Yosemite Install Issue, gray stop sign - GA-H87N-WIFI

[LucasRussi]

Yesterday I tried to install Yosemite in my build. I'm currently running Mavericks.
Made the bootable usb with Unibeast, everything as the guide says.
When I boot from the usb it enters the apple load screen, loads for a few seconds, and then stops with a gray stop sign. This is before ever reaching the installer.
I read that this may have something to do with the new kext signing feature in Yosemite. Also with the exclusion of support for third party SSD's.
Tried with bootflags. But I'm really out of options.
Any help will be appreciated.

Here are the details of my build:

GA-H87N-Wifi motherboard
1 tb SATA HDD
Samsung EVO 128 gb SSD
Intel I3-4340
Crucial Ballistix 8gb RAM (4GBx2)
Pcie Tp-Link 450Mb DB W/N/3a TI-wdn4800

 

[synnys]

make sure you set boot options in you bios to legacy only.

then try with:

-x -v maxmem=4096

 

[LucasRussi]

make sure you set boot options in you bios to legacy only.

then try with:

-x -v maxmem=4096

I was already booting from the flash drive. The bios setting was ok.
In verbose this is what I get:

 

[ciwoc]

I had the same problem. And yes, the solution was going to bios setup and select "legacy only" option on the BIOS Features -> Windows 8 Features -> Boot Mode Selection.

Thank you synnys