diff --git a/besu/src/main/java/org/hyperledger/besu/cli/BesuCommand.java b/besu/src/main/java/org/hyperledger/besu/cli/BesuCommand.java
index 7f539e33ff1..cccc5c4af7d 100644
--- a/besu/src/main/java/org/hyperledger/besu/cli/BesuCommand.java
+++ b/besu/src/main/java/org/hyperledger/besu/cli/BesuCommand.java
@@ -2005,13 +2005,13 @@ private void issueOptionWarnings() {
     CommandLineUtils.failIfOptionDoesntMeetRequirement(
         commandLine,
         "--fast-sync-min-peers can't be used with FULL sync-mode",
-        !SyncMode.isFullSync(getDefaultSyncModeIfNotSet(syncMode)),
+        !SyncMode.isFullSync(getDefaultSyncModeIfNotSet()),
         singletonList("--fast-sync-min-peers"));
 
     CommandLineUtils.failIfOptionDoesntMeetRequirement(
         commandLine,
         "--Xcheckpoint-post-merge-enabled can only be used with X_CHECKPOINT sync-mode",
-        SyncMode.X_CHECKPOINT.equals(getDefaultSyncModeIfNotSet(syncMode)),
+        SyncMode.X_CHECKPOINT.equals(getDefaultSyncModeIfNotSet()),
         singletonList("--Xcheckpoint-post-merge-enabled"));
 
     if (!securityModuleName.equals(DEFAULT_SECURITY_MODULE)
@@ -2033,7 +2033,7 @@ private void issueOptionWarnings() {
   private void configure() throws Exception {
     checkPortClash();
     checkIfRequiredPortsAreAvailable();
-    syncMode = getDefaultSyncModeIfNotSet(syncMode);
+    syncMode = getDefaultSyncModeIfNotSet();
 
     ethNetworkConfig = updateNetworkConfig(network);
 
@@ -2167,7 +2167,8 @@ public BesuController buildController() {
   public BesuControllerBuilder getControllerBuilder() {
     final KeyValueStorageProvider storageProvider = keyValueStorageProvider(keyValueStorageName);
     return controllerBuilderFactory
-        .fromEthNetworkConfig(updateNetworkConfig(network), genesisConfigOverrides, syncMode)
+        .fromEthNetworkConfig(
+            updateNetworkConfig(network), genesisConfigOverrides, getDefaultSyncModeIfNotSet())
         .synchronizerConfiguration(buildSyncConfig())
         .ethProtocolConfiguration(unstableEthProtocolOptions.toDomainObject())
         .dataDirectory(dataDir())
@@ -3436,7 +3437,7 @@ public static List<String> getJDKEnabledProtocols() {
     }
   }
 
-  private SyncMode getDefaultSyncModeIfNotSet(final SyncMode syncMode) {
+  private SyncMode getDefaultSyncModeIfNotSet() {
     return Optional.ofNullable(syncMode)
         .orElse(
             genesisFile == null
diff --git a/besu/src/test/java/org/hyperledger/besu/cli/subcommands/blocks/BlocksSubCommandTest.java b/besu/src/test/java/org/hyperledger/besu/cli/subcommands/blocks/BlocksSubCommandTest.java
index b6421b84ad2..6a0b5592d27 100644
--- a/besu/src/test/java/org/hyperledger/besu/cli/subcommands/blocks/BlocksSubCommandTest.java
+++ b/besu/src/test/java/org/hyperledger/besu/cli/subcommands/blocks/BlocksSubCommandTest.java
@@ -19,6 +19,7 @@
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyBoolean;
 import static org.mockito.ArgumentMatchers.anyLong;
+import static org.mockito.ArgumentMatchers.isNotNull;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
@@ -487,4 +488,13 @@ private void createDbDirectory(final boolean createDataFiles) throws IOException
       assertThat(success).isTrue();
     }
   }
+
+  @Test
+  public void blocksImportWithNoSyncModeDoesNotRaiseNPE() throws IOException {
+    final File fileToImport = temp.newFile("blocks.file");
+    parseCommand(
+        BLOCK_SUBCOMMAND_NAME, BLOCK_IMPORT_SUBCOMMAND_NAME, "--from", fileToImport.getPath());
+
+    verify(mockControllerBuilderFactory).fromEthNetworkConfig(any(), any(), isNotNull());
+  }
 }