diff --git a/root/src/mappings/registry.ts b/root/src/mappings/registry.ts
index 577ae00..750e578 100644
--- a/root/src/mappings/registry.ts
+++ b/root/src/mappings/registry.ts
@@ -1,4 +1,4 @@
-import { Address } from '@graphprotocol/graph-ts'
+import { Address, Bytes } from '@graphprotocol/graph-ts'
 
 import { Registry, TokenMapped } from '../../generated/Registry/Registry'
 import { TokenMapping } from '../../generated/schema'
@@ -26,7 +26,7 @@ export function handlePlasmaTokenMapped(event: TokenMapped): void {
   // 1. keccak256('ERC721') = 0x73ad2146b3d3a286642c794379d750360a2d53a3459a11b3e5d6cc900f55f44a
   // 2. keccak256('ERC20') = 0x8ae85d849167ff996c04040c44924fd364217285e4cad818292c7ac37c0a345b
   let registry = Registry.bind(Address.fromString(registryAddress))
-  entity.tokenType = registry.isERC721(event.params.rootToken) ? '0x73ad2146b3d3a286642c794379d750360a2d53a3459a11b3e5d6cc900f55f44a' : '0x8ae85d849167ff996c04040c44924fd364217285e4cad818292c7ac37c0a345b'
+  entity.tokenType = (registry.isERC721(event.params.rootToken) ? '0x73ad2146b3d3a286642c794379d750360a2d53a3459a11b3e5d6cc900f55f44a' : '0x8ae85d849167ff996c04040c44924fd364217285e4cad818292c7ac37c0a345b') as Bytes
 
   // Yes, this is plasma mapping handler, so it's a plasma bridge token
   entity.isPOS = false