My guess is you will be ok flashing the firmware from Andy's site but I would reach out to him to make sure. Let him know your issue...I bought it from Andy, but I think I flashed it with the official Dahua firmware some years ago. This explains why I'm seeing "Algorithm authorization failed, please import license." Since I'm using Blue Iris, I don't think I need these algorithms. I guess it has something to do with AI detection?
You are correct, it should be this model: IPC-T5442TM-AS. That's why I couldn't locate it on his website.