diff --git a/src/brevitas/nn/quant_conv.py b/src/brevitas/nn/quant_conv.py
index 846d4f290..5af432af7 100644
--- a/src/brevitas/nn/quant_conv.py
+++ b/src/brevitas/nn/quant_conv.py
@@ -35,7 +35,7 @@ def __init__(
             dilation: Union[int, Tuple[int, int]] = 1,
             groups: int = 1,
             padding_mode: str = 'zeros',
-            bias: bool = True,
+            bias: Optional[bool] = True,
             weight_quant: Optional[WeightQuantType] = Int8WeightPerTensorFloat,
             bias_quant: Optional[BiasQuantType] = None,
             input_quant: Optional[ActQuantType] = None,
@@ -129,7 +129,7 @@ def __init__(
             dilation: Union[int, Tuple[int, int]] = 1,
             groups: int = 1,
             padding_mode: str = 'zeros',
-            bias: bool = True,
+            bias: Optional[bool] = True,
             weight_quant: Optional[WeightQuantType] = Int8WeightPerTensorFloat,
             bias_quant: Optional[BiasQuantType] = None,
             input_quant: Optional[ActQuantType] = None,
diff --git a/src/brevitas/nn/quant_convtranspose.py b/src/brevitas/nn/quant_convtranspose.py
index c5dbd52b9..64fbe8eb6 100644
--- a/src/brevitas/nn/quant_convtranspose.py
+++ b/src/brevitas/nn/quant_convtranspose.py
@@ -38,7 +38,7 @@ def __init__(
             dilation: int = 1,
             groups: int = 1,
             padding_mode: str = 'zeros',
-            bias: bool = True,
+            bias: Optional[bool] = True,
             weight_quant: Optional[WeightQuantType] = Int8WeightPerTensorFloat,
             bias_quant: Optional[BiasQuantType] = None,
             input_quant: Optional[ActQuantType] = None,
@@ -135,7 +135,7 @@ def __init__(
             dilation: Union[int, Tuple[int]] = 1,
             groups: int = 1,
             padding_mode: str = 'zeros',
-            bias: bool = True,
+            bias: Optional[bool] = True,
             weight_quant: Optional[WeightQuantType] = Int8WeightPerTensorFloat,
             bias_quant: Optional[BiasQuantType] = None,
             input_quant: Optional[ActQuantType] = None,
diff --git a/src/brevitas/nn/quant_linear.py b/src/brevitas/nn/quant_linear.py
index 576529a32..46f3191b9 100644
--- a/src/brevitas/nn/quant_linear.py
+++ b/src/brevitas/nn/quant_linear.py
@@ -27,7 +27,7 @@ def __init__(
             self,
             in_features: int,
             out_features: int,
-            bias: bool,
+            bias: Optional[bool] = True,
             weight_quant: Optional[WeightQuantType] = Int8WeightPerTensorFloat,
             bias_quant: Optional[BiasQuantType] = None,
             input_quant: Optional[ActQuantType] = None,
diff --git a/src/brevitas/nn/quant_rnn.py b/src/brevitas/nn/quant_rnn.py
index 396a4f6ef..642c1b2d1 100644
--- a/src/brevitas/nn/quant_rnn.py
+++ b/src/brevitas/nn/quant_rnn.py
@@ -882,7 +882,7 @@ def __init__(
             hidden_size: int,
             num_layers: int = 1,
             nonlinearity: str = 'tanh',
-            bias: bool = True,
+            bias: Optional[bool] = True,
             batch_first: bool = False,
             bidirectional: bool = False,
             weight_quant=Int8WeightPerTensorFloat,
@@ -921,7 +921,7 @@ def __init__(
             input_size: int,
             hidden_size: int,
             num_layers: int = 1,
-            bias: bool = True,
+            bias: Optional[bool] = True,
             batch_first: bool = False,
             bidirectional: bool = False,
             weight_quant=Int8WeightPerTensorFloat,