I was running beta5 (no issues) - upgraded to 8.0.0a and lost use of the stock remote. My box is Mini M8S II (S905X). USB mouse/keybaord work fine.
I just updated to 8.0.0b and still no stock remote.
I also own a Mini M8S II (S905X, 2G/8GB) and updated to 8.0.0b, and stock remote is working without problem. Of course, I always put the corresponding remote.conf in the root directory of my SD card. That's what I did for all of my TV boxes. Maybe you can try the same approach.