diff --git a/lib/blockchain/chaindb.js b/lib/blockchain/chaindb.js
index 23976a824..7f075349b 100644
--- a/lib/blockchain/chaindb.js
+++ b/lib/blockchain/chaindb.js
@@ -1621,7 +1621,7 @@ class ChainDB {
    */
 
   async scanBlock(blockID, filter) {
-    assert(blockID);
+    assert(blockID != null);
 
     const entry = await this.getEntry(blockID);