fix #397

UnityPy/environment.py

@@ -86,11 +86,24 @@ def load(self, files: List[str]):
             {ntpath.basename(f): self.load_file(self.fs.open(f, "rb"), self, f) for f in files if self.fs.exists(f)}
         )
 
-    def _load_split_file(self, basename: str) -> bytes:
+    def _load_split_file(
+        self,
+        basename: str,
+        open_f: Optional[Callable[[str], BinaryIO]] = None,
+    ) -> bytes:
         file: List[bytes] = []
-        for i in range(0, 999):
+        for i in range(0, 1000):
             item = f"{basename}.split{i}"
-            if self.fs.exists(item):
+            if open_f is not None:
+                try:
+                    f = open_f(item)
+                except (FileNotFoundError, KeyError):
+                    if i:
+                        break
+                    continue
+                with f:
+                    file.append(f.read())
+            elif self.fs.exists(item):
                 with self.fs.open(item, "rb") as f:
                     file.append(f.read())  # type: ignore
             elif i:
@@ -311,7 +324,7 @@ def load_assets(self, assets: List[str], open_f: Callable[[str], BinaryIO]):
                     continue
 
                 split_files.append(basepath)
-                data = self._load_split_file(basepath)
+                data = self._load_split_file(basepath, open_f)
                 path = basepath
             else:
                 data = open_f(path)