I'm currently on Macbook Air early 2015 (I think) and I'm dual booting Mac OSX Sierra and Windows 10, I got up to installing refit and when I restarted all that showed up was a blank grey screen with the refit logo and no options, I'm writting this on windows because I can hold option on boot and lets me open windows, so can you please help me.
EDIT: I can't boot into macosx