diff --git a/packages/types/src/Bytes.spec.ts b/packages/types/src/Bytes.spec.ts
index 4f44e00c01..d74bbc6a90 100644
--- a/packages/types/src/Bytes.spec.ts
+++ b/packages/types/src/Bytes.spec.ts
@@ -15,6 +15,12 @@ describe('Bytes', () => {
       ).toEqual(CODE);
     });
 
+    it('decodes from Array<number>', () => {
+      expect(
+        new Bytes([0x3a, 0x63, 0x6f, 0x64, 0x65]).toU8a()
+      ).toEqual(CODE);
+    });
+
     it('creates via storagedata (no prefix)', () => {
       expect(
         new Bytes(
diff --git a/packages/types/src/Bytes.ts b/packages/types/src/Bytes.ts
index b79f8ceeea..99c3bc1a3e 100644
--- a/packages/types/src/Bytes.ts
+++ b/packages/types/src/Bytes.ts
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the Apache-2.0 license. See the LICENSE file for details.
 
-import { hexToU8a, isHex, isString, isU8a, u8aToU8a } from '@polkadot/util';
+import { isString, isU8a, u8aToU8a } from '@polkadot/util';
 
 import { AnyU8a } from './types';
 import Compact from './codec/Compact';
@@ -26,10 +26,8 @@ export default class Bytes extends U8a {
     // StorageData to cater for the _specific_ problematic case
     const StorageData = require('./StorageData').default;
 
-    if (isHex(value)) {
-      // FIXME We manually add the length prefix for hex for now
-      // https://github.com/paritytech/substrate/issues/889
-      const u8a = hexToU8a(value);
+    if (Array.isArray(value) || isString(value)) {
+      const u8a = u8aToU8a(value);
 
       return Bytes.decodeBytes(
         Compact.addLengthPrefix(u8a)
@@ -51,8 +49,6 @@ export default class Bytes extends U8a {
       const [offset, length] = Compact.decodeU8a(value);
 
       return value.subarray(offset, offset + length.toNumber());
-    } else if (Array.isArray(value) || isString(value)) {
-      return Bytes.decodeBytes(u8aToU8a(value));
     }
 
     return value;
diff --git a/packages/types/src/Extrinsic.spec.ts b/packages/types/src/Extrinsic.spec.ts
index ada99676e9..bb1557312a 100644
--- a/packages/types/src/Extrinsic.spec.ts
+++ b/packages/types/src/Extrinsic.spec.ts
@@ -3,7 +3,9 @@
 // of the Apache-2.0 license. See the LICENSE file for details.
 
 import extrinsics from '@polkadot/extrinsics/static';
+import { hexToU8a, u8aToHex } from '@polkadot/util';
 
+import Compact from './codec/Compact';
 import Extrinsic from './Extrinsic';
 import Method from './Method';
 
@@ -31,4 +33,24 @@ describe('Extrinsic', () => {
     expect(extrinsic.callIndex).toEqual(new Uint8Array([2, 0]));
     expect(extrinsic.args[0].toString()).toEqual('5CPaGq4KcmntaboAxg5nyqGXdyzaBV2hj6PvhNA3syigiRg8');
   });
+
+  it('decodes an actual transaction with indexes (new format)', () => {
+    const extrinsic = new Extrinsic(
+      u8aToHex(
+        Compact.addLengthPrefix(
+          hexToU8a(
+            '0x8110f8e1ebdd3cdef7423d24fe68f3863945ea21c190907d7f3394ddf153f633c77b894af36f7a36e7ec767f4593bfd8d084b66d805605905054327a08ff6041870804270e0200ff0e6422725af0e9aede3bef6eba77bc87afadf60b9735057ae93801f4c472ad7b00407a10f35a00000000000000000000'
+          )
+        )
+      )
+    );
+
+    expect(extrinsic.isSigned).toEqual(true);
+    expect(extrinsic.signature.signer.toU8a()).toEqual(new Uint8Array([0x10]));
+    expect(extrinsic.signature.signature.toHex()).toEqual('0xf8e1ebdd3cdef7423d24fe68f3863945ea21c190907d7f3394ddf153f633c77b894af36f7a36e7ec767f4593bfd8d084b66d805605905054327a08ff60418708');
+    expect(extrinsic.signature.nonce.toNumber()).toEqual(1);
+    expect(extrinsic.signature.era.toU8a()).toEqual(new Uint8Array([0x27, 0x0e]));
+    expect(extrinsic.callIndex).toEqual(new Uint8Array([2, 0]));
+    expect(extrinsic.args[0].toString()).toEqual('5CPaGq4KcmntaboAxg5nyqGXdyzaBV2hj6PvhNA3syigiRg8');
+  });
 });
diff --git a/packages/types/src/Extrinsic.ts b/packages/types/src/Extrinsic.ts
index 7e20672272..14c2f9426e 100644
--- a/packages/types/src/Extrinsic.ts
+++ b/packages/types/src/Extrinsic.ts
@@ -5,7 +5,7 @@
 import { KeyringPair } from '@polkadot/keyring/types';
 import { AnyNumber, AnyU8a, Codec } from './types';
 
-import { hexToU8a, isHex, isU8a, u8aToHex } from '@polkadot/util';
+import { isHex, isU8a, u8aToHex, u8aToU8a } from '@polkadot/util';
 import { blake2AsU8a } from '@polkadot/util-crypto';
 
 import Compact from './codec/Compact';
@@ -42,15 +42,20 @@ export default class Extrinsic extends Struct {
   }
 
   static decodeExtrinsic (value: ExtrinsicValue | AnyU8a | Method): ExtrinsicValue | Array<number> | Uint8Array {
-    if (isHex(value)) {
-      // FIXME We manually add the length prefix for hex for now
-      // https://github.com/paritytech/substrate/issues/889
+    if (Array.isArray(value) || isHex(value)) {
       // Instead of the block below, it should simply be:
       // return Extrinsic.decodeExtrinsic(hexToU8a(value as string));
-      const u8a = hexToU8a(value);
+      const u8a = u8aToU8a(value);
+
+      // HACK 11 Jan 2019 - before https://github.com/paritytech/substrate/pull/1388
+      // extrinsics didn't have the length, cater for both approaches
+      const [offset, length] = Compact.decodeU8a(u8a);
+      const withPrefix = u8a.length === (offset + length.toNumber());
 
       return Extrinsic.decodeExtrinsic(
-        Compact.addLengthPrefix(u8a)
+        withPrefix
+          ? u8a
+          : Compact.addLengthPrefix(u8a)
       );
     } else if (isU8a(value)) {
       const [offset, length] = Compact.decodeU8a(value);