diff --git a/modAionImpl/src/org/aion/zero/impl/db/AionBlockStore.java b/modAionImpl/src/org/aion/zero/impl/db/AionBlockStore.java
index bd64463d31..81623fe27e 100644
--- a/modAionImpl/src/org/aion/zero/impl/db/AionBlockStore.java
+++ b/modAionImpl/src/org/aion/zero/impl/db/AionBlockStore.java
@@ -558,9 +558,10 @@ boolean isBlockStored(byte[] hash, long number) {
     }
 
     /**
-     *  Retrieve block with unity protocol info
-     * @param hash given hash of the block
-     * @return the block data has matched hash with unity protocol info
+     * Retrieve a block with unity protocol info.
+     *
+     * @param hash the hash of the requested block
+     * @return the block data for the given hash with unity protocol info
      */
     public Block getBlockByHashWithInfo(byte[] hash) {
         if (hash == null) {
diff --git a/modAionImpl/src/org/aion/zero/impl/types/AbstractBlock.java b/modAionImpl/src/org/aion/zero/impl/types/AbstractBlock.java
index 9bff8a8c2b..c8e039685f 100644
--- a/modAionImpl/src/org/aion/zero/impl/types/AbstractBlock.java
+++ b/modAionImpl/src/org/aion/zero/impl/types/AbstractBlock.java
@@ -14,7 +14,7 @@
 public abstract class AbstractBlock implements Block {
 
     /** use for cli tooling */
-    Boolean mainChain;
+    boolean mainChain = false;
     
     // set from BlockInfos in index database
     protected BigInteger totalDifficulty;
@@ -93,7 +93,7 @@ public void setTotalDifficulty(BigInteger totalDifficulty) {
 
     @Override
     public boolean isMainChain() {
-        return mainChain == null ? true : mainChain;
+        return mainChain;
     }
 
     @Override
diff --git a/modAionImpl/src/org/aion/zero/impl/types/AionBlock.java b/modAionImpl/src/org/aion/zero/impl/types/AionBlock.java
index 8368430afb..6aed5896bc 100644
--- a/modAionImpl/src/org/aion/zero/impl/types/AionBlock.java
+++ b/modAionImpl/src/org/aion/zero/impl/types/AionBlock.java
@@ -338,9 +338,7 @@ public String toString() {
             toStringBuff.append(" total difficulty=").append(totalDifficulty).append("\n");
         }
 
-        if (mainChain != null) {
-            toStringBuff.append("  mainChain=").append(mainChain ? "yes" : "no").append("\n");
-        }
+        toStringBuff.append("  mainChain=").append(mainChain ? "yes" : "no").append("\n");
 
         if (!getTransactionsList().isEmpty()) {
             toStringBuff
diff --git a/modAionImpl/src/org/aion/zero/impl/types/StakingBlock.java b/modAionImpl/src/org/aion/zero/impl/types/StakingBlock.java
index 58fbf62a0b..eaa4d031db 100644
--- a/modAionImpl/src/org/aion/zero/impl/types/StakingBlock.java
+++ b/modAionImpl/src/org/aion/zero/impl/types/StakingBlock.java
@@ -325,9 +325,7 @@ public String toString() {
             toStringBuff.append(" total difficulty=").append(totalDifficulty).append("\n");
         }
 
-        if (mainChain != null) {
-            toStringBuff.append("  mainChain=").append(mainChain ? "yes" : "no").append("\n");
-        }
+        toStringBuff.append("  mainChain=").append(mainChain ? "yes" : "no").append("\n");
 
         if (!getTransactionsList().isEmpty()) {
             toStringBuff.append("Txs [\n");
diff --git a/modAionImpl/test/org/aion/zero/impl/db/AionBlockStoreTest.java b/modAionImpl/test/org/aion/zero/impl/db/AionBlockStoreTest.java
index 5f68f786ee..a778ce3d77 100644
--- a/modAionImpl/test/org/aion/zero/impl/db/AionBlockStoreTest.java
+++ b/modAionImpl/test/org/aion/zero/impl/db/AionBlockStoreTest.java
@@ -21,6 +21,8 @@
 import org.aion.util.TestResources;
 import org.aion.util.types.AddressUtils;
 import org.aion.zero.impl.types.AionBlock;
+import org.aion.zero.impl.types.BlockUtil;
+import org.apache.commons.lang3.RandomUtils;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
@@ -229,6 +231,62 @@ public void testGetBlocksByRange_withAscendingOrderAndIncorrectHeight() {
         assertThat(store.getBlocksByRange(first.getNumber(), last.getNumber())).isNull();
     }
 
+    @Test
+    public void testGetBlockByHashWithInfo_withNullInput() {
+        AionBlockStore store = new AionBlockStore(index, blocks, false);
+        Block block = store.getBlockByHashWithInfo(null);
+        assertThat(block).isNull();
+    }
+
+    @Test
+    public void testGetBlockByHashWithInfo_withMissingBlock() {
+        byte[] blockHash = RandomUtils.nextBytes(32);
+
+        AionBlockStore store = new AionBlockStore(index, blocks, false);
+        assertThat(index.isEmpty()).isTrue();
+        assertThat(blocks.isEmpty()).isTrue();
+
+        Block block = store.getBlockByHashWithInfo(blockHash);
+        assertThat(block).isNull();
+    }
+
+    @Test
+    public void testGetBlockByHashWithInfo() {
+        Block givenBlock = consecutiveBlocks.get(0);
+        BigInteger totalDifficulty = BigInteger.TEN;
+
+        AionBlockStore store = new AionBlockStore(index, blocks, false);
+        // does not require accurate total difficulty
+        store.saveBlock(givenBlock, totalDifficulty, true);
+
+        Block block = store.getBlockByHashWithInfo(givenBlock.getHash());
+        assertThat(block).isEqualTo(givenBlock);
+        assertThat(block.getTotalDifficulty()).isEqualTo(totalDifficulty);
+        assertThat(block.isMainChain()).isTrue();
+    }
+
+    @Test
+    public void testGetBlockByHashWithInfo_withSideChain() {
+        Block givenBlock = consecutiveBlocks.get(0);
+        BigInteger totalDifficulty = BigInteger.TWO;
+
+        BigInteger sideTotalDifficulty = BigInteger.TEN;
+        Block sideBlock = BlockUtil.newBlockFromRlp(givenBlock.getEncoded());
+        sideBlock.updateHeaderDifficulty(sideTotalDifficulty.toByteArray());
+        assertThat(givenBlock.getHash()).isNotEqualTo(sideBlock.getHash());
+        assertThat(givenBlock.getEncoded()).isNotEqualTo(sideBlock.getEncoded());
+
+        AionBlockStore store = new AionBlockStore(index, blocks, false);
+        // does not require accurate total difficulty
+        store.saveBlock(givenBlock, totalDifficulty, false);
+        store.saveBlock(sideBlock, sideTotalDifficulty, true);
+
+        Block block = store.getBlockByHashWithInfo(givenBlock.getHash());
+        assertThat(block).isEqualTo(givenBlock);
+        assertThat(block.getTotalDifficulty()).isEqualTo(totalDifficulty);
+        assertThat(block.isMainChain()).isFalse();
+    }
+
     @Test
     public void testRollback() {