I've got a 2019 Trail Boss w/ the sd reader slot in the console. I went ahead and purchased an Nav SD card from eBay, Genuine GM part number: 84528704. Came in a sealed GM bag and everything. Talked to my service manager at the dealer to schedule a time to flash the radio with the SD card installed, brought it in, and they are telling me they can't do it. I've got the highest trim radio you could get on the 19 trail boss as I got the Cov II package when I ordered it. Anyone know what gives here? I watched a youtube video that even though you have the SD card reader, you need to swap out the main module located behind the glovebox to make this work. I'm lost on this...thought this would be an easy upgrade.