flashed a bin from the 2002 files - 2002 Chevrolet Express Van Automatic L31 5.7L 4L60e 2wd (12212156) Lean Cruise.bin - accidentally did clone instead of os, parameters, and boot.

This file has the seed key set to FFFF which is obviously not valid. Also, the broadcast code seems to be invalid as well (in PcmBinBuild it shows up as question marks)

Any easy way to recover this without opening the ECU?
I am open to letting it sit on my desk and brute force for a week if need be.

I have tried setting the seed to FFFF in PcmHammer but it doesnt work (and it shouldnt because thats not valid).

It seems to me that the seed key is calculable in a predictable manner from the broadcast code, no? If the broadcast code is 0000 can that ever have a valid seed key? Or, will i be forced to open the ECU to fix it?