I understand there are typically multiple versions of an ECU rom image for a particular model and year.
In my case, there are three rom images from Subaru for the 2004 STi.
What I'm a bit unclear on is what the preferred procedure is for reflashing with a newer rom version.
Assuming I don't have the newest version, should I:
A) Download my current stock ECU rom image and put it away for safekeeping and then upload the newer stock image version back to my ECU.
B) Download my current stock ECU rom image and put it away for safekeeping and then cut and paste the values from the tables in the newer rom image into the tables for my current rom image, and then reflash my "updated" old rom image?
Am I missing something that would point me one way or the other?