delco ecu identify and VATS off

[solitaire]

Thanks,
How about CRC? Someone known algo and block size?

[antus]

Hiya Folks,
I can't remember if I need to byte flop the entire .bin file or just segments and I haven't stumbled across all my notes from back in the day.

You can use the gq4x4 eeprom programmer software (GQUSBProg) which is a free download to load the bin, byte swap all of it (A<->B icon) and save it again. It is byte swap the whole file. https://www.mcumall.com/downloads/

[In-Tech]

Hiya antus, I actually have one of those eprom programmers and it is the software that I used to byte swap simply, it did the entire .bin file. I just can't remember if the entire file was needed or just a segment or two? I think I have a black box at the shop so I can experiment better when I get time and hopefully find it. solitaire, I wish you were closer, I could do for you quickly on the bench via the OBD2port

gmc yukon_ab28f400bx_99_ori_byteswap.bin

[antus]

yep for the background the byte swap is because of how the chip is working connected to the ecu (16bit mode, with the opposite byte order), thats why it applies to the whole chip. there is nothing like that at the segment level.

[In-Tech]

Thanks antus, I'll see what I can find. When I find the segment with the VATS bit, shouldn't we be able to set the bit then find an unused FF and set it to FE so checksum matches, then byteflop again so he can program the flash chip? Sorry if these are dumb questions.

[antus]

Yes, thats right. From comparing the output of other software I can see vats disabled is 00 to 01 at F0BE and Checksum is subtract 1 44 to 43 at EF94. I would assume sum is checksum-16 at EF93 but I havnt verified the endianness to be sure of that. Its the system segment, and sum is in the system segment header.

[In-Tech]

Awesome antus
Do you feel confident that he should write this and re-solder?

[antus]

yes I do, and hopefully we can come up wiith a software flash tool, and someone can make XDFs later. Just remember to byteswap it back before writeing.

[Gampy]

There is also C# source code for a tiny command line ByteSwap program included in the DevTools folder of the PCM Hammer repository ...

Hope this is ok to post?

It's use is simple, ByteSwap <input file> <output file>

ByteSwap.exe

[In-Tech]

To solitaire,
"Just remember to byteswap it back before writeing" by antus