i have an ostrich hooked to my 7730 running code59, i downloaded the emulated bin to tunerpro (i wanted to burn a chip) i made a couple changes to startup and uploaded to emulation, and the car runs like complete crap..

this was a new tunerpor install and i noticed under preferences "disable checksum by uploading 0xaa to offset 0x08

i think that's why its running like crap, i'll verify when i get home from work, although the maskid (progid) is set to aa in the bin

when i burn a chip do you need to do anything with the checksum?

You do not need to do any thing to the check sum and mask does not matter. The check sum is just that a check of bits.

Using 0xAA in place of the maskid is required when using the Ostrich. This disables the code from testing the checksum. It is required as you can change a byte here and a byte there via the real time emulation, which changes the checksum value.

It doesn't cause an issue as long as the key is on. Where it causes an issue is at the next key-on. The checksum won't match and the ECM goes into true limp mode.

When burning a chip it is best practice to use the proper maskid. This way the ECM will test the checksum at power up. And rapidly blink the SES/CEL if it doesn't match while also going into limp mode.

RBob.