If select Windows at boot time (holding ALT/OPTION), it boots fine. If I select Windows via Boot Champ (OSX), Startup Disk (OSX), or Boot Camp Utility (Windows), on next reboot or powerup the fullscreen whitish/greyish screen never goes away and nothing boots up. I have Yosemite on an SSD in bay 1 and Windows 8.1 EFI on a separate SSD in bay 2. Computer is a 2010 Mac Pro. I switch OSes a lot and it's a hassle to sit and wait, and time the keyboard press, wait longer for the OS options to appear, etc. Obviously I would love it if I could get the usual boot switching methods to boot Windows. I've tried clearing NVRAM multiple times. Anyone have any thoughts or helpful tips?