ASUS Rampage III Extreme, PCIe SSD Boot

[lsiravi]

Hi Modders

I have an R3E/i7 960/BIOS v1502 (official)/Crucial SATA SSD/Windows 10. I recently acquired an Intel 750 PCIe SSD, that I'd like to use in the machine as my primary (preferably only) drive (the SATA SSD appears to be on the way out)

The Intel 750 is in a Gen2/X16 slot (the second red one from top), and the drive is detectable/usable by Windows. However, in the BIOS (I'm still on 1502) it is not selectable as a boot drive on which to install OS.

• Is there a modded version of the R3E BIOS that will resolve this particular problem? 
  
• If yes, which version would best suit my need? (Link, please?)
  
• With that version, what options should I change from defaults in order to boot from the Intel 750?
  

Much thanks in advance
LSIRavi