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Title: M5.41 speed governor, CRCs Post by: SundayNightDriver on January 29, 2011, 08:10:50 AM Here are some files from a pre-1999 Audi S8 (4.2 32V, 340 bhp). The ECU uses an Intel MCS-96 microcontroller and 2x64 KB ROM through bank switching.
The first file is stock. The second has the 250 km/h speed limiter removed, and the third has tuned maps and the usual speed limit. http://leitseite.net/misc/ecu/s8_stock.bin (http://leitseite.net/misc/ecu/s8_stock.bin) http://leitseite.net/misc/ecu/s8_no_speed_limit.bin (http://leitseite.net/misc/ecu/s8_no_speed_limit.bin) http://leitseite.net/misc/ecu/s8_tuned.bin (http://leitseite.net/misc/ecu/s8_tuned.bin) I compared these files, and found the following changes from the first to the second file. 0x8442 - 6 bytes changed to FF. Doesn't seem to be instructions (and 0xFF is RST on this CPU, not NOP) 0x87C4 - 67 00 changed to 00 FF 0xB239 - map with slightly raised values 0xB57A - same as above 0xBF00 and 0xBF03 - probably the checksums for ROM bank 0 I wonder if this ECU really has a VMAX setting or if the limit was implemented through some other method. Is this possible? Does anyone know more? |