Micki
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« on: February 27, 2025, 03:35:13 AM »
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Hello,
We are talking about ENET communication in the BMW G82 during ECU programming. In TCP communication, the PC sends a compressed binary to the car. The binary is sent in packets of 4156 bytes, of which 4102 are payload (including a special header). The question is what type of compression is used? Compression options such as DEFLATE, LZMA, RLE, Huffman, BWT do not give such a result, as well as compressing binaries into 7z, RAR, ZIP archives with GZIP, BZIP2, XZ compression formats. The following data is based on observations. By changing one map in WinOLS, we listened to the communication every time. Single and double bytes are not encoded, but starting from 3 identical bytes in a row, compression occurs. In my opinion there is no repeatable pattern here, we have highlighted in red the confilcts compared to the pre-established previous logic.
The pictures show screenshots from WinOLS and corresponding data from WireShark.
I will be gratefull for any tips/informations according to continuing work this matter.
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