Well, rather than try to mess with another clueless dealer, I went the hacker way.
Found information about disassembling the radio itself (the silver box), to get the EEPROM chip on the circuit board, and using a $10 USB eeprom programmer off ebay, was able to change the vin myself.
Got the EEPROM updated, radio reassembled, and reinstalled in the equinox, and it's working perfectly.
If anyone else ever has to deal with this, hit me up. Time to pull radio, disassemble, flash the eeprom, reassemble and reinstall in vehicle was about 3 hours.... That's actually less time than I wasted at the dealership only to have them not be able to do it.
Last edited by DenverGp; 08-30-2019 at 08:13 PM.