pcmhacking.net

Yeah, I was thinking I could disable a section of code and use a chunk of address space that was used for that code.

IIRC there are unused tables depending on configuration, sounds like a plan ...

Looks like there is $264 (614) bytes in the engine calibration segment in 12212156 which I guess would be the OS you'd be likely to target. Theres plenty more space around, it just depends how tidy you want to make it and how hard you want to work on it. Maybe you could just read out of another segment. So long as everything is checksummed right, tunerpro isnt going to care which segment the setting is in, and just update the sum for the right area, and the OS is on bare metal hardware and can read anywhere too.

yep that's what i did in enhanced mod, disabled EGR code and got a huge section of code and parameter space to use, find something not needed that can be disabled somewhere then use it's space!

Nice Work!

bubba2533 wrote:I think the biggest part I haven't figured out is where I want to store the new tables. I plan on doing this starting with the 12587603 OS.

The target OS is 12587603.

The1 wrote:yep that's what i did in enhanced mod, disabled EGR code and got a huge section of code and parameter space to use, find something not needed that can be disabled somewhere then use it's space!

Nice Work!

That's exactly the code I was looking at replacing.

This is what I've found so far. Still more digging to do. Edit: Yes this is all for 12587603

I know when I do a cal flash with EFI Live, that it states that it is flashing 96 kB of data. When I was playing with doing the launch control patch, I was looking for unused portions of the "cal" data. One thing that I noticed is that there seems to be a "hole" at the end of the speedometer segment and where the actual OS starts. I am playing with a 512 kB OS, but I think this holds true for the 1MB PCM's as well. The last calibration segment is the speedometer. In the 12202088 OS, it is from $0001EEA0 to $0001EF9F. The actual OS doesn't start until $00020000. Interestingly enough, this empty segment doesn't have any data or code in it. I had originally thought to use this blank area, but then realized that it might not get flashed by say PCM Hammer or LS Droid. Funny enough, I did a calibration flash using EFI Live and it did write this segment of data. But I don't think that it is part of any check sum calculation either.

I think overall, it would be easier to try and use the existing EGR section. But this portion of the OS might become useful for other things.

I'm working on disabling all the EGR code and references to the EGR RAM section. There aren't that many outside the EGR code so it shouldn't be that hard.

For the 12587603 OS at the end of the Speed Cal there is 0xED (237) bytes (0x0001FEF2 to 0x0001FFDF)

If I need more space that could be used.

Ok, I think I'm done with disabling all the external calls to the EGR code space

I put it into a xdf and attached.

Also for anyone that is interested I calculated the bytes wrong so here are the correct numbers.
That was really the easy part...wish I knew how to use a higher level language to write the new code

Edit: Fixed Ram Location Description

Ok, I think I've figured out how the updated VE table will look.

I'm going to keep the stock VE table, but double the MAP range. So it'll start at 15 kpa and go to 195 kpa. On top of that I'm going to make a new VE table to go from 195 kpa to 375 kpa.

That saves a few hundred bytes of CAL space compared to how I was going to do it before. And it gives really good resolution. Only annoying part is that it breaks up the VE table into two sections.