First time poster here, looking for some help.
I was tuning a 2003 Sierra 5.3 and the ECM bricked during the second flash of the day. Bad battery ground
.The ECM part # is 12576106, but I had a 12200411 laying around so I threw it in the truck. I was going to try to flash the stock 5.3 Sierra file onto the 411 but it said the vehicle said not licensed and didn't give me the option to license it. I put the 12576106 on my bench harness and it still seems like its bricked. Having a hard time finding another 12576106 for a reasonable price so I'm looking for other options.
Will the 411 work in place of the 106? And if so, why can't I license it?