diff --git a/src/pos/root_chain.ts b/src/pos/root_chain.ts
index bee77cbd..c1848bbd 100644
--- a/src/pos/root_chain.ts
+++ b/src/pos/root_chain.ts
@@ -21,7 +21,7 @@ export class RootChain extends BaseToken<IPOSClientConfig> {
 
     getLastChildBlock() {
         return this.method("getLastChildBlock").then(method => {
-            return method.read<string>({}, this.client.config.rootChainDefaultBlock || 'safe');
+            return this.processRead<string>(method);
         });
     }