One other thing that is odd is that each time I quit MacMiner it then fails to restart until I delete ~/Library/Application\ Support/MacMiner, which is a bit unsettling.
Managed to get the unload to pass without errors now (by loading / unloading a few times), but I still get the warning when starting BFGMiner, and if I proceed despite the warning I get the error with the 'failed to initialise (incorrect device?)' m…