Unibeast/Yosemite USB freezes halfway through loading installer; shows "NO" symbol (pictured)

[Richie3000]

I have gotten past that by making sure the USB drive is plugged into an USB2 port instead of a USB3

Great info, that got me past the NO symbol...

Now i've gotten to the point of installing the first half of Yosemite on my drive but when it restarts for the first time, I get a "Can't find mach kernel" message and can't proceed any further.

I've seen another thread (http://www.tonymacx86.com/unibeast/...ind-system-library-kernels-mach_kernel-2.html) where there's apparently a couple lines that need to be removed from the (/Extra/org.chameleon.Boot.plist) but that didn't do the trick for me either.