I think you should leave the original ecm for the moment, and consider the bcm. Your vehicle was manufactured in February 2010 and your bcm p/n is 284B2-JD12B. The donor you have is 284B2-JD12A, and was for those manufactured before yours going back to 2007. So I suspect the donor bcm might not work for your car because it's a previous version. On the other hand an updated version that would work for your vehicle is 284B2-BR01A for those produced till November 2011. I should add that the donor you have now is Siemens, while yours and the later version are Continental. Post the full numbers you have on the original bcm. I'd like to check the pin code.

The p/n for your ECM is 23710-BR40A (new: 23710-BR40B). The donor is an earlier version with 23710-JD78B. As I said, use your original ecm with a replacement bcm. At any rate do not use a part that's an earlier version  to yours.