beav wrote:
2 I understand that there are tons of different rom revisions and everyone sticks with the original one from their ecu but what is the reason you cannot run other rom revisions assuming the hardware is identical or compatible? If the dealerships or factorys could update it why cant we? Something with immobilizer code that we are trying not to change?
First of all, welcome aboard!
That assumption is actually the key problem.
There is some cross-compatibility among ROMs and ECUs, however the cars have different sensor and actuators in different years. Mostly it's emissions control hardware, like the EGT sensors in the up pipe (my LGT had one, newer ones don't), or exhaust air pump (introduced when the up-pipe cat and EGT sensors were discontinued).
As far as I know, nobody has taken the time to build an authoritative list of what hardware changes happened during which years for which models in which markets. Without that sort of investigation, the only safe approach is to start with your own ROM, or factory ROMs that are known to be compatible with your ROM.
When the dealership does a recall to reflash, there's usually a few people who take note of their calibration ID before and after, so there is actually a fairly good understanding of those sorts of compatibility options. For example, that's what led me to switch from A2WC5210N to A2WC522N in my Legacy. The immobilizer didn't care.
