repeating what i said in email for the benefit of others.
the immobiliser is a seperate system to the ecu, they don't communicate as is common with other cars, its a seperate unit behind the drivers seat in the cockpit, you have to remove the cover to get to it.
if its a used ecu and its not booting then there may be an issue with the ecu being damaged, unfortunately i have to open the case to get a new flash into it and check it out, opening the case loses any warranty on the ecu itself, and they're very difficult to repair.
Sometimes people send me used ecus without testing them, i get it, flash it and send it back and it doesn't work, since i reflash them on the bench i can't tell if its 100% functioning, only if its 100% dead, i have a couple that work fine on the bench but don't in the car, since its usually an input or output that the car uses that i don't need to reflash them, then of course the person who sent me the ecu says it should have been working, and i'm left swapping out one of my working ecus with their busted one with no real way of proving that it was DOA, which is why i have a bunch of dead ecu's.
I can reflash it, but if its not working and its a hardware issue, it still won't work when you get it back.
Make sure the pins aren't bent either.