diff --git a/packages/types/src/Metadata/v6/latest.substrate.v6.json b/packages/types/src/Metadata/v6/latest.substrate.v6.json
index 10b91f8abf..ce4e1101b3 100644
--- a/packages/types/src/Metadata/v6/latest.substrate.v6.json
+++ b/packages/types/src/Metadata/v6/latest.substrate.v6.json
@@ -1483,7 +1483,7 @@
           "constants": [
             {
               "name": "DEDUP_KEY_PREFIX",
-              "type": "Data",
+              "type": "Bytes",
               "value": "0x343a73657373696f6e3a6b657973",
               "documentation": [
                 " Used as first key for `NextKeys` and `KeyOwner` to put all the data into the same branch",
diff --git a/packages/types/src/primitive/Type.ts b/packages/types/src/primitive/Type.ts
index fd6fef1037..8f075e23d8 100644
--- a/packages/types/src/primitive/Type.ts
+++ b/packages/types/src/primitive/Type.ts
@@ -57,8 +57,8 @@ export default class Type extends Text {
       Type._alias('Compact<Index>', 'IndexCompact'),
       // alias Vec<u8> -> Bytes
       Type._alias('Vec<u8>', 'Bytes'),
-      // alias &[u8] -> Data (this has no length-prefix)
-      Type._alias('&\\[u8\\]', 'Data'),
+      // alias &[u8] -> Bytes
+      Type._alias('&\\[u8\\]', 'Bytes'),
       // alias RawAddress -> Address
       Type._alias('RawAddress', 'Address'),
       // alias Lookup::Source to Address (_could_ be AccountId on certain chains)