diff --git a/models.py b/models.py
index 652cd713..69618066 100755
--- a/models.py
+++ b/models.py
@@ -94,9 +94,11 @@ def create_modules(module_defs, img_size, arc):
                 bc = math.log(1 / (modules.nc - 0.99))  # cls bias: class probability is sigmoid(p) = 1/nc
 
                 j = l[yolo_index] if 'from' in mdef else -1
-                bias = module_list[j][0].bias.view(modules.na, -1)  # 255 to 3x85
+                bias_ = module_list[j][0].bias  # shape(255,)
+                bias = bias_[:modules.no * modules.na].view(modules.na, -1)  # shape(3,85)
                 bias[:, 4] += bo - bias[:, 4].mean()  # obj
                 bias[:, 5:] += bc - bias[:, 5:].mean()  # cls, view with utils.print_model_biases(model)
+                module_list[j][0].bias = torch.nn.Parameter(bias_, requires_grad=bias_.requires_grad)
             except:
                 print('WARNING: smart bias initialization failure.')