Vida CEM swapping

matija0610 · Post by **matija0610** » 09 Oct 2022, 11:42

sorry, but I don't understand your question.
hope I helped 5ft24, who asked where and how checksum is calculated.

ele288 · Post by **ele288** » 09 Oct 2022, 14:59

thank you guys, I did the checksum and tomorrow will program my CEM. I was looking in to the config parameters and let say for instrument cluster you have few values like: 0x01 usa 0x02 uk 0x05 europe and 0x00 undefined. What I am looking is to have" user defined" settings in the cluster like service intervals etc, is that the 0x00 settings?

oscilloscope · Post by **oscilloscope** » 10 Oct 2022, 11:06

matija0610 wrote: 09 Oct 2022, 11:42 sorry, but I don't understand your question.
hope I helped 5ft24, who asked where and how checksum is calculated.

My question is how can a checksum be calculated for only part of the flash dump but not the entire flash dump ?

ZRimaZ · Post by **ZRimaZ** » 10 Oct 2022, 11:41

oscilloscope wrote: 10 Oct 2022, 11:06

My question is how can a checksum be calculated for only part of the flash dump but not the entire flash dump ?

In this case you have to read your hex editor's help about checksum claculation of selected area...

oscilloscope · Post by **oscilloscope** » 10 Oct 2022, 12:37

ZRimaZ wrote: 10 Oct 2022, 11:41
oscilloscope wrote: 10 Oct 2022, 11:06

My question is how can a checksum be calculated for only part of the flash dump but not the entire flash dump ?
In this case you have to read your hex editor's help about checksum claculation of selected area...

it won't help..

my understanding is these flash files would have some sort of internal checksum to ensure integrity, changing that would surely change the entire checksum calculation. changing some of it would save the checksum calculation in a area which has data already in it.

ZRimaZ · Post by **ZRimaZ** » 10 Oct 2022, 12:53

oscilloscope wrote: 10 Oct 2022, 12:37
it won't help..

my understanding is these flash files would have some sort of internal checksum to ensure integrity, changing that would surely change the entire checksum calculation. changing some of it would save the checksum calculation in a area which has data already in it.

Look: I'm doing this job every week 2-5, sometimes - even more times per week and would you like to make me sure that I do not know what I'm doing and that I'm lying to you?

One more time to those, who are not able to read and understang english text (sorry, my english is not the best one):
- at address 000EBD00 is length of config block
- at address 000EBD01 is checksum 8bit of the config block
- starting from address 000EBD02 to the address 000EBD00 + value from 000EBD00 is the config block itself.

Do you need more exact explanation? There will be no more

Sorry for angry style of my text, but it had to be clear for you already few pages before...

oscilloscope · Post by **oscilloscope** » 10 Oct 2022, 14:42

ZRimaZ wrote: 10 Oct 2022, 12:53
oscilloscope wrote: 10 Oct 2022, 12:37
it won't help..

my understanding is these flash files would have some sort of internal checksum to ensure integrity, changing that would surely change the entire checksum calculation. changing some of it would save the checksum calculation in a area which has data already in it.
Look: I'm doing this job every week 2-5, sometimes - even more times per week and would you like to make me sure that I do not know what I'm doing and that I'm lying to you?
One more time to those, who are not able to read and understang english text (sorry, my english is not the best one):
- at address 000EBD00 is length of config block
- at address 000EBD01 is checksum 8bit of the config block
- starting from address 000EBD02 to the address 000EBD00 + value from 000EBD00 is the config block itself.

Do you need more exact explanation? There will be no more

Sorry for angry style of my text, but it had to be clear for you already few pages before...

i never said you was lying to me ! dude calm down, have a drink of whiskey , or somthing. now the fact you do this sort of thing alot you should be very good at explaining the process, not get angry when somthing I have been taught is not correct and its conflicting!.

the picture that was provided earlier on , i looked and saw that all is in black , / high lighted , which i thought was you checksum from 00 through too 80 , and using 00 + 01 (DF) as the checksum location. which made little sense

ele288 · Post by **ele288** » 11 Oct 2022, 10:53

Just wanted to report that it works, did manage to turn off DRL and some other things, the only bit 0x04 that is responsible for service interval hasn't been change (vida shows as service interval for UK diesel market) but have no reference what other settings should be there to unlock "user defined settings" in instrument cluster. Thank you again for all the pointers,

5ft24 · Post by **5ft24** » 11 Oct 2022, 11:04

you can change service intervals and a LOT of those options in VIDA for free...

ZRimaZ · Post by **ZRimaZ** » 11 Oct 2022, 11:24

5ft24 wrote: 11 Oct 2022, 11:04 you can change service intervals and a LOT of those options in VIDA for free...

Nope! If "user defined settings" in config is not set, you can not change intervals in Vida. For older P2 cars it can be done, but for newer ones - no.