Checksum???

by **Simanic** » Tue Feb 19, 2013 11:31 pm

Hello guys!

Can anybody help me and say correctly what mean checksum, or give some link where i can read it?? Tnx in advance!

by **kennfeld** » Tue Feb 19, 2013 11:48 pm

you ask to know how to correct the checksum but you didn't tell for what car where is your brain ? :)
:mrgreen:

by **Ionut** » Wed Feb 20, 2013 12:23 am

Checksum (of a file) is a string that is generated from content of a file. If any byte from that file changes, the checksum will change.
Read more about CRC and Checksum on wikipedia: http://en.wikipedia.org/wiki/Cyclic_redundancy_check & http://en.wikipedia.org/wiki/Checksum

On ECU, checksum is used to tell ECU that file inside his flash was not altered. That`s the reason why an ECU does not accept files with invalid checksum.

by **VitalyR** » Tue Feb 26, 2013 7:09 pm

Tha main information about checksum: if it is not right it will be 2 variants
1. Engine do not starts
2. Internal ECU fault, but starting engine
So, if something is changed-calculate the CS. Winols do it automatically.

by **mmaigret** » Tue Mar 05, 2013 3:48 am

My understanding is that, depending on ECU, there may be multiple checksums. Also, I believe one must have additional modules (OLSxxx) in order for WinOLS to calculate the appropriate checksums. Please confirm as I am still learning...

by **Tunez1** » Fri Mar 08, 2013 2:05 pm

Hi,
Does ols demo version cover this auto checksum correct?
Is this change visible at an address, to see original and modified?

I am yet to purchase full version :think:

by **bibinox** » Fri Mar 08, 2013 10:31 pm

It is called checksum for historical reasons ,mainly because 1st types of tamper security was plain sum of bytes. Thisdays would be more appropriate to call it hashes :)
It all depends on manufacturer (of ecu) which algorithms will they use and on which areas.

by **sgjpro** » Mon Mar 11, 2013 8:59 pm

hello all,

by any chance.. can any one please help me checksum correction for the suzuki swift mjd merelli ecu (OLS294)?
regards,
Sj

by **mexanico1971** » Wed Mar 13, 2013 5:28 am

sgjpro wrote:hello all,

by any chance.. can any one please help me checksum correction for the suzuki swift mjd merelli ecu (OLS294)?
regards,
Sj

post ori and mod !
so some one can help you !

by **julianstefanov** » Sun Mar 24, 2013 9:42 pm

A small question. When you change the maps of any ORI, you going to change the Checksum of the file 100%. How exactly WinOLS or any other software can keep the same checksum calculations for already modified file?