Pretty sure the default is Blackvue-XXXXXX, but can't remember, so long ago from the default state.
I'm just wondering what the purpose of changing the SSID would be, and why it would be nessecary to include into a firmware update?
Unless there's multiple "Blackvue-YYYYYY" in the same area and subject to overlapping wifi-signals this shouldn't be any thing of concern. And Blackvue hasn't specified the reason for this change.
I'm wondering what kind of reason lies behind this...