diff --git a/core/ratarmountcore/SquashFSMountSource.py b/core/ratarmountcore/SquashFSMountSource.py
index 88aafe73..5b552f56 100644
--- a/core/ratarmountcore/SquashFSMountSource.py
+++ b/core/ratarmountcore/SquashFSMountSource.py
@@ -408,7 +408,7 @@ def __init__(
         **options
         # fmt: on
     ) -> None:
-        self.rawFileObject = open(fileOrPath, 'rb') if isinstance(fileOrPath, str) else fileOrPath
+        self.rawFileObject = open(fileOrPath, 'rb', 0) if isinstance(fileOrPath, str) else fileOrPath
         self.rawFileObject.seek(0)
         offset = findSquashFSOffset(self.rawFileObject)
         if offset < 0: