Well I was trying to help a friend by loading a tow tune in his 03 lb7. After getting the ECM Locked prompt multiple times when trying to download his stock file I was finally able to get it to download. Knowing the history of these bastard corrupt ecm's after being reflashed by the dealer i was kind of skeptical of moving foward with tuning his truck, but did so any way. So I went ahead and married the liscense to his vin and started uploading the tow tune. 5K Megabytes into the upload it locked up on me saying it was trying to reconnect to the ecm. After 3 hours of letting it try to reconnect I gave up. I tried to load the tune in again, and all I get is Bootloader rejected. Truck won't start/turn over. I figured the Pass Lock/VATS was causing this, so I tried to relearn that. No worky.

I have another 03 ecm, and was wondering if I use a Tech 2 can I load the proper tune in it by using his VIN? I know I'll have to marry the ecm to the bcm using the VATS relearn.