diff --git a/codes/models/gpt_voice/lucidrains_gpt.py b/codes/models/gpt_voice/lucidrains_gpt.py
index 8aad83e5..1b314af2 100644
--- a/codes/models/gpt_voice/lucidrains_gpt.py
+++ b/codes/models/gpt_voice/lucidrains_gpt.py
@@ -6,9 +6,8 @@ import torch.nn.functional as F
 from einops import rearrange
 
 # helpers
-from models.arch_util import checkpoint
 from models.gpt_voice.reversible import ReversibleSequence, SequentialSequence
-from utils.util import sequential_checkpoint
+from utils.util import checkpoint
 
 
 def exists(val):
@@ -210,7 +209,7 @@ class Transformer(nn.Module):
         intermediates = []
         for attn, ff in self.layers.layers:
             x_ff = x + checkpoint(attn, x)
-            x = x + ff(x_ff)
+            x = x_ff + ff(x_ff)
             if return_intermediates:
                 intermediates.append((x_ff, x))
         if return_intermediates: