_block.LZ4BlockError: Decompression failed (Error code: 30236)

[davispuh]

Hi,

I'm trying to extract images from UnityFS bundles but unfortunately it fails

Header is

00000000  55 6e 69 74 79 46 53 00  00 00 00 07 35 2e 78 2e  |UnityFS.....5.x.|
00000010  78 00 32 30 32 31 2e 32  2e 30 62 39 00 00 00 00  |x.2021.2.0b9....|
00000020  00 03 69 cb dd 00 00 12  5f 00 00 12 5f 00 00 00  |..i....._..._...|
00000030  c0 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

$ unityextract --images -o /tmp/ __data
Traceback (most recent call last):
  File "/usr/bin/unityextract", line 159, in <module>
    main()
  File "/usr/bin/unityextract", line 155, in main
    exit(app.run())
  File "/usr/bin/unityextract", line 54, in run
    bundle = unitypack.load(f)
  File "/usr/lib/python3.9/site-packages/unitypack/__init__.py", line 12, in load
    return env.load(file)
  File "/usr/lib/python3.9/site-packages/unitypack/environment.py", line 28, in load
    ret.load(file)
  File "/usr/lib/python3.9/site-packages/unitypack/assetbundle.py", line 49, in load
    self.load_unityfs(buf)
  File "/usr/lib/python3.9/site-packages/unitypack/assetbundle.py", line 128, in load_unityfs
    storage = ArchiveBlockStorage(blocks, buf)
  File "/usr/lib/python3.9/site-packages/unitypack/assetbundle.py", line 197, in __init__
    self._seek(0)
  File "/usr/lib/python3.9/site-packages/unitypack/assetbundle.py", line 230, in _seek
    self.seek_to_block(new_cursor)
  File "/usr/lib/python3.9/site-packages/unitypack/assetbundle.py", line 256, in seek_to_block
    self.current_stream = self.current_block.decompress(buf)
  File "/usr/lib/python3.9/site-packages/unitypack/assetbundle.py", line 181, in decompress
    res = lz4_decompress(buf.read(self.compressed_size), self.uncompressed_size)
  File "/usr/lib/python3.9/site-packages/unitypack/utils.py", line 11, in lz4_decompress
    return decompress(data, size)
_block.LZ4BlockError: Decompression failed: corrupt input or insufficient space in destination buffer. Error code: 30236

Any ideas?

[Zedragon]

I'm also having the issue _block.LZ4BlockError: Decompression failed: corrupt input or insufficient space in destination buffer. Error code: 16 ever since hearthstone update to 21.6 where they updated the unity engine. Does anyone have a solution

[sebastientromp]

I switched to UnityPy. I had to update my code, but the project is actively maintained and has an active Discord community, so it felt like a worthy investment.

[Milek7]

diff --git a/unitypack/assetbundle.py b/unitypack/assetbundle.py
index 4c5a77c..8c6f7a1 100644
--- a/unitypack/assetbundle.py
+++ b/unitypack/assetbundle.py
@@ -98,6 +98,8 @@ class AssetBundle:
                self.ciblock_size = buf.read_uint()
                self.uiblock_size = buf.read_uint()
                flags = buf.read_uint()
+               if self.format_version >= 7:
+                       buf.seek((buf.tell() + 15) // 16 * 16)
                compression = CompressionType(flags & 0x3F)
                eof_metadata = flags & 0x80
                if eof_metadata:

(note that there are other differences in asset format that it still doesn't work fully, but I was only interested in block format)

[hitfzyangdianshi]

maybe you can try to use this fork: https://github.com/CancerGary/UnityPack/tree/fix/2020.1