GM L8T E93 ECM Swap Programming Problem

Hi everyone, I have swapped a GM L8T with E93 ECM and 6L90 into a Hummer H1.

Engine and ECM are used. Transmission is rebuilt with new TCM.

The ecm had been sent out to HP Tuners to be unlocked and received.

All wiring is done. Verified using GM GDS the ecm communicates and I can read and see data. From there I proceeded with programming the tcm with success using AC Delco TDS/GM sps. From there verified data can be viewed using scan tool.

I used hp tuners to begin programming and changing tune files.

I tried to turn off VATS, failed. Tried to do something simple like delete a dtc, failed.

I get a message that says. X7F Negative Response Code.

HP tuners said it's battery being low, I have a charger on the battery. They said wiring issue, I have communication.

So I sent the ecm and mpvi3 as they asked. Waiting for an update.

Am I doing something wrong or am I missing something?