diff --git a/configs/opensora-v1-1/train/video.py b/configs/opensora-v1-1/train/video.py
index 285ae84..7be2630 100644
--- a/configs/opensora-v1-1/train/video.py
+++ b/configs/opensora-v1-1/train/video.py
@@ -11,7 +11,7 @@ bucket_config = {  # 6s/it
     "240p": {16: (1.0, 16), 32: (1.0, 8), 64: (1.0, 4), 128: (1.0, 2)},
     "256": {1: (1.0, 256)},
     "512": {1: (1.0, 80)},
-    "480p": {1: (1.0, 52), 16: (0.5, 4), 32: (0.0, None)},
+    "480p": {1: (0.5, 52), 16: (0.5, 4), 32: (0.0, None)},
     "720p": {16: (1.0, 2), 32: (0.0, None)},  # No examples now
     "1024": {1: (1.0, 20)},
     "1080p": {1: (1.0, 8)},
diff --git a/opensora/datasets/bucket.py b/opensora/datasets/bucket.py
index f5c5b46..cf4569b 100644
--- a/opensora/datasets/bucket.py
+++ b/opensora/datasets/bucket.py
@@ -87,6 +87,7 @@ class Bucket:
         hw_id = find_approximate_hw(hw, self.hw_criteria)
         if hw_id is None:
             return None
+        hw_id_index = list(self.hw_criteria.keys()).index(hw_id)
 
         # hw drops by probablity
         while True:
@@ -96,11 +97,12 @@ class Bucket:
                 prob = self.get_prob((hw_id, T_id))
                 if torch.rand(1, generator=generator).item() < prob:
                     break
-            hw_id_index = list(self.hw_criteria.keys()).index(hw_id)
-            hw_id = list(self.hw_criteria.keys())[hw_id_index + 1]
-            if hw_id_index == len(self.hw_criteria) - 1:
+            hw_id_index += 1
+            if hw_id_index >= len(self.hw_criteria) - 1:
                 break
-        if T_id is None:
+            hw_id = list(self.hw_criteria.keys())[hw_id_index + 1]
+
+        if T_id is None or hw_id_index >= len(self.hw_criteria) - 1:
             return None
 
         # ar