moduleMetadata) => !moduleMetadata.storage.isNone)
diff --git a/packages/types/src/create/registry.ts b/packages/types/src/create/registry.ts
index a23666c0c7..3e7c1ee35c 100644
--- a/packages/types/src/create/registry.ts
+++ b/packages/types/src/create/registry.ts
@@ -97,7 +97,7 @@ function injectExtrinsics (registry: Registry, metadata: Metadata, metadataCalls
 // extract additional properties from the metadata
 function extractProperties (registry: Registry, metadata: Metadata): ChainProperties | undefined {
   const original = registry.getChainProperties();
-  const constants = decorateConstants(registry, metadata.asLatest);
+  const constants = decorateConstants(registry, metadata.asLatest, metadata.version);
   const ss58Format = constants.system?.ss58Prefix;
 
   if (!ss58Format) {