Hi @brandonchang,
I know you mentioned this driver is for Yosemite, however I am still on Mavericks and not in a position to upgrade.
I followed the steps you mentioned but it didn't work for me. I followed the steps you mentioned and didn't see any error message with kExt utility. Is there any way to debug this or anything else I can do to make the keyboard work ?
Symptoms I am seeing: Backspace/spacebar and some of the other keys aren't working.