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Author Topic: Can someone teach me how to manually calculate eeprom checksum?  (Read 14674 times)
1gcrazy
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« on: January 30, 2023, 11:28:57 AM »

So as some of you might know, the ME7eeprom tool doesn't cover the me7.1.1 eeprom's which are generally 95160 or 5P08C3. Can someone help me understand how to change a vin in the eeprom in these ecu's? I've been stumbling through it for years and usually I'll revert to cloning if I absolutely have to but I'd like to learn the logic. I'm not very good with hex.
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BlackT
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« Reply #1 on: January 30, 2023, 12:59:42 PM »

Read it like ME7.5 eeprom, change VIN, calclute ckc via EEPROM programer and write like Me7.5
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1gcrazy
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« Reply #2 on: January 30, 2023, 01:25:05 PM »

Read it like ME7.5 eeprom, change VIN, calclute ckc via EEPROM programer and write like Me7.5

How do you calculate with eeprom programmer? Which programmer? I haven't found anything that works with it reliably. Ksuite doesn't read out the eeprom on certain ecu's. It's all FF's.
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BlackT
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« Reply #3 on: January 30, 2023, 06:42:18 PM »

http://nefariousmotorsports.com/forum/index.php?topic=1168.0title=

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1gcrazy
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« Reply #4 on: January 31, 2023, 03:02:38 PM »

As far as i'm aware this tool will not calculate eeprom. The tool that will is Checksum95040.exe but that wont do larger files than 95040. 95160 and 5P08C3 don't work. I wish they did. That's the tool I use to calculate the 95040's. Matter fact, some 95160's have 00's or FF's at the second half of the prom and i've been able to cut that section off, calculate and add that section back on but I don't know enough about the correction to be able to use it any further than that on the bigger files.
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BlackT
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« Reply #5 on: February 01, 2023, 07:08:24 AM »

So again
Read it with this tool as 95040

Do immo off and calculate checksum with Checksum95040.exe

Write that file as 95040
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1gcrazy
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« Reply #6 on: February 27, 2023, 02:22:34 PM »

But a 95160 and 5p08c3 file are bigger than a 95040. It writes FF's to the rest of the file from what I remember. I don't see how that would work.
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BlackT
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« Reply #7 on: February 27, 2023, 03:38:43 PM »

It does not touch rest of file, only half file is writen
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1gcrazy
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« Reply #8 on: March 07, 2023, 11:21:38 AM »

It does not touch rest of file, only half file is writen
And the checksum doesn't need corrected in the rest of the file?
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1gcrazy
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« Reply #9 on: March 07, 2023, 11:45:34 AM »

According to HXD the checksum is different after only checksumming the 0-1F0. Which is why I don't trust only checksumming the first half.
The way I did it is, read the 95160. Pulled 0-1F0 out, created it's own file. Saved that new file, checksummed that with 95040Checksum.exe. Then reinserted the top half into the 95160 file and saved. Checked the checksum via HxD and compared to the original 95160 checksum and it's different.
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BlackT
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« Reply #10 on: March 07, 2023, 01:32:54 PM »

Why don't you try write it to ECU?
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