Sorry, but like Grizzy i can't see the problem. Run a valid command with '2' as the write path. If it can't write to the card as '2' then it will simply fail and there will be no repercussions from that. Then you know that the correct path to the card is '1' and that the device doesn't have RWFS partition so you can then run again for '1'. No problem at all really.

To be clear: Devices with RWFS write from the main device to that partition as '1' and the card as '2'. Those without write only to the card from the device and the path is '1' and '2' is not valid with them at all.