From baaa33524b79308861d7b5c9199b6ed938ea4157 Mon Sep 17 00:00:00 2001
From: Snowyegret <79635537+snowyegret23@users.noreply.github.com>
Date: Fri, 23 Jan 2026 06:28:39 +0900
Subject: [PATCH] Fix UnityFS block info flags when saving bundles

---
 UnityPy/files/BundleFile.py | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/UnityPy/files/BundleFile.py b/UnityPy/files/BundleFile.py
index 8f6eb901..d0bb1f34 100644
--- a/UnityPy/files/BundleFile.py
+++ b/UnityPy/files/BundleFile.py
@@ -215,7 +215,7 @@ def save(self, packer=None):
             self.save_web_raw(writer)
         elif self.signature == "UnityFS":
             if not packer or packer == "none":
-                self.save_fs(writer, 64, 64)
+                self.save_fs(writer, 0x40, 0)
             elif packer == "original":
                 self.save_fs(
                     writer,
@@ -282,6 +282,9 @@ def save_fs(self, writer: EndianBinaryWriter, data_flag: int, block_info_flag: i
 
         # file list & file data
         # prep nodes and build up block data
+        data_flag = int(data_flag)
+        block_info_flag = int(block_info_flag) & 0x3F
+
         data_writer = EndianBinaryWriter()
         files = [
             (
@@ -316,7 +319,7 @@ def save_fs(self, writer: EndianBinaryWriter, data_flag: int, block_info_flag: i
             # compressed size
             block_writer.write_u_int(block_compressed_size)
             # flag
-            block_writer.write_u_short(block_flag)
+            block_writer.write_u_short(block_flag & 0x3F)
 
         # file block info
         if not data_flag & 0x40: