It shouldn't matter.
I don't really know what else to tell you that I haven't already said. If you're actually putting the file in the correct folder and you're reasonably sure your file is valid (https://github.com/retrogamehandheld/OpenDingux/blob/master/Readme.md) then there shouldn't be a problem.
Update: I was finally able to get descent to work, but only after updating to the rogue 350 1.7 firmware and using the OPK hacky launcher. It won't work just using the explorer and using the same file that works with the OPK hacky launcher.
As far as gameplay, looks great, but I can't get the right analog to work. Can't really play descent without additional flight control. Hopefully this will be fixed soon.