Help with unknown algorithm, possibly LZHUFXR and STALKER_LZA

Doubts, help and support about QuickBMS and other game research tools
qbmsuser
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Joined: Wed Jul 06, 2022 9:31 pm

Help with unknown algorithm, possibly LZHUFXR and STALKER_LZA

Post by qbmsuser »

I am trying to parse the firmware in various devices. To this end I sometimes need to decompress various code segments which are compressed with an unknown algorithm.

I currently have one example where a small code segment (eg 4KB) is decompressed correctly using the LZHUFXR and STALKER_LZA algorithms (found with QuickBMS comtype scanner 2). However, when large code segments are decompressed using the same algorithms, the actual result begins to diverge from the expected result at some point, eg 20KB.

Would someone be able to help me to refine (?) the parameters for these algorithms to achieve the correct result? Does the solution have something to do with dictionary size?

I have attached two samples, compressed and correctly decompressed (Comp and Decomp). The larger sample is the one that is giving me problems.