I'd suggest trying the Arctic Fox/NFE toolbox firmware/update tool. Not sure if it will allow you to recover, but at this point it is worth a shot.
use the NFEtoolbox and attempt an update, if it hangs or does not update properly you can try contacting Maelstrom on the github message board, I believe there are some command line functions available for the updater.
You can use the updater to attempt a write with the arcticfox firmware, if it works, and you don't like the added functionality you can always go back to the wismec firmware.
NFE Team