diff --git a/lib/Firtool/Firtool.cpp b/lib/Firtool/Firtool.cpp
index 555e5e4d9419..fda9794032d4 100644
--- a/lib/Firtool/Firtool.cpp
+++ b/lib/Firtool/Firtool.cpp
@@ -527,10 +527,9 @@ struct FirtoolCmdOptions {
                                   "release", "Compile with optimizations")),
       llvm::cl::init(firtool::FirtoolOptions::BuildModeDefault)};
 
-  llvm::cl::opt<bool> disableLayerSink{
-      "disable-layer-sink",
-      llvm::cl::desc("Disable layer sink"),
-  };
+  llvm::cl::opt<bool> disableLayerSink{"disable-layer-sink",
+                                       llvm::cl::desc("Disable layer sink"),
+                                       cl::init(false)};
 
   llvm::cl::opt<bool> disableOptimization{
       "disable-opt",
@@ -770,9 +769,10 @@ circt::firtool::FirtoolOptions::FirtoolOptions()
       allowAddingPortsOnPublic(false), probesToSignals(false),
       preserveAggregate(firrtl::PreserveAggregate::None),
       preserveMode(firrtl::PreserveValues::None), enableDebugInfo(false),
-      buildMode(BuildModeRelease), disableOptimization(false),
-      exportChiselInterface(false), chiselInterfaceOutDirectory(""),
-      vbToBV(false), noDedup(false), companionMode(firrtl::CompanionMode::Bind),
+      buildMode(BuildModeRelease), disableLayerSink(false),
+      disableOptimization(false), exportChiselInterface(false),
+      chiselInterfaceOutDirectory(""), vbToBV(false), noDedup(false),
+      companionMode(firrtl::CompanionMode::Bind),
       disableAggressiveMergeConnections(false), advancedLayerSink(false),
       lowerMemories(false), blackBoxRootPath(""), replSeqMem(false),
       replSeqMemFile(""), extractTestCode(false), ignoreReadEnableMem(false),