Sorry, I’ve searched high and low but can’t find them. Someone had detailed how they edited a file in the system somewhere to re-enable the disabled SIM-2 slot, but I can’t find the post now. As I said, it wasn’t relevant to me so I didn’t bother to save it!
That said, the commercial versions of SFOS 5 will hopefully be out by the end of the year, so hopefully full support for the 72 variants will land with that.