I'm trying to figure out how to unpack the payload data made by NSISbi for of NSIS that adds support for installer size > 2GB. Here is an example installer: https://download.unity3d.com/download_unity/068178b99f32/Windows64EditorInstaller/UnitySetup64-2020.2.2f1.exe
Here are small examples of payloads between vanilla NSIS and NSISbi: https://www.dropbox.com/sh/jn4iyppbj1v8fmf/AAAsqlymn8AHgYhSPAG9iU7Ka?dl=1
7zip used to work on NSIS and forks but it cant open this one. So far I have figured out that there is some changes in signature match:
and the payload size that comes after signature (skipping 4 bytes) is now no longer int32 but int64 (since it is a native int to have support for larger address):
Just doing these changes (removing extra
30 00 00 00 from signature and extra bytes form payload size) to payload results in 7zip being able to partially open the zlip/blip/lzma compressed data but a lot of entries are missing and some names broken.