diff --git a/CHANGELOG.md b/CHANGELOG.md
index 370c8c9da5..e15478126a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@ Changes:
 
 - Generated TS Enum interfaces now expose the `type` (with allowed values)
 - Add Kusama 9130 upgrade block
+- Internal maintainability cleanups
 
 
 ## 6.11.1 Dec 5, 2021
diff --git a/packages/api-derive/src/accounts/flags.ts b/packages/api-derive/src/accounts/flags.ts
index a60cd8b46b..ad5c149802 100644
--- a/packages/api-derive/src/accounts/flags.ts
+++ b/packages/api-derive/src/accounts/flags.ts
@@ -40,15 +40,11 @@ function parseFlags (address: AccountId | Address | string | null | undefined, [
  */
 export function flags (instanceId: string, api: ApiInterfaceRx): (address?: AccountId | Address | string | null) => Observable<DeriveAccountFlags> {
   return memo(instanceId, (address?: AccountId | Address | string | null): Observable<DeriveAccountFlags> => {
-    const councilSection = api.query.phragmenElection
-      ? 'phragmenElection'
-      : api.query.electionsPhragmen
-        ? 'electionsPhragmen'
-        : 'elections';
+    const elections = api.query.phragmenElection || api.query.electionsPhragmen || api.query.elections;
 
     return combineLatest([
-      address && api.query[councilSection]?.members
-        ? api.query[councilSection].members<Vec<ITuple<[AccountId, Balance]>>>()
+      address && elections?.members
+        ? elections.members<Vec<ITuple<[AccountId, Balance]>>>()
         : of(undefined),
       address && api.query.council?.members
         ? api.query.council.members()
@@ -63,7 +59,7 @@ export function flags (instanceId: string, api: ApiInterfaceRx): (address?: Acco
         ? api.query.sudo.key()
         : of(undefined)
     ]).pipe(
-      map((result) => parseFlags(address, result))
+      map((r) => parseFlags(address, r))
     );
   });
 }
diff --git a/packages/api-derive/src/balances/all.ts b/packages/api-derive/src/balances/all.ts
index 4e7c415d15..9fa1dc7695 100644
--- a/packages/api-derive/src/balances/all.ts
+++ b/packages/api-derive/src/balances/all.ts
@@ -165,9 +165,7 @@ function queryCurrent (api: ApiInterfaceRx, accountId: AccountId, balanceInstanc
 
       return [
         vesting
-          ? Array.isArray(vesting)
-            ? vesting
-            : [vesting]
+          ? Array.isArray(vesting) ? vesting : [vesting]
           : null,
         lockEmpty.map((e) => e ? api.registry.createType<Vec<PalletBalancesBalanceLock>>('Vec<BalanceLock>') : locks[++offset])
       ];
diff --git a/packages/api-derive/src/bounties/bounties.ts b/packages/api-derive/src/bounties/bounties.ts
index 038e26168a..d513fd82c0 100644
--- a/packages/api-derive/src/bounties/bounties.ts
+++ b/packages/api-derive/src/bounties/bounties.ts
@@ -42,14 +42,12 @@ export function bounties (instanceId: string, api: ApiInterfaceRx): () => Observ
         ? api.query.council.proposalCount<ProposalIndex>()
         : of(0)
     ]).pipe(
-      switchMap(() =>
-        combineLatest([
-          bountyBase.bounties.keys<[BountyIndex]>(),
-          api.derive.council
-            ? api.derive.council.proposals()
-            : of([])
-        ])
-      ),
+      switchMap(() => combineLatest([
+        bountyBase.bounties.keys<[BountyIndex]>(),
+        api.derive.council
+          ? api.derive.council.proposals()
+          : of([])
+      ])),
       switchMap(([keys, proposals]): Observable<Result> => {
         const ids = keys.map(({ args: [id] }) => id);
 
diff --git a/packages/api-derive/src/democracy/dispatchQueue.ts b/packages/api-derive/src/democracy/dispatchQueue.ts
index ff6dbfe838..6faebd8f10 100644
--- a/packages/api-derive/src/democracy/dispatchQueue.ts
+++ b/packages/api-derive/src/democracy/dispatchQueue.ts
@@ -61,10 +61,8 @@ function schedulerEntries (api: ApiInterfaceRx): Observable<[BlockNumber[], (Opt
           // however we have had cases on Darwinia where the indices have moved around after an
           // upgrade, which results in invalid on-chain data
           combineLatest(blockNumbers.map((blockNumber) =>
-            api.query.scheduler.agenda(blockNumber).pipe(
-              // this does create an issue since it discards all at that block
-              catchError(() => of(null))
-            )
+            // this does create an issue since it discards all at that block
+            api.query.scheduler.agenda(blockNumber).pipe(catchError(() => of(null)))
           ))
         ])
         : of<[BlockNumber[], null[]]>([[], []]);
@@ -78,30 +76,23 @@ function queryScheduler (api: ApiInterfaceRx): Observable<DeriveDispatch[]> {
       const result: SchedulerInfo[] = [];
 
       blockNumbers.forEach((at, index): void => {
-        (agendas[index] || [])
-          .filter((opt) => opt.isSome)
-          .forEach((optScheduled): void => {
-            const scheduled = optScheduled.unwrap();
+        (agendas[index] || []).filter((o) => o.isSome).forEach((o): void => {
+          const scheduled = o.unwrap();
 
-            if (scheduled.maybeId.isSome) {
-              const id = scheduled.maybeId.unwrap().toHex();
+          if (scheduled.maybeId.isSome) {
+            const id = scheduled.maybeId.unwrap().toHex();
 
-              if (id.startsWith(DEMOCRACY_ID)) {
-                const [, index] = api.registry.createType('(u64, ReferendumIndex)', id);
-                const imageHash = scheduled.call.args[0] as Hash;
-
-                result.push({ at, imageHash, index });
-              }
-            }
-          });
+            id.startsWith(DEMOCRACY_ID) && result.push({ at, imageHash: scheduled.call.args[0] as Hash, index: api.registry.createType('(u64, ReferendumIndex)', id)[1] });
+          }
+        });
       });
 
-      return result.length
-        ? combineLatest([
-          of(result),
-          api.derive.democracy.preimages(result.map(({ imageHash }) => imageHash))
-        ])
-        : of([[], []]);
+      return combineLatest([
+        of(result),
+        result.length
+          ? api.derive.democracy.preimages(result.map(({ imageHash }) => imageHash))
+          : of([])
+      ]);
     }),
     map(([infos, images]): DeriveDispatch[] =>
       infos.map((info, index) => ({ ...info, image: images[index] }))
diff --git a/packages/api-derive/src/elections/info.ts b/packages/api-derive/src/elections/info.ts
index 25616f9c89..fd29b01360 100644
--- a/packages/api-derive/src/elections/info.ts
+++ b/packages/api-derive/src/elections/info.ts
@@ -42,6 +42,18 @@ function sortAccounts ([, balanceA]: [AccountId, Balance], [, balanceB]: [Accoun
   return balanceB.cmp(balanceA);
 }
 
+function getConstants (api: ApiInterfaceRx, elections: string | null): Partial<DeriveElectionsInfo> {
+  return elections
+    ? {
+      candidacyBond: api.consts[elections].candidacyBond as Balance,
+      desiredRunnersUp: api.consts[elections].desiredRunnersUp as u32,
+      desiredSeats: api.consts[elections].desiredMembers as u32,
+      termDuration: api.consts[elections].termDuration as BlockNumber,
+      votingBond: api.consts[elections].votingBond as Balance
+    }
+    : {};
+}
+
 function queryElections (api: ApiInterfaceRx): Observable<DeriveElectionsInfo> {
   const elections = api.query.phragmenElection
     ? 'phragmenElection'
@@ -68,17 +80,7 @@ function queryElections (api: ApiInterfaceRx): Observable<DeriveElectionsInfo> {
       ])
   ).pipe(
     map(([councilMembers, candidates, members, runnersUp]): DeriveElectionsInfo => ({
-      ...(
-        elections
-          ? {
-            candidacyBond: api.consts[elections].candidacyBond as Balance,
-            desiredRunnersUp: api.consts[elections].desiredRunnersUp as u32,
-            desiredSeats: api.consts[elections].desiredMembers as u32,
-            termDuration: api.consts[elections].termDuration as BlockNumber,
-            votingBond: api.consts[elections].votingBond as Balance
-          }
-          : {}
-      ),
+      ...getConstants(api, elections),
       candidateCount: api.registry.createType('u32', candidates.length),
       candidates: candidates.map(getCandidate),
       members: members.length
diff --git a/packages/api-derive/src/staking/query.ts b/packages/api-derive/src/staking/query.ts
index b79c6f3aef..520c491dda 100644
--- a/packages/api-derive/src/staking/query.ts
+++ b/packages/api-derive/src/staking/query.ts
@@ -29,8 +29,8 @@ function parseDetails (stashId: AccountId, controllerIdOpt: Option<AccountId> |
 
 function getLedgers (api: ApiInterfaceRx, optIds: (Option<AccountId> | null)[], { withLedger = false }: StakingQueryFlags): Observable<Option<PalletStakingStakingLedger>[]> {
   const ids = optIds
-    .filter((opt): opt is Option<AccountId> => withLedger && !!opt && opt.isSome)
-    .map((opt) => opt.unwrap());
+    .filter((o): o is Option<AccountId> => withLedger && !!o && o.isSome)
+    .map((o) => o.unwrap());
   const emptyLed = api.registry.createType<Option<PalletStakingStakingLedger>>('Option<StakingLedger>');
 
   return (
diff --git a/packages/api/src/base/Init.ts b/packages/api/src/base/Init.ts
index 021a3a48e9..e32af9b220 100644
--- a/packages/api/src/base/Init.ts
+++ b/packages/api/src/base/Init.ts
@@ -7,6 +7,7 @@ import type { ExtDef } from '@polkadot/types/extrinsic/signedExtensions/types';
 import type { ChainProperties, Hash, RuntimeVersion, RuntimeVersionPartial } from '@polkadot/types/interfaces';
 import type { Registry } from '@polkadot/types/types';
 import type { BN } from '@polkadot/util';
+import type { HexString } from '@polkadot/util/types';
 import type { ApiBase, ApiDecoration, ApiOptions, ApiTypes, DecorateMethod } from '../types';
 import type { VersionedRegistry } from './types';
 
@@ -172,7 +173,7 @@ export abstract class Init<ApiType extends ApiTypes> extends Decorate<ApiType> {
     // nothing has been found, construct new
     const registry = new TypeRegistry(blockHash);
     const metadata = new Metadata(registry,
-      await firstValueFrom(this._rpcCore.state.getMetadata.raw<string>(header.parentHash))
+      await firstValueFrom(this._rpcCore.state.getMetadata.raw<HexString>(header.parentHash))
     );
 
     this._initRegistry(registry, this._runtimeChain as Text, version, metadata);
@@ -314,7 +315,7 @@ export abstract class Init<ApiType extends ApiTypes> extends Decorate<ApiType> {
     ).subscribe();
   }
 
-  private async _metaFromChain (optMetadata?: Record<string, string>): Promise<[Hash, Metadata]> {
+  private async _metaFromChain (optMetadata?: Record<string, HexString>): Promise<[Hash, Metadata]> {
     const [genesisHash, runtimeVersion, chain, chainProps, rpcMethods, chainMetadata] = await Promise.all([
       firstValueFrom(this._rpcCore.chain.getBlockHash(0)),
       firstValueFrom(this._rpcCore.state.getRuntimeVersion()),
diff --git a/packages/api/src/checkTypes.manual.ts b/packages/api/src/checkTypes.manual.ts
index 57bfd2c051..1a3e0621eb 100644
--- a/packages/api/src/checkTypes.manual.ts
+++ b/packages/api/src/checkTypes.manual.ts
@@ -85,35 +85,6 @@ async function query (api: ApiPromise, pairs: TestKeyringMap): Promise<void> {
   const multib = await api.query.system.account.multi([pairs.alice.address, pairs.bob.address]);
 
   console.log('query types:', bar, bal, bal2, override, oldBal, multia, multib);
-
-  // check multi for unsub
-  const multiUnsub = await api.queryMulti([
-    [api.query.staking.validators],
-    [api.query.system.events]
-  ], (values): void => {
-    console.log('values', values);
-
-    multiUnsub();
-  });
-
-  // check multi , Promise result
-  const multiRes = await api.queryMulti([
-    [api.query.system.account, pairs.eve.address],
-    // older chains only
-    [api.query.system.accountNonce, pairs.eve.address]
-  ]);
-
-  console.log(multiRes);
-
-  // check multi, via at
-  const apiAt = await api.at('0x12345678');
-  const multiResAt = await apiAt.queryMulti([
-    api.query.timestamp.now,
-    [apiAt.query.staking.validators],
-    [apiAt.query.system.account, pairs.eve.address]
-  ]);
-
-  console.log(multiResAt);
 }
 
 async function queryExtra (api: ApiPromise, pairs: TestKeyringMap): Promise<void> {
@@ -165,6 +136,37 @@ async function queryExtra (api: ApiPromise, pairs: TestKeyringMap): Promise<void
   }
 }
 
+async function queryMulti (api: ApiPromise, pairs: TestKeyringMap): Promise<void> {
+  // check multi for unsub
+  const multiUnsub = await api.queryMulti([
+    [api.query.staking.validators],
+    [api.query.system.events]
+  ], (values): void => {
+    console.log('values', values);
+
+    multiUnsub();
+  });
+
+  // check multi , Promise result
+  const multiRes = await api.queryMulti([
+    [api.query.system.account, pairs.eve.address],
+    // older chains only
+    [api.query.system.accountNonce, pairs.eve.address]
+  ]);
+
+  console.log(multiRes);
+
+  // check multi, via at
+  const apiAt = await api.at('0x12345678');
+  const multiResAt = await apiAt.queryMulti([
+    api.query.timestamp.now,
+    [apiAt.query.staking.validators],
+    [apiAt.query.system.account, pairs.eve.address]
+  ]);
+
+  console.log(multiResAt);
+}
+
 async function rpc (api: ApiPromise): Promise<void> {
   // defaults
   await api.rpc.chain.subscribeNewHeads((header): void => {
@@ -270,6 +272,7 @@ async function main (): Promise<void> {
     events(api),
     query(api, pairs),
     queryExtra(api, pairs),
+    queryMulti(api, pairs),
     rpc(api),
     types(api),
     tx(api, pairs),
diff --git a/packages/api/src/promise/index.spec.ts b/packages/api/src/promise/index.spec.ts
index 75471cb10e..8feab88c51 100644
--- a/packages/api/src/promise/index.spec.ts
+++ b/packages/api/src/promise/index.spec.ts
@@ -1,6 +1,7 @@
 // Copyright 2017-2021 @polkadot/api authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
+import type { HexString } from '@polkadot/util/types';
 import type { SubmittableExtrinsic } from '../types';
 
 import { jest } from '@jest/globals';
@@ -56,7 +57,7 @@ describe('ApiPromise', (): void => {
 
   describe('initialization', (): void => {
     it('Create API instance with metadata map and makes the runtime, rpc, state & extrinsics available', async (): Promise<void> => {
-      const rpcData = await provider.send<string>('state_getMetadata', []);
+      const rpcData = await provider.send<HexString>('state_getMetadata', []);
       const genesisHash = registry.createType('Hash', await provider.send('chain_getBlockHash', [])).toHex();
       const specVersion = 0;
       const api = await ApiPromise.create({ metadata: { [`${genesisHash}-${specVersion}`]: rpcData }, provider, registry, throwOnConnect: true });
diff --git a/packages/api/src/types/index.ts b/packages/api/src/types/index.ts
index 73b84e002d..b0de37a33a 100644
--- a/packages/api/src/types/index.ts
+++ b/packages/api/src/types/index.ts
@@ -17,6 +17,7 @@ import type { Hash, RuntimeVersion } from '@polkadot/types/interfaces';
 import type { Metadata } from '@polkadot/types/metadata';
 import type { CallFunction, DefinitionRpc, DefinitionRpcSub, RegisteredTypes, Registry, RegistryError, SignatureOptions, Signer } from '@polkadot/types/types';
 import type { BN } from '@polkadot/util';
+import type { HexString } from '@polkadot/util/types';
 import type { ApiBase } from '../base';
 import type { DeriveAllSections } from '../util/decorate';
 import type { ApiTypes } from './base';
@@ -54,7 +55,7 @@ export interface ApiOptions extends RegisteredTypes {
    * @description pre-bundles is a map of 'genesis hash and runtime spec version' as key to a metadata hex string
    * if genesis hash and runtime spec version matches, then use metadata, else fetch it from chain
    */
-  metadata?: Record<string, string>;
+  metadata?: Record<string, HexString>;
   /**
    * @description Transport Provider from rpc-provider. If not specified, it will default to
    * connecting to a WsProvider connecting localhost with the default port, i.e. `ws://127.0.0.1:9944`
diff --git a/packages/typegen/src/fromChain.ts b/packages/typegen/src/fromChain.ts
index d000c6ffc5..92d5714e2e 100644
--- a/packages/typegen/src/fromChain.ts
+++ b/packages/typegen/src/fromChain.ts
@@ -1,6 +1,8 @@
 // Copyright 2017-2021 @polkadot/typegen authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
+import type { HexString } from '@polkadot/util/types';
+
 import path from 'path';
 import yargs from 'yargs';
 
@@ -11,12 +13,13 @@ import { WebSocket } from '@polkadot/x-ws';
 import { generateDefaultConsts, generateDefaultErrors, generateDefaultEvents, generateDefaultQuery, generateDefaultRpc, generateDefaultTx } from './generate';
 import { HEADER, writeFile } from './util';
 
-function generate (metaHex: string, pkg: string | undefined, output: string, isStrict?: boolean): void {
+function generate (metaHex: HexString, pkg: string | undefined, output: string, isStrict?: boolean): void {
   console.log(`Generating from metadata, ${formatNumber((metaHex.length - 2) / 2)} bytes`);
 
+  const base = path.join(process.cwd(), output);
   const extraTypes = pkg
     // eslint-disable-next-line @typescript-eslint/no-var-requires
-    ? { [pkg]: require(path.join(process.cwd(), output, 'definitions')) as Record<string, any> }
+    ? { [pkg]: require(path.join(base, 'definitions')) as Record<string, any> }
     : {};
 
   let customLookupDefinitions;
@@ -25,20 +28,20 @@ function generate (metaHex: string, pkg: string | undefined, output: string, isS
     customLookupDefinitions = {
       rpc: {},
       // eslint-disable-next-line @typescript-eslint/no-unsafe-member-access, @typescript-eslint/no-unsafe-assignment, @typescript-eslint/no-var-requires
-      types: require(path.join(process.cwd(), output, 'lookup.ts')).default
+      types: require(path.join(base, 'lookup.ts')).default
     } as Definitions;
   } catch (error) {
     console.log('No custom definitions found.');
   }
 
-  generateDefaultConsts(path.join(process.cwd(), output, 'augment-api-consts.ts'), metaHex, extraTypes, isStrict, customLookupDefinitions);
-  generateDefaultErrors(path.join(process.cwd(), output, 'augment-api-errors.ts'), metaHex, extraTypes, isStrict);
-  generateDefaultEvents(path.join(process.cwd(), output, 'augment-api-events.ts'), metaHex, extraTypes, isStrict, customLookupDefinitions);
-  generateDefaultQuery(path.join(process.cwd(), output, 'augment-api-query.ts'), metaHex, extraTypes, isStrict, customLookupDefinitions);
-  generateDefaultRpc(path.join(process.cwd(), output, 'augment-api-rpc.ts'), extraTypes);
-  generateDefaultTx(path.join(process.cwd(), output, 'augment-api-tx.ts'), metaHex, extraTypes, isStrict, customLookupDefinitions);
+  generateDefaultConsts(path.join(base, 'augment-api-consts.ts'), metaHex, extraTypes, isStrict, customLookupDefinitions);
+  generateDefaultErrors(path.join(base, 'augment-api-errors.ts'), metaHex, extraTypes, isStrict);
+  generateDefaultEvents(path.join(base, 'augment-api-events.ts'), metaHex, extraTypes, isStrict, customLookupDefinitions);
+  generateDefaultQuery(path.join(base, 'augment-api-query.ts'), metaHex, extraTypes, isStrict, customLookupDefinitions);
+  generateDefaultRpc(path.join(base, 'augment-api-rpc.ts'), extraTypes);
+  generateDefaultTx(path.join(base, 'augment-api-tx.ts'), metaHex, extraTypes, isStrict, customLookupDefinitions);
 
-  writeFile(path.join(process.cwd(), output, 'augment-api.ts'), (): string =>
+  writeFile(path.join(base, 'augment-api.ts'), (): string =>
     [
       HEADER('chain'),
       ...[
@@ -95,13 +98,13 @@ export function main (): void {
       };
 
       websocket.onmessage = (message: unknown): void => {
-        generate((JSON.parse((message as Record<string, string>).data) as Record<string, string>).result, pkg, output, isStrict);
+        generate((JSON.parse((message as Record<string, string>).data) as Record<string, HexString>).result, pkg, output, isStrict);
       };
     } catch (error) {
       process.exit(1);
     }
   } else {
     // eslint-disable-next-line @typescript-eslint/no-var-requires
-    generate((require(path.join(process.cwd(), endpoint)) as Record<string, string>).result, pkg, output, isStrict);
+    generate((require(path.join(process.cwd(), endpoint)) as Record<string, HexString>).result, pkg, output, isStrict);
   }
 }
diff --git a/packages/typegen/src/fromDefs.ts b/packages/typegen/src/fromDefs.ts
index d0ea386f55..8a55f7d578 100644
--- a/packages/typegen/src/fromDefs.ts
+++ b/packages/typegen/src/fromDefs.ts
@@ -1,6 +1,8 @@
 // Copyright 2017-2021 @polkadot/typegen authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
+import type { HexString } from '@polkadot/util/types';
+
 import path from 'path';
 import yargs from 'yargs';
 
@@ -32,7 +34,7 @@ export function main (): void {
 
   if (endpoint) {
     // eslint-disable-next-line @typescript-eslint/no-var-requires
-    const metaHex = (require(path.join(process.cwd(), endpoint)) as Record<string, string>).result;
+    const metaHex = (require(path.join(process.cwd(), endpoint)) as Record<string, HexString>).result;
 
     generateDefaultLookup(path.join(process.cwd(), input), metaHex);
   }
diff --git a/packages/typegen/src/generate/consts.ts b/packages/typegen/src/generate/consts.ts
index 8e89ca48e5..419425fd08 100644
--- a/packages/typegen/src/generate/consts.ts
+++ b/packages/typegen/src/generate/consts.ts
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 import type { Metadata } from '@polkadot/types/metadata/Metadata';
+import type { HexString } from '@polkadot/util/types';
 import type { ExtraTypes } from './types';
 
 import Handlebars from 'handlebars';
@@ -85,7 +86,7 @@ function generateForMeta (meta: Metadata, dest: string, extraTypes: ExtraTypes,
 
 // Call `generateForMeta()` with current static metadata
 /** @internal */
-export function generateDefaultConsts (dest = 'packages/api/src/augment/consts.ts', data?: string, extraTypes: ExtraTypes = {}, isStrict = false, customLookupDefinitions?: Definitions): void {
+export function generateDefaultConsts (dest = 'packages/api/src/augment/consts.ts', data?: HexString, extraTypes: ExtraTypes = {}, isStrict = false, customLookupDefinitions?: Definitions): void {
   const { metadata } = initMeta(data, extraTypes);
 
   return generateForMeta(metadata, dest, extraTypes, isStrict, customLookupDefinitions);
diff --git a/packages/typegen/src/generate/errors.ts b/packages/typegen/src/generate/errors.ts
index fdccb6a460..c88c5066b0 100644
--- a/packages/typegen/src/generate/errors.ts
+++ b/packages/typegen/src/generate/errors.ts
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 import type { Metadata } from '@polkadot/types/metadata/Metadata';
+import type { HexString } from '@polkadot/util/types';
 import type { ExtraTypes } from './types';
 
 import Handlebars from 'handlebars';
@@ -48,7 +49,7 @@ function generateForMeta (meta: Metadata, dest: string, isStrict: boolean): void
 
 // Call `generateForMeta()` with current static metadata
 /** @internal */
-export function generateDefaultErrors (dest = 'packages/api/src/augment/errors.ts', data?: string, extraTypes: ExtraTypes = {}, isStrict = false): void {
+export function generateDefaultErrors (dest = 'packages/api/src/augment/errors.ts', data?: HexString, extraTypes: ExtraTypes = {}, isStrict = false): void {
   const { metadata } = initMeta(data, extraTypes);
 
   return generateForMeta(metadata, dest, isStrict);
diff --git a/packages/typegen/src/generate/events.ts b/packages/typegen/src/generate/events.ts
index 53ab77db5b..0d91d2ea9d 100644
--- a/packages/typegen/src/generate/events.ts
+++ b/packages/typegen/src/generate/events.ts
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 import type { Metadata } from '@polkadot/types/metadata/Metadata';
+import type { HexString } from '@polkadot/util/types';
 import type { ExtraTypes } from './types';
 
 import Handlebars from 'handlebars';
@@ -77,7 +78,7 @@ function generateForMeta (meta: Metadata, dest: string, extraTypes: ExtraTypes,
 
 // Call `generateForMeta()` with current static metadata
 /** @internal */
-export function generateDefaultEvents (dest = 'packages/api/src/augment/events.ts', data?: string, extraTypes: ExtraTypes = {}, isStrict = false, customLookupDefinitions?: Definitions): void {
+export function generateDefaultEvents (dest = 'packages/api/src/augment/events.ts', data?: HexString, extraTypes: ExtraTypes = {}, isStrict = false, customLookupDefinitions?: Definitions): void {
   const { metadata } = initMeta(data, extraTypes);
 
   return generateForMeta(metadata, dest, extraTypes, isStrict, customLookupDefinitions);
diff --git a/packages/typegen/src/generate/lookup.ts b/packages/typegen/src/generate/lookup.ts
index a9c646e08f..9686faa8e3 100644
--- a/packages/typegen/src/generate/lookup.ts
+++ b/packages/typegen/src/generate/lookup.ts
@@ -4,6 +4,7 @@
 import type { PortableType, SiLookupTypeId, SiPath, SiTypeParameter } from '@polkadot/types/interfaces';
 import type { PortableRegistry } from '@polkadot/types/metadata';
 import type { TypeDef } from '@polkadot/types/types';
+import type { HexString } from '@polkadot/util/types';
 
 import Handlebars from 'handlebars';
 import path from 'path';
@@ -213,7 +214,7 @@ function generateLookupTypes (registry: Registry, filtered: [PortableType, TypeD
   writeFile(path.join(destDir, 'index.ts'), () => generateLookupIndexTmpl({ headerType: 'defs' }), true);
 }
 
-function generateLookup (destDir: string, entries: [string | undefined, string][]): void {
+function generateLookup (destDir: string, entries: [string | undefined, HexString][]): void {
   entries.reduce<string[]>((exclude, [subPath, staticMeta]): string[] => {
     const { lookup, registry } = initMeta(staticMeta).metadata.asLatest;
     const filtered = getFilteredTypes(lookup, exclude);
@@ -230,7 +231,7 @@ function generateLookup (destDir: string, entries: [string | undefined, string][
 }
 
 // Generate `packages/types/src/lookup/*s`, the registry of all lookup types
-export function generateDefaultLookup (destDir = 'packages/types/src/augment/lookup', staticData?: string): void {
+export function generateDefaultLookup (destDir = 'packages/types/src/augment/lookup', staticData?: HexString): void {
   generateLookup(
     destDir,
     staticData
diff --git a/packages/typegen/src/generate/query.ts b/packages/typegen/src/generate/query.ts
index 81b4d5aa77..fda1f51422 100644
--- a/packages/typegen/src/generate/query.ts
+++ b/packages/typegen/src/generate/query.ts
@@ -4,6 +4,7 @@
 import type { StorageEntryMetadataLatest } from '@polkadot/types/interfaces';
 import type { Metadata, PortableRegistry } from '@polkadot/types/metadata';
 import type { Definitions, Registry } from '@polkadot/types/types';
+import type { HexString } from '@polkadot/util/types';
 import type { ExtraTypes } from './types';
 
 import Handlebars from 'handlebars';
@@ -134,7 +135,7 @@ function generateForMeta (registry: Registry, meta: Metadata, dest: string, extr
 
 // Call `generateForMeta()` with current static metadata
 /** @internal */
-export function generateDefaultQuery (dest = 'packages/api/src/augment/query.ts', data?: string, extraTypes: ExtraTypes = {}, isStrict = false, customLookupDefinitions?: Definitions): void {
+export function generateDefaultQuery (dest = 'packages/api/src/augment/query.ts', data?: HexString, extraTypes: ExtraTypes = {}, isStrict = false, customLookupDefinitions?: Definitions): void {
   const { metadata, registry } = initMeta(data, extraTypes);
 
   return generateForMeta(registry, metadata, dest, extraTypes, isStrict, customLookupDefinitions);
diff --git a/packages/typegen/src/generate/tx.ts b/packages/typegen/src/generate/tx.ts
index 36282bb1ec..e9482b4285 100644
--- a/packages/typegen/src/generate/tx.ts
+++ b/packages/typegen/src/generate/tx.ts
@@ -3,6 +3,7 @@
 
 import type { Metadata } from '@polkadot/types/metadata/Metadata';
 import type { Definitions, Registry } from '@polkadot/types/types';
+import type { HexString } from '@polkadot/util/types';
 import type { ExtraTypes } from './types';
 
 import Handlebars from 'handlebars';
@@ -119,7 +120,7 @@ function generateForMeta (registry: Registry, meta: Metadata, dest: string, extr
 
 // Call `generateForMeta()` with current static metadata
 /** @internal */
-export function generateDefaultTx (dest = 'packages/api/src/augment/tx.ts', data?: string, extraTypes: ExtraTypes = {}, isStrict = false, customLookupDefinitions?: Definitions): void {
+export function generateDefaultTx (dest = 'packages/api/src/augment/tx.ts', data?: HexString, extraTypes: ExtraTypes = {}, isStrict = false, customLookupDefinitions?: Definitions): void {
   const { metadata, registry } = initMeta(data, extraTypes);
 
   return generateForMeta(registry, metadata, dest, extraTypes, isStrict, customLookupDefinitions);
diff --git a/packages/typegen/src/util/initMeta.ts b/packages/typegen/src/util/initMeta.ts
index 601ece2653..01beac3e70 100644
--- a/packages/typegen/src/util/initMeta.ts
+++ b/packages/typegen/src/util/initMeta.ts
@@ -1,6 +1,7 @@
 // Copyright 2017-2021 @polkadot/typegen authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
+import type { HexString } from '@polkadot/util/types';
 import type { ExtraTypes } from '../generate/types';
 
 import { Metadata, TypeRegistry } from '@polkadot/types';
@@ -13,7 +14,7 @@ interface Result {
   registry: TypeRegistry;
 }
 
-export function initMeta (staticMeta = staticSubstrate, extraTypes: ExtraTypes = {}): Result {
+export function initMeta (staticMeta: HexString = staticSubstrate, extraTypes: ExtraTypes = {}): Result {
   const registry = new TypeRegistry();
 
   registerDefinitions(registry, extraTypes);
diff --git a/packages/types/src/metadata/Metadata.spec.ts b/packages/types/src/metadata/Metadata.spec.ts
index fcaa7ed32e..cf362bab5f 100644
--- a/packages/types/src/metadata/Metadata.spec.ts
+++ b/packages/types/src/metadata/Metadata.spec.ts
@@ -1,6 +1,8 @@
 // Copyright 2017-2021 @polkadot/types authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
+import type { HexString } from '@polkadot/util/types';
+
 import kusama from '@polkadot/types-support/metadata/static-kusama';
 import polkadot from '@polkadot/types-support/metadata/static-polkadot';
 import substrate from '@polkadot/types-support/metadata/static-substrate';
@@ -8,7 +10,7 @@ import substrate from '@polkadot/types-support/metadata/static-substrate';
 import { TypeRegistry } from '../create';
 import { Metadata } from './Metadata';
 
-const allData: Record<string, string> = {
+const allData: Record<string, HexString> = {
   kusama,
   polkadot,
   substrate
diff --git a/packages/types/src/metadata/Metadata.ts b/packages/types/src/metadata/Metadata.ts
index 4453f06153..265807d75e 100644
--- a/packages/types/src/metadata/Metadata.ts
+++ b/packages/types/src/metadata/Metadata.ts
@@ -1,6 +1,7 @@
 // Copyright 2017-2021 @polkadot/types authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
+import type { HexString } from '@polkadot/util/types';
 import type { Registry } from '../types';
 
 import { isHex, isU8a, u8aToU8a } from '@polkadot/util';
@@ -12,42 +13,30 @@ const VERSION_IDX = 4;
 
 // magic + lowest supported version
 const EMPTY_METADATA = new Uint8Array([0x6d, 0x65, 0x74, 0x61, 9]);
-const EMPTY_U8A = new Uint8Array();
 
-function toU8a (value: Uint8Array | string = EMPTY_U8A): Uint8Array {
-  if (isHex(value)) {
-    return toU8a(u8aToU8a(value));
-  } else if (isU8a(value)) {
-    return value.length === 0
+function toU8a (value: Uint8Array | HexString): Uint8Array {
+  return isHex(value)
+    ? toU8a(u8aToU8a(value))
+    : value.length === 0
       ? EMPTY_METADATA
       : value;
-  }
-
-  throw new Error('Invalid type passed to Metadata constructor');
 }
 
-function decodeMetadata (registry: Registry, _value?: Uint8Array | string | Map<string, unknown> | Record<string, unknown>): MetadataVersioned {
-  if (isU8a(_value) || !_value || isHex(_value)) {
-    const value = toU8a(_value);
-    const version = value[VERSION_IDX];
+function decodeU8a (registry: Registry, value: Uint8Array): MetadataVersioned {
+  try {
+    return new MetadataVersioned(registry, value);
+  } catch (error) {
+    // This is an f-ing hack as a follow-up to another ugly hack
+    // https://github.com/polkadot-js/api/commit/a9211690be6b68ad6c6dad7852f1665cadcfa5b2
+    // when we fail on V9, try to re-parse it as v10... yes... HACK
+    if (value[VERSION_IDX] === 9) {
+      value[VERSION_IDX] = 10;
 
-    try {
-      return new MetadataVersioned(registry, value);
-    } catch (error) {
-      // This is an f-ing hack as a follow-up to another ugly hack
-      // https://github.com/polkadot-js/api/commit/a9211690be6b68ad6c6dad7852f1665cadcfa5b2
-      // when we fail on V9, try to re-parse it as v10... yes... HACK
-      if (version === 9) {
-        value[VERSION_IDX] = 10;
-
-        return decodeMetadata(registry, value);
-      }
-
-      throw error;
+      return decodeU8a(registry, value);
     }
-  }
 
-  return new MetadataVersioned(registry, _value);
+    throw error;
+  }
 }
 
 /**
@@ -56,7 +45,12 @@ function decodeMetadata (registry: Registry, _value?: Uint8Array | string | Map<
  * The versioned runtime metadata as a decoded structure
  */
 export class Metadata extends MetadataVersioned {
-  constructor (registry: Registry, value?: Uint8Array | string | Map<string, unknown> | Record<string, unknown>) {
-    super(registry, decodeMetadata(registry, value));
+  constructor (registry: Registry, value?: Uint8Array | HexString | Map<string, unknown> | Record<string, unknown>) {
+    super(
+      registry,
+      isU8a(value) || isHex(value)
+        ? decodeU8a(registry, toU8a(value))
+        : new MetadataVersioned(registry, value)
+    );
   }
 }
diff --git a/packages/types/src/metadata/decorate/constants/index.spec.ts b/packages/types/src/metadata/decorate/constants/index.spec.ts
index 56abc8e278..fadffd5c66 100644
--- a/packages/types/src/metadata/decorate/constants/index.spec.ts
+++ b/packages/types/src/metadata/decorate/constants/index.spec.ts
@@ -1,6 +1,7 @@
 // Copyright 2017-2021 @polkadot/types authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
+import type { HexString } from '@polkadot/util/types';
 import type { BlockNumber } from '../../../interfaces';
 import type { Constants } from '../types';
 
@@ -11,7 +12,7 @@ import { TypeRegistry } from '../../../create';
 import { Metadata } from '../../Metadata';
 import { decorateConstants } from '..';
 
-function init (meta: string): [Constants, TypeRegistry] {
+function init (meta: HexString): [Constants, TypeRegistry] {
   const registry = new TypeRegistry();
   const metadata = new Metadata(registry, meta);
 
diff --git a/packages/types/src/metadata/util/types.ts b/packages/types/src/metadata/util/types.ts
index 023c611691..32b4be51ba 100644
--- a/packages/types/src/metadata/util/types.ts
+++ b/packages/types/src/metadata/util/types.ts
@@ -1,9 +1,11 @@
 // Copyright 2017-2021 @polkadot/types authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
+import type { HexString } from '@polkadot/util/types';
+
 export interface Check {
   compare: Record<string, unknown>;
-  data: string;
+  data: HexString;
   fails?: string[];
   types?: Record<string, unknown>;
 }