P59 ECU swap but incompatable OS.???

Can anyone steer me in the right direction? I have an 03 Suburban with a P59 OS 12579405. I some how bricked it trying to change the OS to Real Time Tuning. I have a spare P59 from an 06 Silverado with OS 12587811. I licensed the spare, did a read, turned off VATS and then opened a compare file of my current tune and made all the appropriate changes. I wrote "entire" and the truck started but idled higher then my desired idle. When I did the compare, there were a bunch idle, airflow, and throttle parameters that were different. I adjusted some stuff and got the idle fixed but the truck is like in limp mode or something. If I stab the throttle it opens once or twice quickly but then there is no more throttle response?? The throttle wont open fast, nor will it open higher then 20.4% at full pedal, in gear outa gear, doesn't matter. Ive searched all over and I can not find anything straightforward enough to make the proper changes to the parameters with the throttle. Do I have to download the OS from the old ecu?? If so can something tell me how or where to find the directions on how to do it? Unfortunately this is my only vehicle so im stuck without a truck until I can figure this out. Thank you in advance for any assistance.

03-05 ETC hardware/calibrations are not compatible with 06-07 Classic ETC hardware/calibrations. If you saved a copy of the 03 Suburban stock calibration just write entire to the 06 Silverado PCM. You will have to do the 30 minute VATS relearn if you want to retain the VATS.

Thank you so much for your quick reply. I figured I had to do something like that. So im basically taking the as found from my 03 and write entire to the 06 pcm? I just dont want to brick another one doing the wrong thing.

Correct. You might want to use a bench harness if you bricked the original programming it in the vehicle. Do you have an aftermarket radio or remote start or alarm installed in the Suburban?

Thank you for your help. I wrote my 03 "as found" as write entire and then uploaded my last tune using write calibration. Trucks back up and running. Thank you. I definitely need a bench harness. My radio got once already so now I just some fuses and this time I'm pretty sure it was a low battery issue. Too risky in the truck. Thanks again.