I’m having the same problem with the start up volume blasting. I carried to dealer 4 times already. First two times I got the standard answer( we never heard of that problem). Last time I was told by dealership that Gmail was aware of problem and working on a fix. Today I was told even if they replaced radio it would do the same thing. I was told to contact gm and maybe they would do something. As of now I have been on hold for 2 hours. Yes you read that right 2 hours. Probably my last gm product. No customer service at dealership or gm