diff --git a/ultralytics/__init__.py b/ultralytics/__init__.py
index 9c24e00c..0d72f48e 100644
--- a/ultralytics/__init__.py
+++ b/ultralytics/__init__.py
@@ -1,6 +1,6 @@
 # Ultralytics YOLO 🚀, AGPL-3.0 license
 
-__version__ = "8.1.18"
+__version__ = "8.1.19"
 
 from ultralytics.data.explorer.explorer import Explorer
 from ultralytics.models import RTDETR, SAM, YOLO, YOLOWorld
diff --git a/ultralytics/data/utils.py b/ultralytics/data/utils.py
index be331bf3..1ce8127a 100644
--- a/ultralytics/data/utils.py
+++ b/ultralytics/data/utils.py
@@ -365,6 +365,9 @@ def check_cls_dataset(dataset, split=""):
     # Download (optional if dataset=https://file.zip is passed directly)
     if str(dataset).startswith(("http:/", "https:/")):
         dataset = safe_download(dataset, dir=DATASETS_DIR, unzip=True, delete=False)
+    elif Path(dataset).suffix in (".zip", ".tar", ".gz"):
+        file = check_file(dataset)
+        dataset = safe_download(file, dir=DATASETS_DIR, unzip=True, delete=False)
 
     dataset = Path(dataset)
     data_dir = (dataset if dataset.is_dir() else (DATASETS_DIR / dataset)).resolve()
diff --git a/ultralytics/engine/exporter.py b/ultralytics/engine/exporter.py
index 68892958..75f7a0f9 100644
--- a/ultralytics/engine/exporter.py
+++ b/ultralytics/engine/exporter.py
@@ -514,12 +514,12 @@ class Exporter:
                 "https://github.com/pnnx/pnnx/.\nNote PNNX Binary file must be placed in current working directory "
                 f"or in {ROOT}. See PNNX repo for full installation instructions."
             )
-            system = ["macos"] if MACOS else ["windows"] if WINDOWS else ["ubuntu", "linux"]  # operating system
+            system = "macos" if MACOS else "windows" if WINDOWS else "linux-aarch64" if ARM64 else "linux"
             try:
                 _, assets = get_github_assets(repo="pnnx/pnnx", retry=True)
-                url = [x for x in assets if any(s in x for s in system)][0]
+                url = [x for x in assets if f"{system}.zip" in x][0]
             except Exception as e:
-                url = f"https://github.com/pnnx/pnnx/releases/download/20231127/pnnx-20231127-{system[0]}.zip"
+                url = f"https://github.com/pnnx/pnnx/releases/download/20240226/pnnx-20240226-{system}.zip"
                 LOGGER.warning(f"{prefix} WARNING ⚠️ PNNX GitHub assets not found: {e}, using default {url}")
             asset = attempt_download_asset(url, repo="pnnx/pnnx", release="latest")
             if check_is_path_safe(Path.cwd(), asset):  # avoid path traversal security vulnerability
diff --git a/ultralytics/utils/ops.py b/ultralytics/utils/ops.py
index 4a835160..fb346a96 100644
--- a/ultralytics/utils/ops.py
+++ b/ultralytics/utils/ops.py
@@ -638,7 +638,7 @@ def crop_mask(masks, boxes):
     Returns:
         (torch.Tensor): The masks are being cropped to the bounding box.
     """
-    n, h, w = masks.shape
+    _, h, w = masks.shape
     x1, y1, x2, y2 = torch.chunk(boxes[:, :, None], 4, 1)  # x1 shape(n,1,1)
     r = torch.arange(w, device=masks.device, dtype=x1.dtype)[None, None, :]  # rows shape(1,1,w)
     c = torch.arange(h, device=masks.device, dtype=x1.dtype)[None, :, None]  # cols shape(1,h,1)
@@ -686,12 +686,14 @@ def process_mask(protos, masks_in, bboxes, shape, upsample=False):
     c, mh, mw = protos.shape  # CHW
     ih, iw = shape
     masks = (masks_in @ protos.float().view(c, -1)).sigmoid().view(-1, mh, mw)  # CHW
+    width_ratio = mw / iw
+    height_ratio = mh / ih
 
     downsampled_bboxes = bboxes.clone()
-    downsampled_bboxes[:, 0] *= mw / iw
-    downsampled_bboxes[:, 2] *= mw / iw
-    downsampled_bboxes[:, 3] *= mh / ih
-    downsampled_bboxes[:, 1] *= mh / ih
+    downsampled_bboxes[:, 0] *= width_ratio
+    downsampled_bboxes[:, 2] *= width_ratio
+    downsampled_bboxes[:, 3] *= height_ratio
+    downsampled_bboxes[:, 1] *= height_ratio
 
     masks = crop_mask(masks, downsampled_bboxes)  # CHW
     if upsample: