diff --git a/i6_models/parts/frontend/generic_frontend.py b/i6_models/parts/frontend/generic_frontend.py
index 1e8c6a47..6757b50c 100644
--- a/i6_models/parts/frontend/generic_frontend.py
+++ b/i6_models/parts/frontend/generic_frontend.py
@@ -85,8 +85,8 @@ def check_valid(self):
 
         assert len(self.layer_ordering) == num_convs + num_pools + num_activations, "Number of total layers mismatch!"
 
-        for kernel_sizes in filter(None, [self.conv_kernel_sizes, self.pool_kernel_sizes]):
-            for kernel_size in kernel_sizes:
+        if self.conv_kernel_sizes is not None:
+            for kernel_size in self.conv_kernel_sizes:
                 assert all(k % 2 for k in kernel_size), "ConformerVGGFrontendV1 only supports odd kernel sizes"
 
     def __post__init__(self):
@@ -132,7 +132,7 @@ def __init__(self, model_cfg: GenericFrontendV1Config):
             if layer_type == FrontendLayerType.Conv2d:
                 conv_out_dim = model_cfg.conv_out_dims[conv_layer_index]
                 conv_kernel_size = model_cfg.conv_kernel_sizes[conv_layer_index]
-                conv_stride = 1 if model_cfg.conv_strides is None else model_cfg.conv_strides[conv_layer_index]
+                conv_stride = (1, 1) if model_cfg.conv_strides is None else model_cfg.conv_strides[conv_layer_index]
                 conv_padding = (
                     get_same_padding(conv_kernel_size)
                     if model_cfg.conv_paddings is None
@@ -177,7 +177,7 @@ def __init__(self, model_cfg: GenericFrontendV1Config):
                 last_feat_dim = calculate_output_dim(
                     in_dim=last_feat_dim,
                     filter_size=pool_kernel_size[1],
-                    stride=pool_stride[1] or pool_kernel_size[1],
+                    stride=(pool_stride or pool_kernel_size)[1],
                     padding=pool_padding[1],
                 )
                 pool_layer_index += 1