Have done the trans firmware update:
1) It takes a long time (about an hour from memory), therefore,
2) Make sure you have a high-current charger attached for the duration unless you want to be introduced to the transmission fail safe mode. I use a 21AMP charger without issue.

Is there a particular problem you are trying to solve with the transmission?

If you would prefer for an independent to do the work, I can recommend Northern BM.

What do you want coded?