Support lzraven compression / pbzm payload files

[Wack0]

Is your feature request related to a problem? Please describe.

macOS 27.0 beta 1's OTA update files use payload files with the magic pbzm, reversing UpdateBrainLibrary.dylib shows this is using lzraven compression, which according to documentation was added in this version of the OS: https://developer.apple.com/documentation/compression/compression_lzraven

Describe the solution you'd like

• Reverse and reimplement the lzraven compression scheme
• Support this compression scheme when extracting payload files.

Describe alternatives you've considered

• Reversing lzraven myself (reversing heavily vectorised compression code is not my idea of a fun time)
• Emulating the decompression code under unicorn
• Running the decompressor in an OSX vm

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• I did search for other open and closed issues before opening this

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Additional context

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[blacktop]

Fix is darwin OS only (for now) the CI will kick out a pre-release; please try and see if it works for you.

[Wack0]

I don't have any ARM64 Mac to test with, however 26A5353q's UpdateBrainLibrary.dylib is still amd64+arm64 mach-o, has symbols, and has the whole decompression code statically linked (_compression_decode_buffer etc).

[blacktop]

what exactly are you asking for? you need to be more specific; I have a ipsw comp command that can decompress all the algos (if given a file) but these call into the same lib that your talking about which is why it only would work on a macOS 27 host