LLY no start after attempting to read ecm

[blazin dmax]

Tried to read the tune out of a friend's 04.5 LLY. It got stuck and then popped up a message "bootloader rejected. Reason: controller has returned to normal operation. Please retry the operation." So I waited for the 15 second countdown and everything. Unplugged the cable from the obd2 port. Cycled the key and made sure the truck still started and it did. Turned truck off and tried again. This time it got stuck and gives me a "bootloader rejected. Reason: no response from ecm." Waited the 15 seconds and now the truck is in a no crank/no start condition. I checked all the fuses and didn't find anything blown. Unhooked battery cables for 10 minutes and that didn't help.... I'm at a loss now. Any help is greatly appreciated. Trying to get this thing on the road today. My number is 928-925-3553 if anyone has a quick fix for me. I will check back here every 15 minutes or so. Thanks ahead of time.

[blazin dmax]

Went ahead and replaced any ecm/ignition related fuses. Still no help. Now when I turn the key to the on position. The gauges and everything come up like normal. Then they turn off like you turned the key back off. Then they power back up again. They will do this a few times and then stop like they are in the off position... Anyone ran into anything like this? I'm assuming the ecm is bricked?

[GMPX]

Ok, it is pretty much impossible to 'brick' an LLY ECM just by reading it. The read process cannot modify anything in the ECM that would cause any data in it to get erased or modified.
My only suggestion was going to be unhooking the battery for a few minutes to reset everything but you've already done that. Maybe check DTC's then clear all DTC's, I'm really not sure what else you can try.
I would not be flashing this truck, it sounds like there is something hooked on to the data bus that is causing all sorts of issues for you.

It is Sunday morning in my part of the world so I probably won't be back on-line for a while, but I don't have much more to suggest to be honest.

[blazin dmax]

Thanks for the response. After talking to the owner, it sounds like this truck has something else wrong with it. It was previously tuned with a bully dog tuner. He tried to return it to stock a few weeks ago and the download failed 3 times so he just gave up. But the truck still ran fine... Wish he would of told me that before all of this. Guess I'm going to look for a replacement ecm.